Instantanous propagation of the 'electrostatic force'?
z@z
These quotes show that HEINRICH HERTZ has indeed found in his
experiments that ELECTROSTATIC effects propagate INSTANTANOUSLY
and NOT at c as generally assumed.
Interference effects between waves in a wire orginating from the
center of a brass disc and the electrostatic effects of the disc
can be measured. If oscillations of 35.7 Megahertz are used and
the speed of the wire waves is 200 000 km/s, we get a wave length
of 5.6 meters. If electrostatic effects propagate instantanously,
after 5.6 m, 11.2 m, 16.8 m, ... the wire must be in phase with
the electrostatic effect of the disc.
| > Heinrich Hertz, Gesammelte Werke, Band 2, Leibzig, 1894:
| I'll reproduce the translation by D. E. Jones from
|
| "Electric Waves being Researches on the Propagation of Electric Action
| with Finite Velocity through Space", Dover, 1962:
| Introduction, p. 8:
|
| "Nor was there any greater difficulty in producing interference between
| the action which had travelled along the wire and that which had
| travelled through the air, and thus in comparing their phases.
| Now if both actions were propagated, as I expected, with one and the
| same finite velocity, they must at all distances interfere with the same
| phase. ... But when I had carefully set up the apparatus and carried out
| the experiment, I found that the phase of the interference was obviously
| different at different distances, and that the alternation was such as
| would correspond to an infinite rate of propagation in air.
| Disheartened, I gave up experimenting."
| On the finite velocity of propagation of electromagnetic actions
| p. 110:
|
| "The total force may be split up into the electrostatic part
| and the electromagnetic part; there is no doubt that at shorter
| distances the former, at greater distances the latter,
| preponderates and settles the direction of the total force."
| p. 118:
|
| "In the second place, we notice that the retardation of phase
| proceeds more rapidly in the neighborhood of the origin than
| at a distance from it. All the rows agree in showing this.
| An alteration of the speed of propagation is not probable.
| We can with much better reason attribute this phenomenon to the fact
| that we are making use of the total force [...] which can be split up
| into the electrostatic force and the electromagnetic.
| Now, according to theory, it is probable that the former,
| which preponderates in the neighborhood of the primary oscillation,
| is propagated more rapidly than the latter, which is almost the only
| factor of importance at a distance."
| p. 120:
|
| "The interference does not change sign every 2.8 m. Therefore the
| electromagnetic interactions are not propagated with infinite velocity."
| p. 121:
|
| "Since the interferences undoubtedly change sign after 2.8 m in the
| neighborhood of the primary oscillation, we might conclude that the
| electrostatic force which here predominates is propagated with
| infinite velocity."
| I have a few questions on those procedures and results:
|
| Based on which requirements/measurements did Hertz decide whether or not
| "the apparatus was set up carefully"?, and
Apart from the constancy of the primary oscillation and the
possibility to compare at different distances the phase of the
wire wave with the phase of the action propagating through
the air, there is nothing which must be set up carefully.
| How did he determine pairwise distance relations such as "2.8 m" or
| "neighborhood" (if not by employing Einstein's procedures, based on
| the exchange of light signals)?
A simple tape measure is enough to determine at which distances
from the emitter the interference changes sign.
In any case, it would make sense to repeat this crucial experiment.
Wolfgang Gottfried G.
Previous relevant posts:
http://www.deja.com/=dnc/getdoc.xp?AN=530719931
http://www.deja.com/=dnc/getdoc.xp?AN=531225851
http://www.deja.com/=dnc/getdoc.xp?AN=531506436
http://www.deja.com/=dnc/getdoc.xp?AN=531614175
Frank Wappler
> In any case, it would make sense to repeat this crucial experiment.
Sure, experimental results may be obtained in any number of trials.
If the experimental procedure being conducted is _reproducible_
then it is even meaningful to _compare_ and relate the individual
results of the various trials to each other, quite irrespective of
whether or not they happen to be "surprising" or to "make sense".
Of course, in order to determine which (if any) aspects of Hertz'
experiments are unambiguously reproducible, one must reach
clarification and agreement on ...
> [Frank Wappler wrote:]
> > a few questions on those procedures and results:
> > Based on which requirements/measurements did Hertz decide whether or not
> > "the apparatus was set up carefully"?
> Apart from the constancy of the primary oscillation
How did Hertz/how would you determine whether or not
the primary oscillation is "constant"; and wrt. what else?
> and the possibility to compare at different distances the phase
> of the wire wave with the phase of the action propagating through
> the air, there is nothing which must be set up carefully.
How did Hertz/how would you determine which "actions" are associated
with "the wire" and/or "the air"; whether exclusively so, or at all?
> > How did he determine pairwise distance relations such as "2.8 m" or
> > "neighborhood" (if not by employing Einstein's procedures, based on
> > the exchange of light signals)?]
> A simple tape measure is enough [...]
How did Hertz/how would you determine the calibration relation
between various distinct "simple tape measures", or
between the same "simple tape measure" being used in various distinct trials
(if not by employing Einstein's procedures, based on
the exchange of light signals)?
Regards, Frank W ~@) R
p.s.
> Frank Wappler, thank you very much for the translated quotes.
You're welcome.
> > [(Btw., the copy of Band 1 that I found in the library
> > was published by J. A. Barth in _Leipzig_ ...)]
Would you kindly double-check where the copy of
"Heinrich Hertz, Gesammelte Werke, Band 2" was published,
to which _you_'ve been referring?
Tom Roberts
> These quotes show that HEINRICH HERTZ has indeed found in his
> experiments that ELECTROSTATIC effects propagate INSTANTANOUSLY
> and NOT at c as generally assumed.
Please read what you wrote. In a _static_ situation, _nothing_
propagates, because everything is static and nothing changes.
Note, please, that it is well known that the Maxwell's equations
plus the Lorentz force law predict no aberration for the
electromagnetic force due to a charge which is in inertial motion
wrt the observer (see, e.g. Feynman volume 2).
It appears that you make the same mistake for E&M as does Van
Flandern for gravity -- absence of aberration is _not_ a measurement
of any "propagation speed".
The situation is different for E&M and gravitation -- for
E&M this holds only for inertial motion, but holds exactly;
for gravitation it holds only approximately (except for a
universe containing only a single mass), but it holds for
any motion whatsoever (assuming a small and isolated mass,
and the observer is of negligible mass). For both theories
this is a really statement about the symmetry group of the
theory and the boundary conditions applied (no radiation
zooming in from infinity).
[I could not decipher the physical situation of Hertz's
experiment(s) from your remarks, so I respond _only_ to
the words quoted above.]
Statd differently: It does not look to me like Hertz's experiments
refute classical electrodynamics, in which E&M effects _do_ propagate
at c (not instantaneously). But I have not performed an analysis, I
merely note that nobody else claims they refute classical E&M.
Tom Roberts tjro...@lucent.com
z@z
| Wolfgang G. wrote:
| > Frank Wappler wrote:
| How did Hertz/how would you determine whether or not
| the primary oscillation is "constant"; and wrt. what else?
| How did Hertz/how would you determine which "actions" are associated
| with "the wire" and/or "the air"; whether exclusively so, or at all?
| How did Hertz/how would you determine the calibration relation
| between various distinct "simple tape measures", or between
| the same "simple tape measure" being used in various distinct
| trials (if not by employing Einstein's procedures, based on
| the exchange of light signals)?
Hertz was an excellent experimenter and I do not doubt that
it was rather easy for him to produce a constant oscillation
resulting in wire waves with a wavelength of 5.6 m. I'm neither
knowledgeable about nor especially interested in experimental
physics and it was some years ago when I studied some of Hertz'
texts. Now I deal only with passages I marked then. But Hertz
has well decribed his experimental techniques and I'm sure that
for an experimental physicist it should not be very difficult
to compare the phases of the oscillation propagating in a wire
with the actions propagating through the air.
Once again Heinrich Hertz about his first attempt:
"But when I had carefully set up the apparatus and carried out
the experiment, I found that the phase of the interference
was obviously different at different distances, and that the
alternation was such as would correspond to an infinite rate
of propagation in air. Disheartened, I gave up experimenting."
Nevertheless, also after having learned to (produce and) detect
an 'electrodynamic force' propagating at c, the actions at a
distance from the 'electrostatic force' did not disappear:
"Since the interferences undoubtedly change sign after 2.8 m in the
neighborhood of the primary oscillation, we might conclude that the
electrostatic force which here predominates is propagated with
infinite velocity."
| > > [(Btw., the copy of Band 1 that I found in the library
| > > was published by J. A. Barth in _Leipzig_ ...)]
|
| Would you kindly double-check where the copy of
| "Heinrich Hertz, Gesammelte Werke, Band 2" was published,
| to which _you_'ve been referring?
My copy:
Band 2, Leibzig, 1894, Johann Ambrosius Barth, (Arthur Meiner)
Unchanged reprint of the edition of 1895, #3112
Sändig Reprint Verlag, 1988, Vaduz / Liechtenstein
Interestingly I live in Vaduz, a capital with a population of
around six thousand residents.
Cheers, Wolfgang
Frank Wappler
> Frank Wappler wrote:
> | How did Hertz/how would you determine whether or not
> | the primary oscillation is "constant"; and wrt. what else?
> | How did he determine pairwise distance relations such as "2.8 m" or
> | "neighborhood" (if not by employing Einstein's procedures, based on
> | the exchange of light signals)?
> Hertz was an excellent experimenter and I do not doubt that
> it was rather easy for him to produce a constant oscillation
> resulting in wire waves with a wavelength of 5.6 m.
Easy or not, I'd like to be sure how he or you determined
(i.e. what he or you meant by)
"constant oscillation" and "meter" _at all_, trial by trial.
IMHO, a prerequisit for being an excellent experimenter
is to select experimental procedures and to define notions
that can be unambiguously communicated and reproduced.
> I'm neither knowledgeable about nor especially interested
> in experimental physics [...]
> I'm sure that for an experimental physicist it should not be
> very difficult to compare [...]
As an experimental physicist I can assure you that it is meaningless
to compare results of distinct experimental trials if they were
not obtained by the same measurement procedure.
This of course requires that the selected experimental and
measurement procedures be reproducible in the first place;
hence the conventional choice of the Einstein procedures.
Skól, Frank W ~@) R
p.s.
> | Would you kindly double-check where the copy of
> | "Heinrich Hertz, Gesammelte Werke, Band 2" was published,
> | to which _you_'ve been referring?
> My copy:
> Band 2, Leibzig, 1894, Johann Ambrosius Barth, (Arthur Meiner)
> Unchanged reprint of the edition of 1895, #3112
> Sändig Reprint Verlag, 1988, Vaduz / Liechtenstein
> Interestingly I live in Vaduz, a capital with a population of
> around six thousand residents.
Well - I rather refer to the copy available through the Library of Congress
Author: Hertz, Heinrich, 1857-1894.
Title: Gesammelte Werke, von Heinrich Hertz.
Published: Leipzig, J. A. Barth, 1894-95 [v. 1, '95]
Description: 3 v. front. (port.) diagrs. (1 fold.) 22 cm.
LC Call No.: QC3.H49
Dewey No.: 530.81
Notes: Each volume has also special t.-p.
Includes index.
Bd. I. Schriften vermischten Inhalts,
herausgegeben von Ph. Lenard.--Bd. II. Untersuchungen über
die Ausbreitung der elektrischen Kraft. 2. Aufl.--Bd. III.
Die Prinzipien der Mechanik.
Subjects: Physics.
Other authors: Lenard, Philipp Eduard Anton, 1862-1947, ed.
Control No.: 7361082
(Btw., the volume two in question seems to have been a second edition of
Author: Hertz, Heinrich, 1857-1894.
Title: Untersuchungen ueber die Ausbreitung der
elektrischen Kraft.
Published: Leipzig, J. A. Barth, 1892.
LC Call No.: QC661.H59)
Equally interesting is that only few (if any) of the about six thousand
cases annually in which "Liechtenstein" is misspelled in various ways
are being considered international incidents.
z@z
| Wolfgang G. wrote:
| > Hertz was an excellent experimenter and I do not doubt that
| > it was rather easy for him to produce a constant oscillation
| > resulting in wire waves with a wavelength of 5.6 m.
|
| Easy or not, I'd like to be sure how he or you determined
| (i.e. what he or you meant by)
| "constant oscillation" and "meter" _at all_, trial by trial.
| As an experimental physicist I can assure you that it is meaningless
| to compare results of distinct experimental trials if they were
| not obtained by the same measurement procedure.
|
| This of course requires that the selected experimental and
| measurement procedures be reproducible in the first place;
| hence the conventional choice of the Einstein procedures.
I agree with you in principle, but in the case we are
discussing, there is absolutely no need to include SR
reasonings. The experiments of Hertz precede SR by several
years and in addition to that they are not sensitive to
time dilation, length contraction and so on, because they
are performed in a frame at rest wrt the earth's surface.
So even if SR is assumed, clocks, rulers and simultaneity
are well enough defined to decide whether the measured
actions propagate at around 200'000 km/s (longitudinal wire
waves), at around 300'000 km/s (photons in the air) or
rather instantanously ('electrostatic force').
In any case, it is generally admitted that the situation
nearby an emitting dipole antenna does not agree with the
normal explanation and the drawings of waves peeling off,
which can be found in any textbook. So if we take seriously
logic we must conclude that this explanation is in principle
wrong.
If the electrostatic effects of an oscillating disc
propagated indeed at finite speed, longitudinal waves
similar to the ones propagating in wires would be a
consequence.
There is a fundamental difference between on the one
hand electrostatic and magnetic interactions and on the
other hand electromagnetic radiation:
After radiation having separated from a dipol, the dipol
is no longer affected by the radiation. Whether it is
absorbed by an antenna or not has no retroaction on the
emitting dipole. However, the induction of a current in
a neighbouring conductor has a retroaction on the dipole.
( translated from: http://members.lol.li/twostone/a3.html )
Gruss, Wolfgang
My previous two posts of this thread:
http://www.deja.com/=dnc/getdoc.xp?AN=532021977
http://www.deja.com/=dnc/getdoc.xp?AN=532263367
Frank Wappler
> Frank Wappler wrote:
> | (i.e. what he or you meant by)
> | "constant oscillation" and "meter" _at all_, trial by trial.
... if not by the conventional measurement procedures, i.e. by
the measurement procedures of SR: Einstein's calibration procedure
(which can be based on the exchange of roundtrip light signals),
and the associated distance definition (which is in turn
based on the results of sucessful calibration procedures, as
"c/2 * light_signal_roundtrip_interval;
if the beginning and end states of that interval, and the state
of reflecting the light signal, have been calibrated between
those two observers through Einstein's calibration procedure").
> So even if SR is assumed, clocks, rulers and simultaneity
> are well enough defined to decide whether the measured
> actions propagate at around 200'000 km/s (longitudinal wire
> waves), at around 300'000 km/s (photons in the air) or
> rather instantanously ('electrostatic force').
Yes, using the SR procedures one can measure relations between
various clocks ("simultaneity", i.e. pairwise calibration of
states/readings/proper_times; and subsequent calibration of intervals),
as well as relations between various ruler ends (measurement of
pairwise "distances");
and subsequent derivation of pairwise velocity, acceleration etc.
Note that measurements of instantaneous exchange of light signals,
i.e. zero light signal roundtrip intervals, imply _zero distance_
between those particular pairs of sources/emitters/clocks/ruler_ends
who exchange those particular signals, in those particular trials;
by the conventional procedure for determining "pairwise distance", above.
> In any case, it is generally admitted that the situation
> nearby an emitting dipole antenna does not agree with the
> normal explanation and the drawings of waves peeling off,
> which can be found in any textbook.
I'd be the first to admit that it can be difficult to reproduce in a
drawing the electromagnetic and other gauge fields nearby any particular
collection of about 10^24 or more charges, in any particular trial.
However, I don't know of disagreements with the conventional
explanation/preselected measurement procedure by which those fields
are conventionally determined in the first place, at least in principle:
namely via the Einstein procedures to measure coordinate relations
of charges/observers/clocks/ruler_ends wrt. each other,
and, taking those measurements as constraints, the subsequent
derivation of "the most probable" potential and fields
via the principle of stationary action.
Of course anyone is free to suggest other, preferebly reproducible,
measurement procedures; whose results might disagree with those
obtained by the conventional procedure, in any paricular trial,
given the same collected observations/data.
But _which_ "non-normal" measurement procedures, specificly?
And _are they_ as unambiguously reproducible as the Einstein procedures
and the principle of stationary action?, i.e. requiring no a priori
assumptions about any charges/observers/clocks/ruler_ends other than
_that_ they can exchange light signals and compare/count/do_math,
at least in principle?
> There is a fundamental difference between on the one
> hand electrostatic and magnetic interactions and on the
> other hand electromagnetic radiation:
> After radiation having separated from a dipol, the dipol
> is no longer affected by the radiation. Whether it is
> absorbed by an antenna or not has no retroaction on the
> emitting dipole. However, the induction of a current in
> a neighbouring conductor has a retroaction on the dipole.
What do you mean by "radiation having separated from"? -
how do you suggest to measure coordinates of "radiation" wrt. any
of the charges/observers/clocks/ruler_ends who constitute a "dipol"?
Also: if a pair of charges/observers/clocks/ruler_ends exchange a light
signal, is this not observable by all charges/observers/clocks/ruler_ends,
at least in principle, incl. by those two themselves?
Salut, Frank W ~@) R
z@z
| Wolfgang G. wrote:
| > There is a fundamental difference between on the one
| > hand electrostatic and magnetic interactions and on the
| > other hand electromagnetic radiation:
|
| > After radiation having separated from a dipol, the dipol
| > is no longer affected by the radiation. Whether it is
| > absorbed by an antenna or not has no retroaction on the
| > emitting dipole. However, the induction of a current in
| > a neighbouring conductor has a retroaction on the dipole.
|
| What do you mean by "radiation having separated from"? -
| how do you suggest to measure coordinates of "radiation" wrt. any
| of the charges/observers/clocks/ruler_ends who constitute a "dipol"?
Energy and momentum conservation are empirical facts at least
in the case of high-frequency radiation. If for instance an
atom emits a photon, the atom suffers a recoil impulse in the
opposite direction. The atom also loses the mass corresponding
to the emerging photon.
In the same way as there is an interaction between the emitting
atom and the emerging photon, there is an interaction between
an emitting dipole and the emerging radiation. When radiating,
the dipole loses energy which normally is compensated by an
energy supply. (Unlike real photons, QED 'photons' have neither
mass nor impulse, therefore a charged body can maintain its
electrostatic effect even if it emits many more QED 'photons'
than it absorbes.)
So whereas in the beginning there is an undeniable interaction
between an emitter and its raditation, there is certainly no
interaction between emitter and emitted radiation after the
latter having separated from the former, e.g. when the
radiation is absorbed by a radio antenna.
Gruss, Wolfgang
http://members.lol.li/twostone/E/physics1.html
bilge
>So whereas in the beginning there is an undeniable interaction
>between an emitter and its raditation, there is certainly no
>interaction between emitter and emitted radiation after the
>latter having separated from the former, e.g. when the
>radiation is absorbed by a radio antenna.
>
Physically, the separation means the "exchanged" photon satisfies
the condition q**2 = 0, i.e., the photon is real, not virtual and
therefore, is free to propagate without being tied to its emitter,
the antenna. Any form of the e-m field is carried by the photon, it's
just that the static or quasi static electric and magnetic fields
are what one sees as a result of virtual photon exchange (not on
mass shell) where the photon does not live independent of its
emitter.
Frank Wappler
> Frank Wappler wrote:
> | What do you mean by "radiation having separated from"? -
> | how do you suggest to measure coordinates of "radiation" wrt. any
> | of the charges/observers/clocks/ruler_ends who constitute a "dipol"?
You're addressing my questions more directly below.
Untill then let's establish some context:
> Energy and momentum conservation are empirical facts at least
> in the case of high-frequency radiation.
"Empirical facts" must be based on measurements, and therefore require
the selection of reproducible measurement procedures to begin with.
Measurements of energy and momentum (pairwise, of observers wrt. each other)
can be used to _determine_ which pairs exchanged which quantities
in the first place, and whether or to which extent some region is
"homogenious", "isotropic" and "closed".
> If for instance an atom emits a photon, the atom suffers a recoil
> impulse [momentum] in the opposite direction.
Don't forget to specify _how and wrt. whom_ "momentum" and "direction"
were determined, and with whom this photon was exchanged.
> The atom also loses the mass corresponding to the emerging photon.
I'm not sure what you mean by "the photon emerging" without defining
how to measure "coordinates of the photon" wrt. that atom;
AFAIK _exchange of a photon_ by a pair can be defined as
"exchange of _no_thing/charge/observer", but merely as
a transition between two states of one
correlated to a transition between two states of the other,
without reference to "coordinates of the photon".
You have a point:
Given measurements of energy and momentum of some particular observer A
(wrt. any other, B), one can express an invariant of A (wrt. any B):
"(energy_B( A )/c^2)^2 - (momentum_B( A )/c)^2", i.e. "mass_A^2".
Consequently a series of measurements of energy and momentum of A
(wrt. any other, B) can be used to determine the values of this invariant
throughout the course of those measurements.
Note that the measurements of "energy E" and "momentum p" are in turn
defined through measurements of pairwise coordinate relations "t" and "x",
E == hbar i d/dt(), and p == hbar/i d/dx.
> In the same way as there is an interaction between the emitting
> atom and the emerging photon, there is an interaction between
> an emitting dipole and the emerging radiation.
I consider "interaction" a relation between pairs of
atoms/dipoles/things/charges/observers (or systems thereof);
for instance _their_ exchange of photons, radiation, and/or light signals
_with each other_.
Atoms exchanging photons or dipoles exchanging radiation
are surely in some sense similar interactions.
> Unlike real photons, QED 'photons' have neither mass nor impulse,
AFAIK, QED distinguishes exchange of real, on-mass-shell photons;
and exchange of virtual, off-mass-shell photons.
Both notions are defined in terms of measured exchanged energy and momentum
(i.e. four-momentum, and the corresponding invariant mass).
> a charged body can maintain its electrostatic effect
> even if it emits many more QED 'photons' than it absorbes.
That seems implied in the notion of exchange of a "photon" as
"exchange of no_thing/charge" but merely correlated transitions.
> So whereas in the beginning there is an undeniable interaction
> between an emitter and its raditation, there is certainly no
> interaction between emitter and emitted radiation after the
> latter having separated from the former, e.g. when the
> radiation is absorbed by a radio antenna.
O.k. - IIUC by "interaction at the beginning" and
"interaction after separation" apparently you're referring to the
two transitions, between two states of the "dipole sender",
and between two states of the "radio antenna",
which toghether constitute the exchange of radiation, a light signal,
one or many photons.
Still, I consider "interaction _with_ radiation" misleading; instead,
there's "interaction between observers, between sender and antenna, etc.".
Return to what I thought was the main point:
Do you understand that Einstein's calibration procedure and the
associated distance definition allow this sender and this antenna
to determine their coordinate relations wrt. each other,
such that everyone else can understand their results?
(given sufficiently interactions/exchanges of light signals
with each other, as well as with certain auxiliary observers.)
How else do you suggest that they should measure their pairwise
coordinate relations, "simultaneity", "distance", "velocity", etc. at all?
Moataz H. Emam
Hi, I am not a part of this discussion but I cannot resist commenting on
the phrase:
"Energy and momentum conservation are empirical facts".
Not any more! Energy, momentum, angular momentum conservation laws have
been shown to be calculable consequences of time, translation and
rotation symmetries. This is known as Noether's theorem and has been in
print for about a hundred years since Emily Noether published this her
famous contribution to fundamental physics in the late 1800's. It is
taught in every Quantum or Classical field theory course in the world.
"z@z" wrote:
>
> Energy and momentum conservation are empirical facts at least
> in the case of high-frequency radiation. If for instance an
> atom emits a photon, the atom suffers a recoil impulse in the
> opposite direction. The atom also loses the mass corresponding
> to the emerging photon.
>
--
Moataz H. Emam
URL: http://www-unix.oit.umass.edu/~emam/
The Department of Physics and Astronomy
1129, Lederle Graduate Research Tower C,
University of Massachusetts, Amherst
e-mail : em...@physics.umass.edu
Tel. : (413) 545 0559
============================================
Charles Francis
<em...@physics.umass.edu> writes
>i, I am not a part of this discussion but I cannot resist commenting on
>the phrase:
>"Energy and momentum conservation are empirical facts".
>
>Not any more! Energy, momentum, angular momentum conservation laws have
>been shown to be calculable consequences of time, translation and
>rotation symmetries. This is known as Noether's theorem and has been in
>print for about a hundred years since Emily Noether published this her
>famous contribution to fundamental physics in the late 1800's. It is
>taught in every Quantum or Classical field theory course in the world.
Sometimes its taught very badly. Although I have the heading clearly in
my notes from lectures, and although I can prove the theorem, I hadn't
managed to put the two together.
--
Charles Francis
cha...@clef.demon.co.uk
Frank Wappler
> Energy, momentum, angular momentum conservation laws have
> been shown to be calculable consequences of time, translation
> and rotation symmetries.
By which measurement procedures are the extent of time, translation
and/or rotation symmetries determined experimentally in the first place?
(pairwise, between regions, and between trials)
Thanks, Frank W ~@) R
bilge
>Wolfgang G. wrote:
>
>> Unlike real photons, QED 'photons' have neither mass nor impulse,
>
>AFAIK, QED distinguishes exchange of real, on-mass-shell photons;
>and exchange of virtual, off-mass-shell photons.
>Both notions are defined in terms of measured exchanged energy and momentum
>(i.e. four-momentum, and the corresponding invariant mass).
>
Virtual photons can not only have mass, they can have the longitudinal
polarization states that result. There is only one difference between
a real photon and a virtual one: a real one satisfies q^2 = 0 and
may freely propagate.
>
>> a charged body can maintain its electrostatic effect
>> even if it emits many more QED 'photons' than it absorbes.
>
This doesnt make sense. Photons carry momentum. The electrostatic
effect is the momentum carried by the photons due to the charge
of an object. The photons do not carry charge and so cannot change
any feature related to charge. All a photon can do is change the
momentum of another charged body upon absorption. Any charged body
may absorb a photon. If the absorber and emitter are different
bodies, the result looks like a force because the momentum change
in the emitter has to equal the momentum change in the absorber.
Virtual photons do not exist independent of the emitter. If a
charged object emits a photon, it must either re-absorb it to
satisfy heisenberg, or another charged object must absorb it to
satisfy heisenberg. Since the exchange could occur by swapping
the roles of emitter/absorber, it is symmetric and should be
interpereted that way. In that sense, an object absorbs the same
number of virtual photons it emits.
bilge
>In article <37FCC03D...@physics.umass.edu>, Moataz H. Emam
>>Not any more! Energy, momentum, angular momentum conservation laws have
>>been shown to be calculable consequences of time, translation and
>>rotation symmetries. This is known as Noether's theorem and has been in
>>print for about a hundred years since Emily Noether published this her
>>famous contribution to fundamental physics in the late 1800's. It is
>>taught in every Quantum or Classical field theory course in the world.
>
>Sometimes its taught very badly. Although I have the heading clearly in
>my notes from lectures, and although I can prove the theorem, I hadn't
>managed to put the two together.
The simplest statement of noether's theorem is just that every to
symmetry of the lagrangian, there corresonds a conserved current.
If a lagrangian has no dependence under transformations of the
type (r,theta, phi) -> {r', theta', phi'), angular momentum must
be a conseverd quantity of that lagrangian. Linear momentum
follows from considering (x,y,z) -> (x', y', z'). qed follows
from considering pointwise changes to the phase of the electron
wavefunction psi -> psi*exp(i*phi(x)) and the good luck of the
photon being massless. You just normally dont use the term "conserved
current" when talking about conservation of (angular) momentum. The
truly elegant part of noether' theorem and terefore, field theory,
is that a symmetry principle is all that's needed to explain any
observable leaving the underlying explanation of nature conceptually
very simple, even if the details of a real calculation embodying
those concepts are exceedingly complex. Similarly, it allows you
to write a hamiltonian that combines the important pieces of a
real, intractable system into a tractable one you can apply field
theory to explain in limited circumstances. Cooper pairs in
BCS theory are the result of a dynamical symmetry of the
BCS hamiltonian.
bilge
>Moataz H. Emam wrote:
>
>> Energy, momentum, angular momentum conservation laws have
>> been shown to be calculable consequences of time, translation
>> and rotation symmetries.
>
>and/or rotation symmetries determined experimentally in the first place?
>(pairwise, between regions, and between trials)
>
Perform your experiment twice. The second time, rotate your
equipment 90-deg. Do you get the same result? Do this many
times to acheive good statistics. You should then be able
to quote a confidence level that suggests the likelyhood
that the theorem has some validity and that L is conserved.
Repeat the above except instead of rotating your equipment,
put it in another room. Do you get the same result? Repeat
statistical analysis. Increase confidence level that noether's
theorem is true and that momentum is conserved. Since energy
conservation is built into the relativistic concept of momentum,
by choosing a frame of reference, you get conservation of 3-momentum
and conservation of energy. You really cheated a little, but
you can remedy the situation by performing your second experiment at
a fixed velocity relative to the first.
Repeat for every symmetry you can find to test.
Harry H Conover
: Frank Wappler, thank you very much for the translated quotes.
:
: These quotes show that HEINRICH HERTZ has indeed found in his
: experiments that ELECTROSTATIC effects propagate INSTANTANOUSLY
: and NOT at c as generally assumed.
This will come as a terrible shock to those who have been involved
in the design of very successful electromagnetic wave (r.f) based
communications systems and equipment for the past 80+ years.
Also, James Clerk Maxwell must be turning over in his grave on
learning this rather remarkable fact! ;-)
Harry C.
Frank Wappler
> Frank Wappler [wrote]:
> > AFAIK, QED distinguishes exchange of real, on-mass-shell photons;
> > and exchange of virtual, off-mass-shell photons.
> > Both notions are defined in terms of measured exchanged energy and
> > momentum (i.e. four-momentum, and the corresponding invariant mass).
> There is only one difference between
> a real photon and a virtual one: a real one satisfies q^2 = 0
Precisely; where q denotes the four-momentum that has been transferred
between the two charges/observers who have exchanged this photon.
> and may freely propagate.
What do you mean by "a photon propagating", "freely" ?
How would you measure "coordinates of a photon" wrt. other observers?
> If a charged object emits a photon
Note that this by itself is kinematically forbidden, at least for
real photons. Instead one considers _exchange_ of photons by pairs
(of not necessarily distinct charges/observers).
> Since the exchange could occur by swapping the roles of emitter/absorber,
... yes, surely emitter and absorber can observe each other, mutually ...
> it is symmetric and should be interpreted that way.
The conventional measurement procedures, which are based
on light_signal_roundtrips obviously use the fact that this symmetry
is not perfect at all:
if I see the deer, the deer has thereby not necessarily
seen me in turn already
(unless the roundtrip interval and corresponding distance
is zero, of course);
observer A's state "Ax: I've observed B in state B5" does _not require_
or imply that this state of observer B is in turn
"B5: I've observed A in state Ax, observing B5";
but _if_ this were found, then A and B would be able to conclude
zero light signal roundtrip interval wrt. each other,
in this particular trial and pair of states.
Otherwise there _may_ well occur state
"B9: I've observed A in state Ax, observing B5",
from which observer B can conclude that state B9 is _after_ state B5.
(That's a way by which an observer can _order_ her/his/its own
set of states in the first place.)
> In that sense, an object absorbs the same number of virtual photons
> it emits.
That's obvious for photons which _one_ particular object/charge/observer
emits/absorbs/exchanges only wrt. him/her/it_self_.
But otherwise I fail to find sense in your point.
Consider a pair of distinct objects/charges/observers who exchange
just one (virtual) photon.
Did either one emit and absorb the same number?
Or are you suggesting that this example is not possible or ill-defined?
Tom Roberts
> [pretty good description of photon absorbtion/emission]
> In that sense, an object absorbs the same
> number of virtual photons it emits.
Except for one "little" thing -- in a basis where individual photons
have well-defined 4-momenta, the number operator does not have a well-
defined value, and you cannot count them! In a basis where the number
operator has a well-defined value, individual photons do not have
well-defined 4-momenta! This is intimitely related to the fact that
photons are indistinguishable Bosons, and to the necessity to
symmetrize the wavefunction over Bosons and anti-symmetrize over
Fermions -- in a perturbative approximation this intermixes all the
Bosons/Fermions in all of the different diagrams....
If one _really_ tries to take into account _all_ of the properties
of photons in QED, the discussion gets so convoluted and complicated
that it is essentially useless....
There seems to be a Heisenberg uncertainty relationship
between correctness and understandibility (:-)).
Tom Roberts tjro...@lucent.com
Tom Roberts
> "Energy and momentum conservation are empirical facts".
> Not any more!
Sure they are _still_ "empirical facts" (i.e. a summarization of many
experimental observations). Nothing you said disputes or changes the
zillions of observations which have been made.
> Energy, momentum, angular momentum conservation laws have
> been shown to be calculable consequences of time, translation and
> rotation symmetries.
Yes, indeed. Noether's theorems are an important and versatile aspect
of Lagrangian field theories. But IMHO the impact is precisely the
opposite to what you claim -- these theorems do not really place the
conservation laws on a firm theoretical foundation. The conservation
of energy and momentum are, indeed, established experimentally;
Noether's theorem then NARROWS THE SEARCH for theories which accurately
correspond to the experimental results, in a natural and _compelling_
way.
Remember, please, that if you claim that symmetries provide a theoretical
justification for the conservation laws, then you have no justification
for selecting just those theories which do this. Note that your claim
quoted above is too strong -- conservation laws are "calculable
consequences" of symmetries _ONLY_ in Lagrangian field theories. Noether's
theorems are an important reason why that is the only class of fundamental
theories we use today....
Tom Roberts tjro...@lucent.com
Frank Wappler
> Frank Wappler [wrote]:
> > Moataz H. Emam wrote:
> > > Energy, momentum, angular momentum conservation laws have
> > > been shown to be calculable consequences of time, translation
> > > and rotation symmetries.
> > By which measurement procedures are the extent of time, translation
> > and/or rotation symmetries determined experimentally in the first place?
> > (pairwise, between regions, and between trials)
> Perform your experiment twice.
_Which experiment_?
And, if the results of those two trials are to be compared,
is the experimental procedure unambiguously reproducible,
from one trial to the other?
> The second time, rotate your equipment 90-deg.
Can you please specify this procedure?
I don't know how to measure any non-zero value of "rotation"
of some particular equipment wrt. _itself_, for instance.
Part of this difficulty may be resolved by conducting _two_
independent experiments, involving two collections of equipment.
Then: How do you determine whether a pair of equipment is
"rotated 90-deg." wrt. each other?
(Also, the reproducibility requirement of the experimental procedure
remains in effect, of course; indeed, it is thereby emphasized.)
> Do you get the same result?
Of course not; from distinct trials one obtains distinct results.
Before those various distinct results may be compared and one may
determine whether or to which extent they are equal, it remains to be
seen if the experimental procedure which you still have to specify
is reproducible enough to yield a unique and unambiguous result value
in each particular trial at all.
> Do this many times to achieve good statistics.
Sure; with the caveat about first of all requiring a reproducible
measurement procedure.
> You should then be able to quote a confidence level that suggests the
> likelyhood that the theorem has some validity and that L is conserved.
??? Nöther's theorem is a mathematical theorem, AFAIU.
Everyone (at least in principle) can reproduce it a priori with complete
confidence and without reference to any experimental results.
My question was _how to determine whether or not_ some particular
symmetry holds and (equivalently) some particular current is conserved,
in some particular set of trials.
Given a reproducible experimental procedure (which you have yet to
specify), and given sufficiently many trials/observations collected
in those trials in order to derive results by the selected procedure,
I can (at least in principle) determine a confidence level for every
specific prediction/hypothesis about isotropy or deviation from isotropy,
in those particular trials, for this particular experimental procedure.
> Repeat the above except instead of rotating your equipment,
> put it in another room. [...]
> Since energy conservation is built into the relativistic concept
> of momentum, by choosing a frame of reference,
Please specify how to "choose a frame of reference".
> you get conservation of 3-momentum and conservation of energy.
> You really cheated a little, but you can remedy the situation
> by performing your second experiment at a fixed velocity relative
> to the first.
Please specify how to determine the value of "velocity" of two
experiments (i.e. two collections of equipment) wrt. each other.
Charles Francis
the conservation laws, and then find that the Lagrangian formulation
produces them, so they are empirical. But it is possible to go a step
deeper and formulate field theory, again on observational principles,
but in such a way that neither energy/momentum nor the Lagrangian is a
basic assumption of the theory. It still follows from the homogeneity of
the model that energy/momentum is conserved
http://xxx.lanl.gov/abs/physics/9905058
A Theory of Quantum Space-time
--
Charles Francis
cha...@clef.demon.co.uk
bilge
>_Which experiment_?
>And, if the results of those two trials are to be compared,
>is the experimental procedure unambiguously reproducible,
>from one trial to the other?
>
You're missing the point. Do any experiment. Do as many different
ones as possible. If you conclude that no experiment you can perform
will have a preferred orientation in space, then through noether's
theorem you can conclude that any experiment you perform also
conserves angular momentum (to the extent that you account for
all of the pieces), and that if any angular momentum turns
up missing in any experiment whatsoever, you should look for the
missing angular momentum, before announcing the demise of the
conservation law. It inspires confidence in postulating a neutrino
as more than an ad hoc remedy, when you need it, for example.
================================================================
>Can you please specify this procedure?
>I don't know how to measure any non-zero value of "rotation"
>of some particular equipment wrt. _itself_, for instance.
>
That's the point. It's completely irrelavent which way your equipment
points. You arent concerned wrt to itself. You get to use the result
because it's always true.
>
>Of course not; from distinct trials one obtains distinct results.
>
It really stretches the colloquial use of "experiment" to regard it as
synonymous to a distinct trial, despite that being the case in a strict
mathematical sense. Experimentalists typically say experiment to refer
to a measurement as a whole. For example, I dont typically refer to
a lifetime measurement as 10 sets of 10,000 experiments, but rather
an experiment with 10 spectra, each containing 10,000 events with
the resulting half-life of xxx+/-y seconds. This, I can add to any
other complete measurement. The "of course not" only applies to
taking, for example, a count in channel 599 and giving it to joebob
in timbuktu for comparison. Sure. That's not only obviously wrong,
it doesnt even make sense, but I was using "experiment" in the
colloquial sense of the whole thing. Call me old-fashioned...
>My question was _how to determine whether or not_ some particular
>symmetry holds and (equivalently) some particular current is conserved,
>in some particular set of trials.
Pick angular momentum. Choose an experiment. It doesnt matter what it
is because, if you can find ANY experiment whatsoever that gives you
different results by merely facing a different direction, noether's
theorem would conclude that you cant expect angular momentum to be
conserved as a general rule. It's obvious a positive proof cant
be done here any more than for any other theorem. So, assuming you
believe that overall, total angular momentum is conserved, you can
shrink the extent of your system to be as isolated as you can
be certain you have all of the pieces to add and obtain a total.
A classic example would be knowing the missing angular momentum in
beta decay had to come from an unobserved particle because no one
was willing to believe angular momentum wasnt conservered or that
there was anything that left room for any other way to account for
it. Another would be the identification of spin as an angular momentum,
despite the fact that particles do not "spin" in the ordinary sense of
the word. The dirac hamiltonian doesnt commute with L. It commutes with
L+S. Rather than give up a conservation law, intution suggested the
additional degree of freedom found in the spinors is an angular
momentum.
If this isnt related to what you asked, then I'm not clear on what it
is you are asking. I get the impression that I'm addressing something
I interpereted in a way you didnt intend and I'm addressing the
wrong thing here.
bilge
>z@z (z...@z.lol.li) wrote:
>: These quotes show that HEINRICH HERTZ has indeed found in his
>: experiments that ELECTROSTATIC effects propagate INSTANTANOUSLY
>: and NOT at c as generally assumed.
>
>This will come as a terrible shock to those who have been involved
>in the design of very successful electromagnetic wave (r.f) based
No pun intended, I presume?
bilge
>What do you mean by "a photon propagating", "freely" ?
>How would you measure "coordinates of a photon" wrt. other observers?
>
It isnt tied to the source from which it was emitted. One that
doesnt leave its emitter off mass-shell and other equivalent
statements.
Since the only means to determine its coordinates is by observing
it (and thus destroying it in the process), I'd have to define
its coordinates by the point of observation or by inference from
the point of origin and a density matrix containing whatever
information there is to be had wrt things that might render
the probability of finding it along some directions, less likely
than others (like a slit). However, I'm not going to suggest
it has coordinates beyond what a probabilty amplitude buys
you. Obviously, there's no frame to obtain the photon's idea
of where it is (I've always wondered what the world looks
like to a photon).
>Note that this by itself is kinematically forbidden, at least for
>real photons. Instead one considers _exchange_ of photons by pairs
>(of not necessarily distinct charges/observers).
>
Sure.
>if I see the deer, the deer has thereby not necessarily
>seen me in turn already
However, murphy's law states the deer then will see you
and you wont necessarily see that it moved before pulling
the trigger and missing.
>(unless the roundtrip interval and corresponding distance
>is zero, of course);
>That's obvious for photons which _one_ particular object/charge/observer
>emits/absorbs/exchanges only wrt. him/her/it_self_.
>
>But otherwise I fail to find sense in your point.
>Consider a pair of distinct objects/charges/observers who exchange
>just one (virtual) photon.
>Did either one emit and absorb the same number?
>Or are you suggesting that this example is not possible or ill-defined?
I'm suggesting just that. The physical situation has to include
both possibilities since it isnt possible to distinguish between
the two. Actually, you have to include more. If you have identical
particles, you cant even say incoming particle line goes with
which outgoing line. I've always taken the concept of distinguih-
ability to be literal fact: If something cannot be observed in
principle, it isnt real or physically meaningful to consider and
attempting to do so "as if it were to see what happens", from the
looks of some of the more creative posts I've seen, leads to
pleas to support research to extract free energy from little
rotating particles in the vacuum :)
I'm not sure it makes sense to enumerate them at all, since a
proper count requires the infinity of diagrams.
bilge
>In the standard Lagrangian formulation this is correct. Really we know
>the conservation laws, and then find that the Lagrangian formulation
>produces them, so they are empirical. But it is possible to go a step
>deeper and formulate field theory, again on observational principles,
>but in such a way that neither energy/momentum nor the Lagrangian is a
>basic assumption of the theory. It still follows from the homogeneity of
>the model that energy/momentum is conserved
>
I think the point was that it's impossible to do any experiment
which proves any theorem. You can only perform experiments and
look for a contradiction. Failing to find one, the best you can
say is that you believe the theorem because you've failed to
prove it false along with the fact that it seems reasonable. Another
theorem consistent with all observed results would still be in
the running. You only differentiate by showing which are wrong.
Frank Wappler
> Frank Wappler [asked]:
> > What do you mean by "a photon propagating", "freely" ?
> > How would you measure "coordinates of a photon" wrt. other observers?
> I'd have to define its coordinates by the point of observation
How would you determine the coordinates of emission and reception
of some particular photon, wrt. each other?
> or by inference from the point of origin and a density matrix
> containing whatever information there is to be had wrt things that
> might render the probability of finding it along some directions, less
> likely than others (like a slit).
How is such density matrix information obtained in the first place?,
if not from measurements of coordinates of emission and reception alone;
perhaps together with the expectation that
"the most probable potential of some slit or any other thing/observer
to render the probability of finding a photon along some directions
doesn't change a lot, soon".
> However, I'm not going to suggest it has coordinates beyond
> what a probabilty amplitude buys you.
Thanks; I had been concerned that by "a photon propagating" you implied
that one could _measure_ coordinates of a photon other than
the coordinates of emission and reception.
Still, are you implying that exchange of a photon were not
_completely_ described by emission and reception?:
> the only means to determine its coordinates is by observing
> it (and thus destroying it in the process)
What "it" do you suggest is "destroyed in the process of observation"?
AFAIK, the exchange of a photon is only _established_ in the first place
by the receiver observing the transition between states of the emitter.
> [A photon that propagates "freely" ...] doesnt leave its emitter
> off mass-shell
"Off mass-shell" wrt. _whom_?
> > [bilge/serling wrote:
> > > Since the exchange could occur by swapping the roles of
> > > emitter/absorber, it is symmetric ...
> > The conventional measurement procedures, which are based
> > on light_signal_roundtrips obviously use the fact that
> > this symmetry is not perfect at all:]
> > if I see the deer, the deer has thereby not necessarily
> > seen me in turn already
> However, murphy's law states the deer then will see you
Please note the distinction (asymmetry) between "seen already", and
"then will see". This distinction vanishes (only) if
> > [the roundtrip interval and corresponding distance is zero]
(Also, this distinction is defined whether Murphy's law holds, or not,
in any particular trial.)
> > Consider a pair of distinct objects/charges/observers who exchange
> > just one (virtual) photon.
> > Did either one emit and absorb the same number?
> > Or are you suggesting that this example is not possible or ill-defined?
> I'm suggesting just that. The physical situation has to include
> both possibilities since it isnt possible to distinguish between the two.
They or anyone else might use the distinction indicated above
(and in more detail in the preceding post).
But of course anyone is free to ignore distinctions, too.
> Actually, you have to include more. If you have identical particles,
Well - I had been asking about distinct objects/charges/observers.
I don't know how otherwise to determine coordinate relations,
through the Einstein procedures anyways.
> you cant even say [which] incoming particle line goes with
> which outgoing line.
Right - distinct Feynman diagrams which aren't being distinguished
by what's observed/exchanged (and which are therefore only
"potentially distinct") are described as "interfering with each other".
Though one can determine "the most probable contribution" of each,
along with the determination of "the most probable potential"
(i.e. coordinates of potential slits, walls, etc.) in the region
containing the given set of trials.
> I'm not sure it makes sense to enumerate them at all
I'm not sure why the exchange of _one_ (virtual) photon
shouldn't be described as interference of many diagrams.
Regards, Frank W ~@) R
p.s.
> I've always taken the concept of distinguishability to be literal fact:
> If something cannot be observed in principle, it isnt real or physically
> meaningful to consider
I've always found the inverse consideration more interesting:
An observation collected by an invidual observer is surely real
and may be meaningful to that individual;
but for statements to meaningfully describe reality as agreed upon
by _all_ observers, at least in principle, they must be derived
from individual observations by reproducible measurement procedures.
Measurements can (or ought to) be unambigously copied,
communicated and reproduced/understood;
individual observations, and individuals themselves, can not.
ralph sansbury
z@z wrote in message <7t589r$t28$1...@pollux.ip-plus.net>...
>Frank Wappler, thank you very much for the translated quotes.
>
>experiments that ELECTROSTATIC effects propagate INSTANTANOUSLY
>and NOT at c as generally assumed.
Could you describe the problematic Hertz experiment briefly. I still dont
see exactly what he did.
As to the possible reasons: Something more relevant than the usual
inappropriate mantras from the usual suspects is the Wheeler Feynman theory
of advanced and retarded potentials or the improved version as follows:
The source of the radiation produces a repeated oscillation sequence of
instantaneous forces at a distance on the receiving antenna wire. Each force
in the sequence acts on the free electrons and on the interior of the atomic
nuclei and of the free electrons.
A transverse polarization of charge is produced by each such force inside
the atomic nuclei at the same time the free electrons are made to move in
the direction of this applied force. This transverse polarization of charge
is what produces the so called magnetic force. The next in the oscillatory
sequence of instantaneous forces at a distance produces the same sort of
effect but now of a different magnitude.
This causes a change in the transverse force and this change in the
transverse force produces a longitudinal polarization of charge inside other
atomic nuclei and a force field in the opposite direction of the
instantanous force at a distance.
After many oscillations the field resulting form the longitudinal
polarization of charge inside the atomic nuclei becomes dominant.
The delay before this field becomes dominant is given by the speed of
light and the distance from the source. And the mechanism involves the
elasticity of charge polarization inside the atomic nuclei which is the true
significance of the speed of light.
see http://www.bestweb.net/~sansbury
>
>Interference effects between waves in a wire orginating from the
>center of a brass disc and the electrostatic effects of the disc
>can be measured. If oscillations of 35.7 Megahertz are used and
>the speed of the wire waves is 200 000 km/s, we get a wave length
>of 5.6 meters. If electrostatic effects propagate instantanously,
>after 5.6 m, 11.2 m, 16.8 m, ... the wire must be in phase with
>the electrostatic effect of the disc.
>
>
>A simple tape measure is enough to determine at which distances
>from the emitter the interference changes sign.
>
>In any case, it would make sense to repeat this crucial experiment.
>
>
>Wolfgang Gottfried G.
>
>
>Previous relevant posts:
>http://www.deja.com/=dnc/getdoc.xp?AN=530719931
>http://www.deja.com/=dnc/getdoc.xp?AN=531225851
>http://www.deja.com/=dnc/getdoc.xp?AN=531506436
>http://www.deja.com/=dnc/getdoc.xp?AN=531614175
>
>
Frank Wappler
> If this isnt related to what you asked, then I'm not clear on what it
> is you are asking.
Thanks - I find your replies related and relevant to the question I had
asked in reply to Moataz H. Emam,
Frank Wappler [wrote]:
. By which measurement procedures are the extent of time, translation
. and/or rotation symmetries determined experimentally in the first place?
and I've asked follow-up questions in this post,
about what of your reply I don't understand.
> Pick angular momentum. Choose an experiment. It doesnt matter what it is
Fine - I'd select a _reproducible_ experimental procedure, in order to
compare the results obtained in various trial to each other.
> if you can find ANY experiment whatsoever that gives you
> different results by merely facing a different direction, noether's
> theorem would conclude that you cant expect angular momentum to be
> conserved as a general rule.
More specificly, and quite independent of anyone's expectations,
if different results have been obtained by merely facing a different
direction and anisotropy is thereby indicated in those particular trials,
for the region containing those trials,
then Nöther's theorem would allow to conclude that angular momentum
_was not_ conserved, in those particular trials, in the region containing
those trials.
It remains my initial question, for the picked case:
How and wrt. whom does one determine "direction" in the first place,
and whether or to which extent any pair of experiments
"face in different direction"?
> assuming you believe that overall, total angular momentum is conserved
> you can shrink the extent of your system to be as isolated
Sure; but I'd like to know how to _measure_ angular momentum,
trial by trial, and thereby to determine whether or to which extent
some particular system _is_ "closed" (wrt. angular mometum).
> A classic example would be knowing the missing angular momentum in
> beta decay
How and wrt. whom was angular momentum measured, in order for
the comparison of resulting values (before and after the decay,
I suppose) to be meaningful?
> Another would be the identification of spin as an angular momentum,
> despite the fact that particles do not "spin" in the ordinary sense of
> the word.
> The dirac hamiltonian doesnt commute with L. It commutes with L+S.
How are the Dirac Hamiltonian, L and L+S to be measured, separately,
to begin with?
If you understand them as defined in terms of coordinate relations,
"x_mu", and the derived operator "d/dx_mu()", etc.
then how and wrt. whom are _those_ to be measured?
Also, if the Dirac Hamiltonian (and/or Lagrangean) happen to commute
with L+S, then measurements of L+S may be useful for _counting_
certain particles.
> Rather than give up a conservation law, intution suggested the
> additional degree of freedom found in the spinors is an angular momentum.
Given the fact that particles don't seem to "spin" in the ordinary
sense of the word, that suggestion may have sprung from
convenience and opportunity, instead intuition ...
Regards, Frank W ~@) R
p.s.
> > [...] from distinct trials one obtains distinct results.
> > [... those various distinct results may be compared and one may
> > determine whether or to which extent they are equal]
> I dont typically refer to a lifetime measurement as 10 sets of
> 10,000 experiments, but rather an experiment with 10 spectra,
> each containing 10,000 events with the resulting half-life of
> xxx+/-y seconds. This, I can add to any other complete measurement.
Sure, you're free to define "one complete trial" as you see fit,
that's part of selecting measurement procedures a priori.
> taking, for example, a count in channel 599 and giving it to joebob
> in timbuktu for comparison [...] That's not only obviously wrong,
> it doesnt even make sense
In which sense is a comparison with, say, the count in channel 598
any less wrong than that, or a comparison with some other count
obtained by channel 599?
If not at least counts/numbers can be unambiguously understood
and reproduced by _anyone_, at least in principle, then ...
what else should one try to communicate instead?
Dale Woodside
>
> z@z (z...@z.lol.li) wrote:
> : Frank Wappler, thank you very much for the translated quotes.
> :
> : These quotes show that HEINRICH HERTZ has indeed found in his
> : experiments that ELECTROSTATIC effects propagate INSTANTANOUSLY
> : and NOT at c as generally assumed.
>
> in the design of very successful electromagnetic wave (r.f) based
>
> Also, James Clerk Maxwell must be turning over in his grave on
> learning this rather remarkable fact! ;-)
>
> Harry C.
A related scalar potential instantaneous propagation
curiosity is discussed nicely in:
O. L. Brill and B. Goodman, "Causality in the Coulomb Gauge."
Am. J. Phys. _35_, 832 (1967).
J. D. Jackson, Classical Electrodynamics, (John Wiley & Sons,
New York, 1975, 2nd edition) pp. 220-223.
Result: Causality is maintained...
Dale Woodside
Macquarie Univ.-Sydney
Charles Francis
s.net>, bilge <ser...@radioactivex.lebesque-al.net> writes
obvious as it were. You can produce theorems based on the principles of
what is done in measurement.
If, in addition, you are not prepared to accept ontological infinity
then Leibniz argument of infinite interpolations of finite data does not
apply.
--
Charles Francis
cha...@clef.demon.co.uk
Steven B. Harris
writes:
> There seems to be a Heisenberg uncertainty relationship
> between correctness and understandibility (:-)).
Or as Bohr liked to say, between truth and clarity. Which is why
those science journalists have such a devil of a time, don't you know.
z@z
| Harry H Conover wrote:
| > : These quotes show that HEINRICH HERTZ has indeed found in his
| > : experiments that ELECTROSTATIC effects propagate INSTANTANOUSLY
| > : and NOT at c as generally assumed.
| >
| > This will come as a terrible shock to those who have been involved
| > in the design of very successful electromagnetic wave (r.f) based
| > communications systems and equipment for the past 80+ years.
| >
| > Also, James Clerk Maxwell must be turning over in his grave on
| > learning this rather remarkable fact! ;-)
| A related scalar potential instantaneous propagation
| curiosity is discussed nicely in:
|
| O. L. Brill and B. Goodman, "Causality in the Coulomb Gauge."
| Am. J. Phys. _35_, 832 (1967).
|
| J. D. Jackson, Classical Electrodynamics, (John Wiley & Sons,
| New York, 1975, 2nd edition) pp. 220-223.
|
| Result: Causality is maintained...
A quote from the German translation of Jackson's 2nd edition:
"Am Rande sei auf eine Besonderheit der Coulomb-Eichung
hingewiesen. Elektromagnetische Wellen breiten sich bekanntlich
mit endlicher Geschwindigkeit aus. Gleichung (6.45) besagt
jedoch, dass sich das skalare Potential momentan im ganzen Raum
"ausbreitet". Das Vektorpotential dagegen genügt der Wellen-
gleichung (6.52), die die endliche Ausbreitungsgeschwindigkeit
c enthält. Auf den ersten Blick erscheint es schwierig, dieses
offensichtlich unphysikalische Verhalten zu umgehen."
This "obviously unphysical behaviour" is yet inherent in Maxwell's
equations. Despite Maxwell's contradictory claim, the possibility
to derive e.m. radiation does not entail that electrostatic
effects (described by the first Maxwell equation) propagate at
the same speed as the radiation.
And this first Maxwell equation entails that it is possible to
transmit information instantanously. The change in charge of
a body affects its neighbourhood instantanously. In the same
way, the induction effect is an instantanous effect. If this
effect is used to transmit information over a distance of 3 m
no time delay of 10 nanoseconds is predicted by the most
obvious interpretation of Maxwell's equations.
Maxwell's 'displacement current' which is assumed to propagate
at c is also an erroneous concept. The effects currently
explained by displacement currents can be better explained by
the first Maxwell equation which states that the net charge
inside a closed surface can always be determined by its effect
on the surface. The movements of charges affect distant surfaces
instantanously, otherwise the first Maxwell equation would be
valid only in static situations and could not be used to derive
e.m. radiation.
In any case, Jackson's section on "scalar potential instantanous
propagation" shows that instantanous e.m. effects not only have
to be explained away on the experimental side but also on the
theoretical side.
Wolfgang Gottfried G.
http://members.lol.li/twostone/E/physics1.html
Frank Wappler
> A quote from the German translation of Jackson's 2nd edition:
> "Am Rande sei auf eine Besonderheit der Coulomb-Eichung
> hingewiesen. Elektromagnetische Wellen breiten sich bekanntlich
> mit endlicher Geschwindigkeit aus. Gleichung (6.45) besagt
> jedoch, dass sich das skalare Potential momentan im ganzen Raum
> "ausbreitet". Das Vektorpotential dagegen genügt der Wellen-
> gleichung (6.52), die die endliche Ausbreitungsgeschwindigkeit
> c enthält. Auf den ersten Blick erscheint es schwierig, dieses
> offensichtlich unphysikalische Verhalten zu umgehen."
This corresponds to my copy of Jackson's 2nd edition (p. 222 and 223):
"In passing we note a peculiarity of the Coulomb gauge. It is well
known that electromagnetic disturbances propagate with finite speed.
Yet (6.45) indicates that the scalar potential "propagates"
instantaneously everywhere in space. The vector potential, on the
other hand, satisfies the wave equation (6.52), with its implied
finite speed of propagation c. At first glance it is puzzling how
this obviously unphysical behavior is avoided."
which is stated with the note
"See O. L. Brill and B. Goodman, Am. J. Phys. 35, 823 (1967)
for a detailed discussion of causality of the Coulomb gauge."
After some calculation, they in turn obtain the unsurprising result
that the E == -d/dx( Phi ) - 1/c d/dt( A ) is _still_ the solution
of a wave equation, indicating "propagation with finite speed".
The scalar and the vector potentials themselves _don't_ have
direct physical relevance;
_that's why_ there is a gauge freedom in the first place when
expressing Maxwell's equations in terms of potentials A and Phi,
and that's why the mathematical consequences of the chosing
the Coulomb gauge don't constitute a physical puzzle.
(Note that even for the remarkable Aharanov-Bohm effect
the physically relevant quantity is _magnetic flux_,
and not for instance "the vector potential itself".)
> This "obviously unphysical behaviour" is yet inherent in
> Maxwell's equations.
Obviously not so for the quantities E, D, B, and H in terms of which
Maxwell's equations (6.28) are stated;
but merely after rendering them in terms of quantities that are not
"obviously physical" themselves anyways, namely the potentials A and Phi.
(Not to be misunderstood:
the fact that Maxwell's equations _allow_ themselves to be rendered
with such gauge freedom is itself physically relevant, of course.)
> [The] first Maxwell equation entails that it is possible to
> transmit information instantanously
... _IF_ one could make or destroy charge.
But the notions of what constitutes/how to count "charge",
and directly related, what constitutes/how to recognize
"transmission of information" preclude this by _definition_.
Of course you're free to apply (the formalism of) Maxwell's equations
to describe relations between entities that/who are _not_ charges.
Though then it may be difficult or impossible for others to obtain
any unambiguous, reproducible, meaningful information;
IOW, it may be impossible to _measure_ what you might wish to describe.
Tom Roberts
> And this first Maxwell equation entails that it is possible to
> transmit information instantanously. The change in charge of
> a body affects its neighbourhood instantanously.
Not true. You cannot create or destroy charge, because the
electromagnetic current is conserved (div J = 0) -- that's a direct
consequence of Maxwell's equations.
> In the same
> way, the induction effect is an instantanous effect.
Ditto.
Tom Roberts tjro...@lucent.com
bilge
>How would you determine the coordinates of emission and reception
>of some particular photon, wrt. each other?
I suppose it depends upon the circumstances. If you look
at a radioactive decay for example which emits a gamma
and beta:
-------
\ e-
\
-----
| gamma
|
-----
I know where the radioactive material is located, I can see the
beta decay occur, I can detect a gamma with a detector and know
it's correlated with the stuff located in the target.
>How is such density matrix information obtained in the first place?,
>if not from measurements of coordinates of emission and reception alone;
>perhaps together with the expectation that
>"the most probable potential of some slit or any other thing/observer
>to render the probability of finding a photon along some directions
>doesn't change a lot, soon".
>
>> However, I'm not going to suggest it has coordinates beyond
>> what a probabilty amplitude buys you.
>
>Thanks; I had been concerned that by "a photon propagating" you implied
>that one could _measure_ coordinates of a photon other than
>the coordinates of emission and reception.
>
Not I. I believe it when quantum mechanics says you cant measure
certain things, even in principle. That's why I suggested a
density matrix. It contains all the information there is to know
for a given situation.
>Still, are you implying that exchange of a photon were not
>_completely_ described by emission and reception?:
>
No. I'm really not trying to imply too much about the process beyond
trying to emphasize any symmetry that, if absent,would suggest
fundamentally different roles played by the emitter and absorber in
the virtual case. The analogy shouldnt be taken too seriously as
a literal occurence. I was more interested in making the symmetry
explicit, not suggesting you can literally assume two photons do
precisely as I suggested. That's one of those things you cant measure,
cant ever know and only represents a small part of the whole
process.
>What "it" do you suggest is "destroyed in the process of observation"?
>AFAIK, the exchange of a photon is only _established_ in the first place
>by the receiver observing the transition between states of the emitter.
>
I dont undertand your statement. Consider a transition that
emits a photon, A->B + gamma. The photon doesnt have an
existence which depends upon B. The photon is on mass shell.
If I observe it, certainly no one else will. I can only observe
it if it creates some disturbance I can measure. In the process,
the photon gets absorbed by something along the way. I dont
see what your statement means in this context, for example.
Maybe you could use this or a similar context to clarify it for me.
>> [A photon that propagates "freely" ...] doesnt leave its emitter
>> off mass-shell
>
>"Off mass-shell" wrt. _whom_?
>
If you look at just one piece of the exchange process:
| |
'| |
' | |
' | | This photon is clearly not propagating freely
' | |
' | |
'| |
| |
e
\ /
' \ / Neither is the one at A.
' \ B /
' /''''''\
A' / \
/ \
e
e
' |
' |
' | If the momentum and energy at B are such that
'|A the photon at A is kinematically able to meet
| B the condition q^2 = 0, then it isnt bound by
|''''''''' any physical requirement to be re-absorbed.
e it prpopagates. If this isn't satisfacrory, I'm
afraid I'm out of ways in which I intend to make
an attempt to explain it. Further attempts to
play semantic games with quantum effects is bound
to add more confusuion than it eliminates and
goes against the quantum nature of an observable.
q^2 = 0, should be sufficient to describe a
propagating photon.
If there were no difference between a virtual photon and one
that propagates, you'd have no fermi sea to work with as a
vacuum state.
>
>They or anyone else might use the distinction indicated above
>(and in more detail in the preceding post).
>But of course anyone is free to ignore distinctions, too.
>
>"potentially distinct") are described as "interfering with each other".
>Though one can determine "the most probable contribution" of each,
>along with the determination of "the most probable potential"
>(i.e. coordinates of potential slits, walls, etc.) in the region
>containing the given set of trials.
>
The only parts I consider to bear a resemblece to reality are those
subsets that produce observables. There are two many problems
with suggesting it's possible to guess what is unobservable in
principle as a mechanism for anything.
>
>I'm not sure why the exchange of _one_ (virtual) photon
>shouldn't be described as interference of many diagrams.
>
I thought that was basically what a feynman diagram does. It provides
an intuitive way to dissect a complex interaction into tractable
calculations which have physical interperatations. One photon line
represents both moeller and bhabba scattering diagrams, right?
It doesnt represent just one though, it represents them all. I was
merely suggesting that the symmetry of the exchange be retained in
any conceptual description in stating both particles play both roles
in the exchange process. If you dont, the obvious question that
someone is bound to ask from your choice of a single photon going from
A to B as reality is "why doesnt it go from B to A". I dont think you
were really suggesting nature makes such distinctions.
Frank Wappler
> Wolfgang Gottfried G./z@z wrote:
> > [The] first Maxwell equation entails that it is possible to
> > transmit information instantanously
Let me address this - perhaps your main point - in a little more detail:
Note that Maxwell's first equation (Jackson 6.28) is a
differential equation which concerns values only _at one point_:
"divergence of vector field D at coordinates r and t
= 4 Pi charge density at coordinates r and t"
This equation by itself doesn't involve any "transmission".
If there's no charge (density) at given coordinates r, then divergence
of vector field D is defined and remains equal to zero, no matter what
else might be going on at other coordinates.
One can consider the integrated equation, since this involves different
coordinates which might allow to comtemplate some sort of "transmission"
between them at all. Using Gauss' theorem, the statement then is:
"vector field D integrated over a closed surface (noting direction)
= 4 Pi the charge contained within that surface"
There are two ways of changing the content of a closed surface,
in the attempt to somehow "affect the entire surface, perhaps at once":
Either content simply appears or vanishes without crossing the boundary -
but such content is not "charge", by definition; as discussed earlier.
Or the content moves through the boundary, as a current -
that's described as time dependence in the remaining Maxwell equations
and by the resulting wave equations.
bilge
>
>And this first Maxwell equation entails that it is possible to
>transmit information instantanously. The change in charge of
As normally written, what else would you expect? It's written from
the point of view of an observer in a particular frame of reference
without the benefit of being relativistically correct: the frame
containing the charge. To show an inconsistency, you'd need clear
experimental evidence that properly transforming the events gave the
wrong result. This should be easy simply by moving past at some
velocity. relativity predicts a B-field in addition to the E-field.
If you take maxwell's 4 equations and transform them into 2
relativistically correct ones, I believe this problem goes away.
F^{\mu \nu}, not E & B separately is the correct quantity to explore.
You'll have a hard time getting E & B correct everywhere if the
E-field changes instantly for any observer and the B-field depends
upon the relative velocity. You cant create charge to verify this
(except where the net is 0 and the charges appear at the same point,
so any effect from that cant help you).
>way, the induction effect is an instantanous effect. If this
>effect is used to transmit information over a distance of 3 m
>no time delay of 10 nanoseconds is predicted by the most
>obvious interpretation of Maxwell's equations.
>
Then it would serve as an excellent way to check. Especially since c
should really be associated with the propagation of information and
light received the honor by the grace of a massless photon and being
the only means of transmitting information. It did not have to be so.
Light could have consisted of photons with very small masses, leaving
the rate at which information is constrained to travel still at c,
photons a bit slower, a much harder time undertanding nature, and as
of the present, without a means of transmitting information at c.
The speed at which light travels isnt the constraint - it's the
ability for two observers to reconcile events using a description
that has the same form in both of their rest frames. Light just
happens to propagate at the same rate as information.
>inside a closed surface can always be determined by its effect
>on the surface. The movements of charges affect distant surfaces
It doesnt state that. You added the word "always" to mean "right now
in every frame of reference". Maxwell's eqns. predate such concepts.
You cant expect them to be infallible when it comes to describing
phenomena that wasnt known in terms of concepts that werent known.
>instantanously, otherwise the first Maxwell equation would be
>valid only in static situations and could not be used to derive
>e.m. radiation.
>
That's not true. A complete explanation of radiation from charges
lies outside of classical e-m, with or without considering relativity.
An ad hoc term, appended to maxwells eqns. that produces a result
that is approximately correct and has theoretical merit is a bonus,
not a liability. Since maxwell's eqns do not address the origin of
the radiation, you might expect some inconsistencies. However,
the inconsistency is in maxwell's eqn. It's ridiculous to try and
assert the equations are infallible and that a consistency argument
which uses as evidence, phenomena which relativity doesnt claim to
fully explain, invalidates sr. Radiation requires accelerated charges.
Acceleration is not feature built explicitly into either maxwell's
eqn. nor sr.
>In any case, Jackson's section on "scalar potential instantanous
>propagation" shows that instantanous e.m. effects not only have
>to be explained away on the experimental side but also on the
>theoretical side.
>
Sure. But they are related to localized effects that arent a part of
the theory. When you start asking about how the reaction of the
charge affects the radiation it emits, you're going to have a hard
time explaining things. The large scale effects of instantaneous
propagation that are testable should be evident if true. So far,
I've seen exactly one candidate that could potentially pose an
interesting problem for relativity and that's the "teleportation"
that quantum mechanics apparently permits, but it would only show
where sr was limited, not that it was totally invalid.
z@z
| Wolfgang G. wrote:
| > And this first Maxwell equation entails that it is possible to
| > transmit information instantanously. The change in charge of
| > a body affects its neighbourhood instantanously.
|
| Not true. You cannot create or destroy charge, because the
| electromagnetic current is conserved (div J = 0) -- that's a direct
| consequence of Maxwell's equations.
It is possible to change the charge of a body without creating or
destroying charge. So your remark is not relevant.
The question is whether the effect of the displacement of charged
particles propagates at c or instantanously.
| > In the same
| > way, the induction effect is an instantanous effect.
|
| Ditto.
Ditto.
Gruss, Wolfgang
Relationality versus Relativity:
http://members.lol.li/twostone/E/physics1.html
Harry H Conover
: Tom Roberts wrote:
: | Wolfgang G. wrote:
:
: | > And this first Maxwell equation entails that it is possible to
: | > transmit information instantanously. The change in charge of
: | > a body affects its neighbourhood instantanously.
: |
: | Not true. You cannot create or destroy charge, because the
: | electromagnetic current is conserved (div J = 0) -- that's a direct
: | consequence of Maxwell's equations.
:
: It is possible to change the charge of a body without creating or
: destroying charge. So your remark is not relevant.
Sure it is, otherewise to change the charge of a body requires the
passage of an electric current to supply or remove charge.
: The question is whether the effect of the displacement of charged
: particles propagates at c or instantanously.
Standing waves, the design of certain types of microwave
devices (magnetrons, klystrons, and planar triodes) along
with the design principles employed successfully on antennas all make
it very clear that the propagation rate is c (actually c modified by the
propagation factor of the dielectric medium).
Harry C.
Frank Wappler
> Frank Wappler [asked]:
> > How would you determine the coordinates of emission and reception
> > of some particular photon, wrt. each other?
> I suppose it depends upon the circumstances.
You're using not one, but different measurement procedures
to determine coordinate relations??
How would you then determine and characterize various "circumstances"
in order to select the corresponding measurement procedure to begin with?,
if not already through measured coordinate relations.
> a radioactive decay for example which emits a gamma and beta: [...]
> I know where the radioactive material is located, I can see
> the beta decay occur
My question was how you'd _determine "location"_ in the first place,
given what you see (of various charges, in various trials) ...
> I can detect a gamma with a detector
... or given what other detectors/observers see, in those trials.
> I suggested a density matrix. It contains all the information
> there is to know for a given situation.
And I asked already:
> > How is [the] density matrix [...] obtained in the first place?,
for a given situation;
and what exactly is "given" in any one trial, e.g. in the _next_ trial?
> > What "it" do you suggest is "destroyed in the process of observation"?
> > AFAIK, the exchange of a photon is only _established_ in the first place
> > by the receiver observing the transition between states of the emitter.
> I dont undertand your statement. Consider a transition that
> emits a photon, A->B + gamma.
It's not very helpful just to invent new names like "emitted photon"
or "+ gamma" in place of the presumed "it".
However, I can consider a transition "A->B" between two states
of the ordered set of one particular observer (or observer system) ...
> In the process, the photon gets absorbed by something along the way.
... and I can even consider someone observing this transition in turn, e.g.
"You_before_observing_A->B -> You_after_observing_A->B", or
"r_before_observing_A->B -> s_after_observing_A->B",
i.e. perhaps more concisely: (A->B ~ r->s);
and such a relation constitutes "exchange of a photon", AFAIK.
I can even consider "self observation":
either (simply, evidently):
"A_before_observing_A->B -> B_after_observing_A->B", i.e. (A->B ~ A->B),
or (more involved):
"B_before_observing_A->B -> C_after_observing_A->B", i.e. (A->B ~ B->C).
> If I observe it, certainly no one else will.
This seems to describe specificly
(A->B ~ You_before_observing_A->B -> You_after_observing_A->B).
> I can only observe it if it creates some disturbance I can measure.
That makes sense - I wouldn't know either how to distinguish between
you collecting the observation that "A->B",
you undergoing the transition between two states of your ordered
set of states: "You_before_observing_A->B -> You_after_observing_A->B", or
you "measuring a (this particular) disturbance".
> The photon doesnt have an existence which depends upon B.
Interesting, given that you introduced B (with the notion of
"transition") above. Surely you're not trying to explain existance
and measurements of "photons" independent of "transition"?
The question is still how to measure and unambiguously characterize any
particular "it/photon/gamma", given mutual observations of transitions.
Specificly, how to measure _whether or not_ or to which extent
> [...] the momentum and energy at B are such that the photon at A
> is kinematically able to meet the condition q^2 = 0 [...]
in the first place.
> q^2 = 0, should be sufficient to describe a propagating photon.
Well - if so, then at least "a propagating photon" seems described
entirely as a _relation_ between A, B, etc. alone (though I'd still
like to know more specificly how that relation is evaluated);
and "it/photon/gamma" is not "some_thing_it_self". That was my point.
> the obvious question that someone is bound to ask from your choice
> of a single photon going from A to [r] as reality is
> "why doesnt it go from [r] to A".
Well, _that_ would be a _different_ exchange of a photon,
as observed by A and r.
(A->B ~ r->s) is _not_ necessarily the same as (r->s ~ A->B).
(Btw., QM incorporates this principle in general;
cf. Sakurai, Modern Quantum Mechanics, eq. 1.2.12.)
> I dont think you were really suggesting nature makes such distinctions.
Surely observers who _describe_ each other/nature do.
Regards, Frank W ~@) R
p.s.
> I'm really not trying to imply too much about the process beyond
> trying to emphasize any symmetry that, if absent, would suggest
> fundamentally different roles played by the emitter and absorber in
> the virtual case. The analogy shouldnt be taken too seriously as
> a literal occurence. I was more interested in making the symmetry
> explicit, not suggesting you can literally assume two photons do
> precisely as I suggested. That's one of those things you cant measure,
Then this doesn't seem relevant to the question I had asked in
Frank Wappler
> I've seen exactly one candidate that could potentially pose an
> interesting problem for relativity and that's the "teleportation"
> that quantum mechanics apparently permits
For "teleportation" to be a problem,
the determination of pairwise coordinate relations
("localization", "separation", "propagation", etc.)
would have to independent of the "teleportation" procedure
(and the procedure by which to assert what, if anything, has been
"teleported" at all).
However, in relativity
(i.e. when using Einstein's procedures for determining pairwise
coordinate relations, based on the exchange of light signals itself)
they are not independent;
therefore "teleportation" can't be a problem for relativity.
bilge
>More specificly, and quite independent of anyone's expectations,
>if different results have been obtained by merely facing a different
>direction and anisotropy is thereby indicated in those particular trials,
>for the region containing those trials,
>then Nöther's theorem would allow to conclude that angular momentum
>_was not_ conserved, in those particular trials, in the region containing
>those trials.
>
Why is that unexpected? What noether's theorem states and wrt
to angular momentum is:
(1) For every symmetry of the lagrangian,
or
(2) If I can perform any experiment and
rotate my apparatus through any angle
relative to the original experiment
and the result does not change, then
or
(3) A system which is spherically symmetric,
(1) there corresponds a conserved current
or
(2) angular momentum is a conserved quantity.
or
(3) has a total angular momenntum of zero.
>
>How and wrt. whom does one determine "direction" in the first place,
>and whether or to which extent any pair of experiments
>"face in different direction"?
>
Why does it matter how you choose it? It has to work
regardless of your choice. If it isnt true for some
choice, it's wrong.
>Sure; but I'd like to know how to _measure_ angular momentum,
>trial by trial, and thereby to determine whether or to which extent
>some particular system _is_ "closed" (wrt. angular mometum).
>
You cant ever be certain you are dealing with a closed system. The
neutrino would not have been predicted if they had placed more faith
in what they could see, than their belief that angular momentum is
always conserved. I've generally considered more of a philosophical
statement that all of the apparent complexity found in nature
may be explained by nothing but the very simplist symmetry argument.
It just isnt easy to guess which symmetry in every case. It works
quite well though so long as you dont talk about gravity too much.
>How and wrt. whom was angular momentum measured, in order for
>the comparison of resulting values (before and after the decay,
>I suppose) to be meaningful?
>
Take netron decay. the neutron is a spin 1/2. When it decays, what you
see is a proton and an electron. Both of those are also spin 1/2. J
can only add to 0 or 1 for two spin 1/2's. The only way to restore
conservation of angular momentum is to postulate a third spin 1/2
object (1) that you didnt see, (2) is very light, (3) is really an
anti-particle to also conserve lepton number, (4) is not charged so
you also conserve charge and so doesnt interact via the e-m
interaction.
Each one of those predictions comes from believing in a conservation
law more than an experiment. (However, this approach failed pretty
miserably when everyone assumed that parity was an "obvious" candidate
for conservation)
>How are the Dirac Hamiltonian, L and L+S to be measured, separately,
>to begin with?
>If you understand them as defined in terms of coordinate relations,
>"x_mu", and the derived operator "d/dx_mu()", etc.
>then how and wrt. whom are _those_ to be measured?
>
A magnetic field does it, in principle. To get the behaviour in the
low energy limit, one can perform (hpoefully better than I can spell)
a foldy-wouthuysen transformation and then in the words of many a
physics textbook, "after some algebra, it is readily seen that"
terms coupling S, L to an external field appear. (This would be
a miracle to do in ascii, so for a real treatment that considers no
detail too small to be left unexamined, see bjorken & drell Vol I.
>Also, if the Dirac Hamiltonian (and/or Lagrangean) happen to commute
>with L+S, then measurements of L+S may be useful for _counting_
>certain particles.
>
I'd have to think about that, unless you had something in
mind.
>Given the fact that particles don't seem to "spin" in the ordinary
>sense of the word, that suggestion may have sprung from
>convenience and opportunity, instead intuition ...
>
I may give those guys more credit than the facts would allow. I just
never cease to be astonished at how well dirac, feynman and the rest
of the bunch took a real mess and by insisting on simplicity, ended up
with qed.
>
>In which sense is a comparison with, say, the count in channel 598
>any less wrong than that, or a comparison with some other count
>obtained by channel 599?
>
It's wrong because by itself it doesnt mean anything. You need
a number of points with some relationship.
>If not at least counts/numbers can be unambiguously understood
>and reproduced by _anyone_, at least in principle, then ...
>what else should one try to communicate instead?
>
I may have made an unwarrented assunption that waht I meant was
obvious, when it probably isnt. Consider counting decay for a period
of 10 half-lives. Divide up the time into bins and you get the
standard decay curve. The fact that you have a count in some bin,
doesnt have enough information to combine with the results of
another expt, but a completed measurement does.
Frank Wappler
> What noether's theorem states and wrt to angular momentum is:
> (1) For every symmetry of the lagrangian,
> or
> (2) If I can perform any experiment and
> rotate my apparatus through any angle
> relative to the original experiment
> and the result does not change, then
> or
> (3) A system which is spherically symmetric,
> (1) there corresponds a conserved current
> or
> (2) angular momentum is a conserved quantity.
> or
As well an inverse, concerning any specific "asymmetry", I suppose.
> Why is that unexpected?
It _isn't_ unexpected, AFAIK, it's a mathematical theorem; and
> > quite independent of anyone's expectations.
Frank Wappler [wrote]:
> > How and wrt. whom does one determine "direction" in the first place,
> > and whether or to which extent any pair of experiments
> > "face in different direction"?
> Why does it matter how you choose it?
Because it seems that on this choice of the coordinate relations
between the individual experimental trials _depends_
whether a measurement about "angular momentum", or for instance
about "four momentum", or about any other particular quantity
is obtained from the set of results, through Nöther's theorem.
> It has to work regardless of your choice.
Sure it does; it's mathematics.
But how do you find out which particular (a)symmetries are involved
in some particular _measurement_?
> If it isnt true for some choice, it's wrong.
Do you suggest to evaluate _experimentally_ "whether it's true"?
How should measurements for such a determination be obtained
in the first place, independently of using Nöther's theorem?
> > How are the Dirac Hamiltonian, L and L+S to be measured, separately,
> > to begin with?
> [...] A magnetic field does it, in principle.
And how does one measure a "magnetic field" in the first place,
trial by trial; or at least "the most probable magnetic field"
over some set of trials?
> > Also, if the Dirac Hamiltonian (and/or Lagrangean) happen to commute
> > with L+S, then measurements of L+S may be useful for _counting_
> > certain particles.
> Take neutron decay. the neutron is a spin 1/2. When it decays,
> what you see is a proton and an electron. Both of those are also spin 1/2.
> J can only add to 0 or 1 for two spin 1/2's.
Indeed, the difference (before vs. after the dacay) seems to be manifest
quite independent of the specific "magnetic field" and "Hamiltonian",
in each decay (or inverse) trial.
That seems a particular efficient way to measure (some aspect of) L+S,
and thereby to see/count a third spin 1/2, per decay (or inverse).
> You need a number of points with some relationship.
> Consider counting decay for a period of 10 half-lives.
> Divide up the time into bins and you get the standard decay curve.
> The fact that you have a count in some bin, doesnt have enough
> information to combine with the results of another expt,
> but a completed measurement does.
Then what constitutes the relationship between
a count in one bin, and a count in some other bin in the first place?,
especially considering your statement:
> You cant ever be certain you are dealing with a closed system.
(Though the example above might indicate that we _can_ be certain of
dealing with closed systems, at least wrt. their contents of spin 1/2s,
since spin 1/2s are being counted on this assumption in the first place.)
Regards, Frank W ~@) R
p.s.
> I just never cease to be astonished at how well dirac, feynman
> and the rest of the bunch took a real mess and by insisting
> on simplicity, ended up with qed.
I just never cease to be astonished
how unambiguous scientific reproducibility
could be confused with plain simplicity.
bilge
>>
>I find these Popperian doctrines rather simplistic, overlooking the
>obvious as it were. You can produce theorems based on the principles of
>what is done in measurement.
>
So find a way to restate the theorem so that it fits
your criteria.
bilge
>
>and "it/photon/gamma" is not "some_thing_it_self". That was my point.
>
them not as things. I dont consider particles as "things" either.
The facy that the photon has no rest-frame makes the concept
of "when" and "where" sort of fuzzy, too.
>Then this doesn't seem relevant to the question I had asked in
>reply to Moataz H. Emam,
>
>Frank Wappler [wrote]:
>. By which measurement procedures are the extent of time, translation
>. and/or rotation symmetries determined experimentally in the first place?
Then somewhere I missed a (some) post(s). There seemed to be two
distinct topics here. If that wasnt the case, then I'm contributing
to confusion by pursuing this apparent tangent.
z@z
|>
|> Virtual photons can not only have mass, they can have the longitudinal
|> polarization states that result. There is only one difference between
|> a real photon and a virtual one: a real one satisfies q^2 = 0 and
|> may freely propagate.
Frank Wappler explains:
> Precisely; where q denotes the four-momentum that has been transferred
> between the two charges/observers who have exchanged this photon.
|bilge continues:
|> Photons carry momentum. The electrostatic
|> effect is the momentum carried by the photons due to the charge
|> of an object. The photons do not carry charge and so cannot change
|> any feature related to charge. All a photon can do is change the
|> momentum of another charged body upon absorption. Any charged body
|> may absorb a photon. If the absorber and emitter are different
|> bodies, the result looks like a force because the momentum change
|> in the emitter has to equal the momentum change in the absorber.
|> Virtual photons do not exist independent of the emitter. If a
|> charged object emits a photon, it must either re-absorb it to
|> satisfy heisenberg, or another charged object must absorb it to
|> satisfy heisenberg. Since the exchange could occur by swapping
|> the roles of emitter/absorber, it is symmetric and should be
|> interpereted that way. In that sense, an object absorbs the same
|> number of virtual photons it emits.
Tom Roberts comments:
|
|> [pretty good description of photon absorbtion/emission]
|
| Except for one "little" thing -- in a basis where individual photons
| have well-defined 4-momenta, the number operator does not have a well-
| defined value, and you cannot count them! In a basis where the number
| operator has a well-defined value, individual photons do not have
| well-defined 4-momenta! This is intimitely related to the fact that
| photons are indistinguishable Bosons, and to the necessity to
| symmetrize the wavefunction over Bosons and anti-symmetrize over
| Fermions -- in a perturbative approximation this intermixes all the
| Bosons/Fermions in all of the different diagrams....
|
| If one _really_ tries to take into account _all_ of the properties
| of photons in QED, the discussion gets so convoluted and complicated
| that it is essentially useless....
On the one hand we have the extremely simple and elegant
Coulomb law and on the other hand this obscure quasi-
mechanistic explanation of the same relation.
How can somebody taking seriously Ockham's razor prefer such
an obscure and logically inconsistent explanation to the
simple and elegant Coulomb law?
The QED explanation contains several concepts (elements)
which are at least as complex as the Coulomb law itself.
How can somebody taking seriously Ockham's razor explain
one simple concept by a combination of several complicated
concepts?
Virtual particles are assumed on the one hand to have
the needed properties (e.g. mass and momentum) and on
the other hand, if necessary, not to have the same
properties.
Actions at a distance are a far better explanation:
1) Photons as postulated by Einstein are real entities with
concrete values for mass, momentum and frequency. QED
'photons' only share the name with the original photons.
2) QED 'photons' would be logically refuted if Heisenberg had
not invented his famous uncertainty relations which allow
to circumvent necessary logical conclusions.
3) Electrostatic attraction cannot even be explained
qualitatively by 'QED' photons because under momentum
conservation two objects can only drift apart by exchanging
particles. (Perhaps the Heisenberg uncertainty relations
allow the assumption of negative mass and momentum :-)
4) In order to prevent isolated charged objects from radiating
more QED 'photons' than they absorb, one must assume that
the 'photons' are somehow tied to the objects. They fly away
at c and if they don't find another charge, they change
direction and fly back to the object. (It is certainly not
always easy for them to find back home :-)
5) Explaining interactions between charged objects by mediating
particles leads to the even more complex problem of how
these mediating particles interact with the charged objects.
6) Many experiments could be interpreted in a simpler and more
transparent way as confirmation of actions at a distance
than as confirmation of the currently accepted theories.
Wouldn't it be almost a miracle if such a strange and complex
behaviour as the one assumed for 'QED' photons resulted in
exactly the Coulomb law in all the many situations where this
law is experimentally confirmed?
Wolfgang Gottfried G.
Instantanous propagation of the 'electrostatic force':
http://www.deja.com/=dnc/getdoc.xp?AN=532021977
http://www.deja.com/=dnc/getdoc.xp?AN=532263367
http://www.deja.com/=dnc/getdoc.xp?AN=532665217
http://www.deja.com/=dnc/getdoc.xp?AN=533126325
http://www.deja.com/=dnc/getdoc.xp?AN=534705489
Aaron Bergman
>On the one hand we have the extremely simple and elegant
>Coulomb law and on the other hand this obscure quasi-
>mechanistic explanation of the same relation.
>
>How can somebody taking seriously Ockham's razor prefer such
>an obscure and logically inconsistent explanation to the
>simple and elegant Coulomb law?
>
>The QED explanation contains several concepts (elements)
>which are at least as complex as the Coulomb law itself.
But Coulomb's law doesn't fit experiment. It's not like we invent
these things just for our own amusement, after all.
>
>How can somebody taking seriously Ockham's razor explain
>one simple concept by a combination of several complicated
>concepts?
>
>Virtual particles are assumed on the one hand to have
>the needed properties (e.g. mass and momentum) and on
>the other hand, if necessary, not to have the same
>properties.
How many times does this have to be said? Virtual particles only
need to exist in a didactic sense. The full theory is a theory of
fields. You're attacking a caricature of the theory.
Aaron
--
Aaron Bergman
<http://www.princeton.edu/~abergman/>
Roy McCammon
> How can somebody taking seriously Ockham's razor prefer such
> an obscure and logically inconsistent explanation to the
> simple and elegant Coulomb law?
Ockham's razor only applies when two or
more explanations equally match the observations.
Opinions expressed herein are my own and may not represent those of my employer.
bilge
>Except for one "little" thing -- in a basis where individual photons
>have well-defined 4-momenta, the number operator does not have a well-
>defined value, and you cannot count them! In a basis where the number
>operator has a well-defined value, individual photons do not have
>well-defined 4-momenta! This is intimitely related to the fact that
>photons are indistinguishable Bosons, and to the necessity to
>symmetrize the wavefunction over Bosons and anti-symmetrize over
>Fermions -- in a perturbative approximation this intermixes all the
>Bosons/Fermions in all of the different diagrams....
>
>If one _really_ tries to take into account _all_ of the properties
>of photons in QED, the discussion gets so convoluted and complicated
>that it is essentially useless....
>
> There seems to be a Heisenberg uncertainty relationship
> between correctness and understandibility (:-)).
>
>
I'm going to have to sidestep the issue by asserting the the concepts
and physics cannot depend upon a particular representation and it's
not my intent to try and substitute the concept literally as a novel
computational scheme. I recognize the principle your principle is a
limitation on extending analogies, (but never in quite the excellent
and concise reperesentation you've chosen to coney it) :)
Frank Wappler
> Frank Wappler [wrote]:
> > [at least "a propagating photon" seems described entirely
> > as a _relation_ between A, B, etc. alone]
Therefore
> > "it/photon/gamma" is not "some_thing_it_self". That was my point.
> Unfortunately, the language doesnt make it easy
> to talk about them not as things.
Fortunately, language allows us to talk instead about
"the relations with each other of particles/charges, systems of those,
things, etc. who observe each other, at least in principle".
Most generally therefore: relations between observers;
as opposed to observers themselves.
> I dont consider particles as "things" either.
Really? Unfortunately, the language doesn't make it easy
to talk about them not as things.
Perhaps one could more precisely refer to particles as
"those who can determine coordinate relations wrt. each other,
at least in principle; and who can count, and be counted"?
> > [bilge/serling wrote:
> > > ... That's one of those things you cant measure]
> > Then this doesn't seem relevant to the question I had asked [...]
> Frank Wappler [wrote]:
> . By which measurement procedures [...]
Specificly: through which procedures should observers determine
and agree upon
> . the extent of time, translation and/or rotation symmetries
of the region in which they are contained, in any particular trial,
from their mutual observations collected in that trial.
Best regards, Frank W ~@) R
p.s.
> There seemed to be two distinct topics here.
(But there's only _one_ way to find out. :)
bilge
>As well an inverse, concerning any specific "asymmetry", I suppose.
>
Sure. something which allows you to distinguish two different
orientations isnt spherically symmetric.
>Because it seems that on this choice of the coordinate relations
>between the individual experimental trials _depends_
>whether a measurement about "angular momentum", or for instance
>about "four momentum", or about any other particular quantity
>is obtained from the set of results, through Nöther's theorem.
>
It comes down to your ability to determine a complete set of commuting
observables for a given situation. Unfortuantely, no theorem tells you
how to determine this and noethers theorem only tells you there are
conserved quantitiess to go with the ones you have. It doesn't tell
if you got it right. It only tells you when you get it wrong. The
degree to which you believe noether's theorem gives you confidence
to choose field theory and find the pieces missing in your observation
as opposed to the alternative, I guess is a matter of religion. I
personally, would be hard pressed to give up a few of the conservation
laws. I would consider giving up conservation of charge, for instance
a real problem.
>Sure it does; it's mathematics.
>But how do you find out which particular (a)symmetries are involved
>in some particular _measurement_?
>
THAT isnt always clear. The best you can do is to invoke some physical
intuition to identify the operator constructed from noether's theorm
with a physical measurement. I think anything obvious connecting a
particular symmetry to particular observables is obvious in retrospect.
No one thinks a whole lot the genius it took at the time to postulate
anti-particles to corresopnd to 2 degrees of freedom dirac probably
didnt want initially when trying to produce a relativistic wave eqn.
I dont think that most people would find it to be the obvious solution
without hindsight.
>Do you suggest to evaluate _experimentally_ "whether it's true"?
>How should measurements for such a determination be obtained
>in the first place, independently of using Nöther's theorem?
>
No. I'd just assume that it's true because it's the simplest ex-
planation that agrees with observation. If a real observation
somehow forces the conclusion that noether's theorem is unquestion-
ably at odds with mathematics, you have to go with observation and
look for the right description. I see no way to ever conclude
a description of nature is true beyond not having any evidence
refuting it and a belief based upon how well the theory works.
>And how does one measure a "magnetic field" in the first place,
>trial by trial; or at least "the most probable magnetic field"
>over some set of trials?
>
At the level you are talking about, I dont know. You might
look to the folks that spend their time measuring g-2 to
11+ decimal places for a state of the art answer. I also
suppose you can use something like a squid which is unmatched
for precision.
>Indeed, the difference (before vs. after the dacay) seems to be manifest
>quite independent of the specific "magnetic field" and "Hamiltonian",
>in each decay (or inverse) trial.
>That seems a particular efficient way to measure (some aspect of) L+S,
>and thereby to see/count a third spin 1/2, per decay (or inverse).
>
But it takes the implied belief in angular momentum conservation
to not dismiss it as an artifact of some new physics. Conservation
laws are emphasized so soon in physics that why they should be true
never gets asked or is met with incredulity. Usually, the connection
to symmetries (which for some reason seem more plausible than an ad hoc
assertion of a conservation law), doesnt happen until one is
introduced to field theory. I never cease to be amazed at where I can
employ symmetry arguments to simplify something.
>Then what constitutes the relationship between
>a count in one bin, and a count in some other bin in the first place?,
>
>especially considering your statement:
>
>> You cant ever be certain you are dealing with a closed system.
Only your belief that nothing has changed between counts. It's
just more plausible when you set something up that doesnt change
anything you can control. Also, the system isn't closed, nor can
you be assured of creating a closed system. Any time you count
charged particles, you are stuck with the possibility of counting
a cosmic ray by mistake or letting a decay slip through some
discriminator threshold. Unfortunately, you're stuck inferring
what the error free version of an experiment would say.
>
>(Though the example above might indicate that we _can_ be certain of
>dealing with closed systems, at least wrt. their contents of spin 1/2s,
>since spin 1/2s are being counted on this assumption in the first place.)
>
You cant be certain without invoking some reasonableness criteria.
You dont get the association without some idea of what alternative
explanations are reasonable.
>I just never cease to be astonished
>how unambiguous scientific reproducibility
>could be confused with plain simplicity.
>
Somewhere along the line, people are happier if you can be
assured the individual pieces are logically consistent. It
would be discomforting if newtonian physics wasnt a limiting
case of relativity and qm.
bilge
>
>On the one hand we have the extremely simple and elegant
>Coulomb law and on the other hand this obscure quasi-
>mechanistic explanation of the same relation.
>
>How can somebody taking seriously Ockham's razor prefer such
>an obscure and logically inconsistent explanation to the
>simple and elegant Coulomb law?
>
For one thing, Coulombs law provides no mechanism that tells
you how a charge exerts a force on another charge. You have to
assert some new physics and the idea of a special force, due
to charges. qed reduces the problem to conservation of momentum.
Most people consider reducing new physics to old physics with
a nice physical picture a reduction in complexity. You dont
get to insist on a simple disguise for the old physics to
use, however.
>The QED explanation contains several concepts (elements)
>which are at least as complex as the Coulomb law itself.
>
But, you can eliminate all of those concepts if you want
to give up what you give up accepting coulombs law - an
explanation of the underlying mechanism. qed allows you
to use coulomb's law. qed seeks explanations beyond what
coulomb's law can tell you. You just have to accept new
physics without hope of a mechanism if you want coulomb's
law to be the end of the line. You wont build quantum
computer's though.
>How can somebody taking seriously Ockham's razor explain
>one simple concept by a combination of several complicated
>concepts?
>
Nature chooses the implementation. Physics attempts to reverse
engineer it by second guessing the design as a whole. The pieces
dont fit into a working model without qed. A pile of screws
is simple, but you cant build a watch from them.
>Virtual particles are assumed on the one hand to have
>the needed properties (e.g. mass and momentum) and on
>the other hand, if necessary, not to have the same
>properties.
>
The standard vocabulary doesnt really have the words to convey
those concepts. We're much bigger than any effect quantum mechanics
predicts differently than classical mechanics and much smaller than
any effects you need relativistic mechanics to explain. So, an
everyday description vocabulary to evoke a picturesque and correct
discription of virtual particles just hasnt been important in
developing a vocabulary. On the other hand, the existing vocabulary
reinforces concepts which you have to abandon to have any intuition
for relativity or qm. Like, "now", or "solid object".
>Actions at a distance are a far better explanation:
>
>1) Photons as postulated by Einstein are real entities with
> concrete values for mass, momentum and frequency. QED
> 'photons' only share the name with the original photons.
>
Even here, your "classical" photon fails and must be rescued
by concepts of field theory. A monochromatic plane wave is
the only photon with definite values for these things. Classically
the energy is infinite if the frequency is definite. So you
must construct a real photon by superposition. Where do they
originate to perform the classical construction? Quantum
mechanics rescues you here. A plane wave has an infinite
energy and it must fill all of space. They may exist, but if
they fill all of space, they arent observable and so may
be redefined into the vacuum. Observing any effect of a plane
wave isnt obsevable, but you arent precluded from summing an
infinite number of them to produce something that is.
>2) QED 'photons' would be logically refuted if Heisenberg had
> not invented his famous uncertainty relations which allow
> to circumvent necessary logical conclusions.
>
Sure. All of quantum mechanics and the semiconductors it made
possible rest on the uncertainty principle. The very existence
of stable matter rests upon the uncertainty principle.
>3) Electrostatic attraction cannot even be explained
> qualitatively by 'QED' photons because under momentum
> conservation two objects can only drift apart by exchanging
> particles. (Perhaps the Heisenberg uncertainty relations
> allow the assumption of negative mass and momentum :-)
>
No. Here is where heisenbergs uncertainty principle really
earns its reputation. The location of the exchanged photon
is uncertain to the extent allowed by the uncertainty principle
for any given uncertainty in the momentum. Nothing precludes
the photon from having a momentum in the opposite direction
than you would expect classically from its position. It may
then, for example, be in the vicinity of a particle to the left
of the one that emitted it AND have a momentum which points
to the right, TOWORD the particle that emitted it.
>4) In order to prevent isolated charged objects from radiating
> more QED 'photons' than they absorb, one must assume that
> the 'photons' are somehow tied to the objects. They fly away
> at c and if they don't find another charge, they change
> direction and fly back to the object. (It is certainly not
> always easy for them to find back home :-)
>
No. By the same argument as above, it's location may be anywhere
that the uncertainty principle allows. The uncertainty principle
allows it to live no longer than the uncertainty in energy permits.
The photon's position always has a probability of being right where
it started, so when it's time is up, no inconsistency results
because it's always where it needs to be.
>5) Explaining interactions between charged objects by mediating
> particles leads to the even more complex problem of how
> these mediating particles interact with the charged objects.
>
You cant win them all. Unfortunately, having to figure this out
doesnt go away classically, either. Because only the fields matter
and not the potentials, you are allowed a choice of gauge to
simplify your life for any particular problem. The gauge freedom
forces you to have photons.
>6) Many experiments could be interpreted in a simpler and more
> transparent way as confirmation of actions at a distance
> than as confirmation of the currently accepted theories.
>
Only if you wish to skip understanding the mechanism. Trying
to recast an explanation of the electron magnetic moment
into ad hoc terms appended to maxwell's eqns would be worse
than hideous and more opaque than a political speech.
>Wouldn't it be almost a miracle if such a strange and complex
>behaviour as the one assumed for 'QED' photons resulted in
>exactly the Coulomb law in all the many situations where this
>law is experimentally confirmed?
>
It does, its wonderful, but not a miracle or particularly strange.
It would be strange if it didnt and anyone considered it wonderful
enough to call a miracle.
Charles Francis
It is done
http://xxx.lanl.gov/abs/physics/9905058
A Theory of Quantum Space-time
--
Charles Francis
cha...@clef.demon.co.uk
z@z
| > Virtual particles are assumed on the one hand to have
| > the needed properties (e.g. mass and momentum) and on
| > the other hand, if necessary, not to have the same
| > properties.
|
| How many times does this have to be said? Virtual particles only
| need to exist in a didactic sense. The full theory is a theory of
| fields. You're attacking a caricature of the theory.
Since when do didactic particles carry momentum? :-(
Huge forces of electostatic repulsion and attraction do occur
in nature. QED explains these forces by assuming QED 'photons'
carrying momentum, isn't it? If you tried to create the same
forces using real photons, you would recognize how many high
energy photons would be necessary for that. But the higher
the energy of photons, the less relevant are Heisenberg's
uncertainty relations. So we must assume that huge (but
uncertain) numbers of low energy 'photons' must be involved.
It makes no sense to reduce electrostatic forces superficially
to 'photons' and conservation of momentum, if conservation of
momentum in principle can only lead to the opposite of what is
observed in the case of attraction. I think it is better to
explain a force by an action at a distance than by a local
action which according to correct logical reasoning could only
lead to a force in the opposite direction.
Feynman or who else is responsible for this strange idea may
have overlooked the fact that not all mechanical situations are
time reversible:
Two ships can drift apart if the passengers throw objects from
one ship to the other. The opposite however, is not possible.
Aaron Bergman
>Hello Aaron Bergman!
>
>| > Virtual particles are assumed on the one hand to have
>| > the needed properties (e.g. mass and momentum) and on
>| > the other hand, if necessary, not to have the same
>| > properties.
>|
>| How many times does this have to be said? Virtual particles only
>| need to exist in a didactic sense. The full theory is a theory of
>| fields. You're attacking a caricature of the theory.
>
>Since when do didactic particles carry momentum? :-(
>
>Huge forces of electostatic repulsion and attraction do occur
>in nature. QED explains these forces by assuming QED 'photons'
>carrying momentum, isn't it?
QED explains this by the interaction of various fields. In the
first order, this can be approximated by something that looks
like the expression for the exchange of a particle. This
"particle" doesn't obey all the same rules as a normal particle,
so it's called a virtual particle. But, it's only an
interpretation of an approximation.
Tom Roberts
> How can somebody taking seriously Ockham's razor prefer such
> an obscure and logically inconsistent explanation to the
> simple and elegant Coulomb law?
Because QED explains many more phenomena to far better accuracy than
does Coulomb's law.
> 1) Photons as postulated by Einstein are real entities with
> concrete values for mass, momentum and frequency. QED
> 'photons' only share the name with the original photons.
And the problem with this is?
> 2) QED 'photons' would be logically refuted if Heisenberg had
> not invented his famous uncertainty relations which allow
> to circumvent necessary logical conclusions.
Nonsense. You just do not understand QED, that's all. For a simple
and entertaining introduction:
Feynman, _QED_.
> 3) Electrostatic attraction cannot even be explained
> qualitatively by 'QED' photons because under momentum
> conservation two objects can only drift apart by exchanging
> particles. (Perhaps the Heisenberg uncertainty relations
> allow the assumption of negative mass and momentum :-)
You _really_ do not understand QED or how virtual particles work.
Attraction is easily explained -- the virtual photons are off the
mass shell, and their _interference_ causes net momentum transfer.
> 4) In order to prevent isolated charged objects from radiating
> more QED 'photons' than they absorb, one must assume that
> the 'photons' are somehow tied to the objects.
You _really_ do not understand QED. One cannot "count" photons
except in exceptional circumstances. But no matter -- energy and
momentum are conserved, at each vertex, for each diagram, and
overall for the entire summation of diagrams.
This is, of course, in a perturbative approximation to QED.
That's really the only context in which photons arise.
> 5) Explaining interactions between charged objects by mediating
> particles leads to the even more complex problem of how
> these mediating particles interact with the charged objects.
You _really_ do not understand QED. Actually, the vertex functions
in QED are quite simple.
> 6) Many experiments could be interpreted in a simpler and more
> transparent way as confirmation of actions at a distance
> than as confirmation of the currently accepted theories.
Try accounting for the gyromagnetic ratio of the electron. QED agrees
with experiment to 11 significant digits.
> Wouldn't it be almost a miracle if such a strange and complex
> behaviour as the one assumed for 'QED' photons resulted in
> exactly the Coulomb law in all the many situations where this
> law is experimentally confirmed?
As Arthur C. Clarke said, "Sufficiently advanced technology is
indistinguishable from magic."
Here the "advanced technology" is the simple fact that in the
appropriate limit QED is accurately approximated by Maxwell's
equations, including Coulomb's law. But Maxwell's equations cannot
explain the gyromagnetic ratio of the electron....
Tom Roberts tjro...@lucent.com
Jim Carr
"z@z" <z...@z.lol.li> writes:
>
>Frank Wappler, thank you very much for the translated quotes.
>
>These quotes show that HEINRICH HERTZ has indeed found in his
>experiments that ELECTROSTATIC effects propagate INSTANTANOUSLY
>and NOT at c as generally assumed.
Where do you think that it is assumed anywhere that *static*
(unchanging in time) fields have to propagate (travel) at all?
Certainly not in the theory of Maxwell that Hertz was testing.
Note followups.
--
James A. Carr <j...@scri.fsu.edu> | Commercial e-mail is _NOT_
http://www.scri.fsu.edu/~jac/ | desired to this or any address
Supercomputer Computations Res. Inst. | that resolves to my account
Florida State, Tallahassee FL 32306 | for any reason at any time.
Frank Wappler
> noethers theorem only tells you there are conserved quantities
> to go with the ones you have. It doesn't tell if you got it right.
> It only tells you when you get it wrong.
Based on what does this mathematical theorem "tell me" that?
How are symmetries (in coordinate relations) and/or (equivalently)
currents (such as angular momentum, or four momentum)
to be _measured_ in the first place?
> Frank Wappler [wrote:]
> > But how do you find out which particular (a)symmetries are involved
> > in some particular _measurement_?
> The best you can do is to invoke some physical intuition [...]
Which particular intuition do you invoke when trying to measure
the value of a pairwise distance, "x", in some experimental trial?
Einstein's calibration procedure, and the associated distance definition?
Or what else, and why?
Which particular intuition do you invoke when trying to measure
the value of "angle, phi"?
> > Do you suggest to evaluate _experimentally_ "whether it's true"?
> > How should measurements for such a determination be obtained
> > in the first place, independently of using Nöther's theorem?
> No. I'd just assume that it's true because it's the simplest ex-
> planation that agrees with observation.
How were measurements being derived from those observations,
independently of using Nöther's theorem?
> > And how does one measure a "magnetic field" in the first place,
> > trial by trial; or at least "the most probable magnetic field"
> > over some set of trials?
> At the level you are talking about, I dont know. You might
> look to the folks that spend their time measuring g-2 to
> 11+ decimal places for a state of the art answer.
Some of those folks seem to use certain set-ups consisting
of charges with a priori unknown g-2 value, in order to
determine the g-2 value of a given charge.
(I wouldn't necessarily call it "to measure".
At the level you know, you might wonder about that, too.)
> I also suppose you can use something like a squid which
> is unmatched for precision.
But how and wrt. what else would one determine _accuracy_
of any particular squid, in any particular trial?
> > (Though the example above might indicate that we _can_ be certain of
> > dealing with closed systems, at least wrt. their contents of spin 1/2s,
> > since spin 1/2s are being counted on this assumption in the first place.)
> You cant be certain without invoking some reasonableness criteria.
> You dont get the association without some idea of what alternative
> explanations are reasonable.
No: there is no reasonable alternative to
1/2 = 1/2 + 1/2 - 1/2, 1/2 =/= 1/2 - 1/2, and 1/2 =/= 1/2 + 1/2;
only variations in notation.
> > That seems a particular efficient way to measure (some aspect of) L+S,
> > and thereby to see/count a third spin 1/2, per decay (or inverse).
> But it takes the implied belief in angular momentum conservation
> to not dismiss [neutrinos] as an artifact of some new physics.
Since this "belief" apparently is based only on counting,
and allows to count in turn, it seems as unambiguous and reproducible
as one requires for a "procedure".
Could you suggest any essentially different procedure by which
to search for "artifacts of some new physics" anyways?
Of course, with the "neutrino" having been assigned already,
the particular efficient way from above seems already used up ...
> > What constitutes the relationship between
> > a count in one bin, and a count in some other bin in the first place?,
> Only your belief that nothing has changed between counts.
At least the counts themselves might have changed though,
between trials. If so, ought those trials be discarded?
> It's just more plausible when you set something up
> that [it?] doesnt change anything you can control.
Of course, requiring "plausibility" might conflict with search for
"artifacts of some new physics"; unless perhaps "plausibility"
is meant synonymous with "what anyone can count".
But OTOH, the (if any) relation between various counts was sought
in the first place ...
And what exactly can I control, in any particular trial? -
Well, at least perhaps my individual observations and judgement
on whether or not that trial was "sufficiently same" as others
wrt. which I'd like to compare/measure the result.
> Unfortunately, you're stuck inferring what the error free version
> of an experiment would say.
I suppose that in general one can only infer the "most probable"
contributions of various interfering "signal sources".
But at least a "count" is based on the observation of one ("counter"),
not a more complicated pariwise relation such as "distance", or "angle".
> > I just never cease to be astonished
> > how unambiguous scientific reproducibility
> > could be confused with plain simplicity.
> It would be discomforting if newtonian physics wasnt a limiting
> case of relativity and qm.
What's newtonian "physics"? Did Newton suggest any measurement
procedures, for instance about how to determine values of "x"?
Best regards, Frank W ~@) R
p.s.
> I never cease to be amazed at where I can employ symmetry arguments
> to simplify something.
I never cease to be amazed at how little difference there is
between "simplifying something" and "employing symmetry arguments".
bilge
>
>Since when do didactic particles carry momentum? :-(
>
>Huge forces of electostatic repulsion and attraction do occur
>in nature. QED explains these forces by assuming QED 'photons'
may ask certain questions regarding the importance of some
finite part of the process, but you cant talk about "a
photon" except as an physically appealing representation of
a term in a series. If you allow virtual photons to differ
from real ones to begin with, why is it such a problem to
include other self-consistent properties to motivate the
physics that are not properties of a real photon?
>forces using real photons, you would recognize how many high
>energy photons would be necessary for that. But the higher
>the energy of photons, the less relevant are Heisenberg's
>uncertainty relations. So we must assume that huge (but
>uncertain) numbers of low energy 'photons' must be involved.
>
of a single photon represents only the lowest order approximation.
As you scatter two charges at higher and higher energies, higher
order terms become more important to include. Look up vacuum
polarization and compare it with the classical point charge in
a dielectric.
>observed in the case of attraction. I think it is better to
>explain a force by an action at a distance than by a local
>action which according to correct logical reasoning could only
>lead to a force in the opposite direction.
>
the process altogether, provided you never need to go beyond
any limitations such an explanation builds in. qed has to
reduce to classical e-m in the appropriate limit, or it would
never have gained acceptance.
>Feynman or who else is responsible for this strange idea may
>have overlooked the fact that not all mechanical situations are
>time reversible:
>
>Two ships can drift apart if the passengers throw objects from
>one ship to the other. The opposite however, is not possible.
>
It's not a quantum process. You just cant throw a virtual rock.
You also cant create a magnetic field by running, but the fact that
you dont carry an intrinsic charge doesnt prevent you from believing
in the concept of a charge does it? Just to make the situation worse
here, try to figure out what a charge really is if you think you need
to place such conceptual restraints on how qed uses photons. I'll
bet you've always just taken it as a given "thing". Why should
accepting something like virtual photons which are no less weird
than a charges be particulary objectionable? Consider the possibility
that your everyday experiences just dont apply in the world of the
very small. The fact that you are too large to personally experience
\hbar sized events, means your concept of how things should work is
biased. The scales of events where either \hbar or c become important
are very different than the scale of events we experience personally.
It shouldnt be to surprising to find some things at those scales to
be at odds with everyday experience.
--
Cancelled posts are just like
regular posts; they just arent on
mass shell.
Charles Francis
<aber...@princeton.edu> writes
>>Huge forces of electostatic repulsion and attraction do occur
>>in nature. QED explains these forces by assuming QED 'photons'
>>carrying momentum, isn't it?
>
>first order, this can be approximated by something that looks
>like the expression for the exchange of a particle. This
>"particle" doesn't obey all the same rules as a normal particle,
>so it's called a virtual particle. But, it's only an
>interpretation of an approximation.
QED is better understood as an exact theory of particle interactions in
pre-geometric space, than an approximate theory of fields.
http://xxx.lanl.gov/abs/physics/9905058
A Theory of Quantum Space-time
http://xxx.lanl.gov/abs/physics/9909051
A Pre-Geometric Model Exhibiting Physical Law
--
Charles Francis
cha...@clef.demon.co.uk
Charles Francis
> >uncertain) numbers of low energy 'photons' must be involved.
> >
>
> There are precisely an infinite number involved.
Precisely infinite, or finite but indefinite? Infinite just means a
finite number larger than the number you first thought of. The number of
photons is finite, but whatever number you think of, there is a
possibility that there may be more. Only changes in the number of
photons actually have a physical effect, so the actual number is
completely unknown, and partly explains gauge invariance.
>
> >Feynman or who else is responsible for this strange idea may
> >have overlooked the fact that not all mechanical situations are
> >time reversible:
> >
Only on the basis that time symmetry is broken by statistical laws.
--
Charles Francis
cha...@clef.demon.co.uk
bilge
>Based on what does this mathematical theorem "tell me" that?
>How are symmetries (in coordinate relations) and/or (equivalently)
>currents (such as angular momentum, or four momentum)
>to be _measured_ in the first place?
>
I'm conviced this is either a put on or redefines what it means to
be pedantic. After getting toward the end, I decided you really
werent interested in an answer. so I removed what would have been
another way to say the same thing again and said something different
but just as useful.
>
>Which particular intuition do you invoke when trying to measure
>the value of a pairwise distance, "x", in some experimental trial?
>Einstein's calibration procedure, and the associated distance definition?
>Or what else, and why?
>
The fact you're ruler isnt bent.
>Which particular intuition do you invoke when trying to measure
>the value of "angle, phi"?
>
Hold your arms up in a vee, but call it phi.
>
>How were measurements being derived from those observations,
>independently of using Nöther's theorem?
>
Because noether's thm. isnt an observable. It doesnt
conserve paper.
>Some of those folks seem to use certain set-ups consisting
>of charges with a priori unknown g-2 value, in order to
>determine the g-2 value of a given charge.
>
>(I wouldn't necessarily call it "to measure".
>At the level you know, you might wonder about that, too.)
Check for the NIS certification on the electron's arrow.
>But how and wrt. what else would one determine _accuracy_
>of any particular squid, in any particular trial?
>
1 decimal place per tentacle.
>No: there is no reasonable alternative to
>
>1/2 = 1/2 + 1/2 - 1/2, 1/2 =/= 1/2 - 1/2, and 1/2 =/= 1/2 + 1/2;
>
>only variations in notation.
>
So you found the minimum through a variation of the
plausible action? Is it implausible at the endpoints?
>Since this "belief" apparently is based only on counting,
>and allows to count in turn, it seems as unambiguous and reproducible
>as one requires for a "procedure".
>
You need enough fingers to hold all the counts.
>Could you suggest any essentially different procedure by which
>to search for "artifacts of some new physics" anyways?
>Of course, with the "neutrino" having been assigned already,
>the particular efficient way from above seems already used up ...
>
Dont find the axion. Since it's supposed to exist, you
can unexplain strong cp-violation by not finding it.
>
>At least the counts themselves might have changed though,
>between trials. If so, ought those trials be discarded?
>
Is this question for real? I cant believe you actually have to
have this conversation everytime you pick up a ruler.
>Of course, requiring "plausibility" might conflict with search for
>"artifacts of some new physics"; unless perhaps "plausibility"
>is meant synonymous with "what anyone can count".
>But OTOH, the (if any) relation between various counts was sought
>in the first place ...
>
No. It's synonymous with plausible.
>And what exactly can I control, in any particular trial? -
Nothing. It's existential physics.
>Well, at least perhaps my individual observations and judgement
>on whether or not that trial was "sufficiently same" as others
>wrt. which I'd like to compare/measure the result.
>
ok.
>What's newtonian "physics"? Did Newton suggest any measurement
>procedures, for instance about how to determine values of "x"?
He asked Descartes.
Robert J. Kolker
Charles Francis wrote:
>
> Precisely infinite, or finite but indefinite? Infinite just means a
> finite number larger than the number you first thought of.
Nonsense. A set has infinite cardinality if it can be put into
a one to one onto mapping of itself into a proper subset of
itself.
Bob Kolker
Charles Francis
<bobk...@usa.net> writes
Mathematics has several definitions of infinity. I was using the
definition in analysis, which is the most practical and the most useful.
The definition, or rather axiom, of set theory to which you refer is
fine in so far as mathematics is only concerned with consistent systems
of thought, but cannot be applied to any physical situation.
--
Charles Francis
cha...@clef.demon.co.uk
Roy McCammon
> Based on what does this mathematical theorem "tell me" that?
> How are symmetries (in coordinate relations) and/or (equivalently)
> currents (such as angular momentum, or four momentum)
> to be _measured_ in the first place?
Pick up a rock. Face West. Drop the rock. Measure how long
it takes to hit the ground. Repeat many times. Average.
Now face North. Do it again.
Now face NE. Do it again.
Face many different directions and repeat.
If your averages agree to within your experimental
error, you may tentatively conclude that the direction
you face does not change your experimental outcome.
This experimental outcome is consistent with rotational symmetry.
Now do the experiment, but instead of changing directions,
take a step to the North and repeat. Do this for steps
in many directions. If your results agree to within
experimental error, your experimental outcome is consistent with
transitional symmetry.
Do it again. Only this time do it at different heights.
This time you find that the results are not the same
to within experimental accuracy. This is experimental
outcome is not consistent with transitional symmetry.
Frank Wappler
> Frank Wappler [wrote]:
> > the value of a pairwise distance, "x", in some experimental trial?
> The fact [that your] ruler isnt bent.
What do you mean by "a ruler being bent, or not bent"?
Do you require reference to pairwise distances, "x", or (perhaps
equivalently) to "rulers that aren't bent" already, in order to
establish this "fact" (your observation/assertion/intuition) as
a reproducible/meaningful/unambiguous, statement,
i.e. as a measurement, in the first place?
> > [...] there is no reasonable alternative to
> > 1/2 = 1/2 + 1/2 - 1/2, 1/2 =/= 1/2 - 1/2, and 1/2 =/= 1/2 + 1/2;
> > only variations in notation.
> So you found the minimum through a variation of the
> plausible action?
I can't quite follow how your qestions relates to my statement
(could you sketch this in a little more detail, please),
but yes: at least in principle, I can find stationary values
of "potential", i.e. I can find "the most probable potential",
from given measured coordinate relations as constraints;
I find it plausible to express "action" as a sum of
the expression for "potential", and the (operator?) expression C
which corresponds to the measurement procedure by which the
coordinate constraints have been determined,
times a Lagrangean multiplier;
and I find it plausible to express "potential V" for given C
through an estimate based on the Robertson-Schrödinger relations:
(Cp~Cp) (Cm~Cm) >= 1/4 (((Cm~Cp) - (Cp~Cm))~((Cm~Cp) - (Cp~Cm))) == V,
where Cp denotes the potential coordinate relations,
and Cm those which were measured.
> Is it implausible at the endpoints?
Dunno; that may depend on the specific measurement procedure
by which the coordinate relations are being obtained,
and hence on the corresponding (operator?) expression C.
Moataz H. Emam seemed to suggest (earlier in this thread)
that there were plausible measurement procedures for
determining time, translation and/or rotation symmetries.
Perhaps he can answer your question more specificly;
this was my question, too.
> > Could you suggest any essentially different procedure by which
> > to search for "artifacts of some new physics" anyways?
> > Of course, with the "neutrino" having been assigned already,
> > the particular efficient way from above seems already used up ...
> Dont find the axion.
How would you measure whether you've "found the axion", or not?
Also, whichever "things" you may attempt to find and to identify
based on their relations with each other, aren't they at least
_singly connected_ with each other, and hence spin 1/2?
(You know Dirac's - or was it Feynman's? - survivalist trick:
How to hold a bowl with _any_ sort of stew and to examine it
from all sides before eating, without turning food back
in the process already; and with one palm glued to your back?)
> > [bilge/serling wrote:
> > > Frank Wappler wrote:
> > > > What constitutes the relationship between
> > > > a count in one bin, and a count in some other bin
> > > > in the first place?,
> > > Only your belief that nothing has changed between counts.]
> > At least the counts themselves might have changed though,
> > between trials. If so, ought those trials be discarded?
> Is this question for real? I cant believe you actually have to
> have this conversation everytime you pick up a ruler.
Well, I might pick up a ruler (i.e. at least one of its ends)
in order to _determine_ its length, i.e. the distance of its
two ends wrt. each other, using for instance:
> > Einstein's calibration procedure, and the associated distance
> > definition
which don't require anyone's belief that "nothing has changed
between counts", but only that those who do the counting
remain identifiable throughout the measurement.
> > What's newtonian "physics"? Did Newton suggest any measurement
> > procedures, for instance about how to determine values of "x"?
> He asked Descartes.
Which measurement procedures did Descartes suggest?
Frank Wappler
> Frank Wappler wrote:
> > How are symmetries (in coordinate relations) and/or (equivalently)
> > currents (such as angular momentum, or four momentum)
> > to be _measured_ in the first place?
> Pick up a rock.
O.k. - let's assume that I can do that;
deciding reproducibly whether or not the distance
of some rock and myself wrt. each other has value zero.
(Now consider the trials in which it was zero, initially.)
> Face West.
But how do I determine whether or not I'm "facing West",
as you prescribe? That's my initial question;
and it comes up again throughout your post.
> Drop the rock.
(i.e. discard all trials in which the distance of this rock and myself
wrt. each other remained zero throughout. Can do!)
> Measure how long it takes to hit the ground.
Well - I may observe (after having observed that I dropped the rock)
that this rock and the ground have found their distance wrt. each other
of value zero, too.
Perhaps I can even derive from those (and additional) observations
a _measurement_ about the "length" of this interval, between
me observing the rock dropping, and the ground observing the rock hitting.
> Repeat many times.
Fine - but with the caveat that I still don't know whether or
to which extent I've been "facing West" in each individual trial.
> Average.
So far, I have the ordered set of my observations, e.g.
{ ..., pickup_drop trial 1 rock, ..., pickup_drop trial 2 rock,
..., pickup_drop trial 3 rock, ..., trial 2 rock has hit ground,
..., pickup_drop trial 4 rock, ..., pickup_drop trial 5 rock,
..., trial 1 rock has hit ground, ..., trial 3 rock has hit ground, ... }
How should I "average" them?
> Now face North.
Again, how should I determine this, trial by trial?
Also, in case you gave a procedure to determine whether and to
which extent I'm "facing West" in any particular trial,
but if the procedure for determining whether and to which extent
I'm "facing North" were merely: "Face neither West, nor East",
then how should I determine whether and to which extent I'm
"facing North", "facing South", or "facing up" or "facing down",
in any one trial? Could there be any trials at all which satisfy
the prescription "Face neither West, nor East" at all?
(Of course here I'm just guessing - please specify how to "face North"!)
> Do it again. Face many different directions and repeat.
Fine, provided I _can distinguish_ various "different directions".
My initial question was how to do that in the first place, trial by trial.
> If your averages agree
So far I have only my ordered set of observations about
many individual trials; possibly distinguished by "direction".
Themselves they don't agree, of course - they are individually
distinct observations and trials.
Again: how should I obtain "averages", in order to compare them
and to evaluate whether and to which extent they agree?
(In order to be meaningfully comparable, "averages" should be
non-negative real numbers, I suppose.)
> to within your experimental error
How should I determine "my experimental error",
for my set of observed trials?
> you may tentatively conclude that the direction you face
> does not change your experimental outcome.
Why tentatively? - wouldn't there be obtained a _definite_ result,
for my set of observed trials?
Based on what would you perhaps "expect that most probably
the same result is obtained in the next trial"?
> This experimental outcome is consistent with rotational symmetry.
Alright, thanks a lot - that'll be very helpful if you could address
the remaining questions, please.
> Do it again.
... i.e. the entire procedure so far, IIUC ...
> Only this time do it at different heights.
How should I determine "height" (i.e. the distance of the ground
and myself wrt. each other) from my ordered set of observations
(those concerning the rock, and perhaps others, too)?,
trial by trial, such that I cound compare "heights"
and distinguish in which trials their values were different?
> This time you find that the results are not the same
> to within experimental accuracy.
Again: How and wrt. to what else should "experimental accuracy"
be determined in the first place, for my two sets of observed trials?
(provided I can distinguish them, by "height".)
> This [...] experimental outcome is not consistent
> with transitional symmetry.
This procedure seems to infer transitional symmetry from
different measurements of rotational symmetry;
unlike the measurement of rotational symmetry above itself
which followed from sets of measured "interval lengths" directly.
Are there procedures for determining transitional symmetry
just as directly?
Thanks again, Frank W ~@) R
Roy McCammon
> Well - I may observe (after having observed that I dropped the rock)
> that this rock and the ground have found their distance wrt. each other
> of value zero, too.
> Perhaps I can even derive from those (and additional) observations
> a _measurement_ about the "length" of this interval, between
> me observing the rock dropping, and the ground observing the rock hitting.
perhaps you could,
perhaps you could not.
bilge
>Precisely infinite, or finite but indefinite? Infinite just means a
>finite number larger than the number you first thought of. The number of
>photons is finite, but whatever number you think of, there is a
You are being pedantic. If you perform an explicit calculation and
identify photons with photon lines in the diagrams, you have an
infinite (countably, too) number of calculations to perform. The
electrons dont sit and calculate this and any inconsistency in
bookkeeping is from trying to approximate the interaction rather
than a real description. You can only talk about which diagrams are
important. At some point the exact semantics are important to obtaining
a mathematical answer, but it usually detracts from a physically
intuitive picture. Since every text I've seen feels free discuss
photons as single entities when convenient and to for physical appeal,
use "infinite" in ways that might make mathematicians shudder in a
mthematical context requiring rigor, I certainly dont feel compelled
to reconcile every physical description with a mathematically rigorous
one. I dont see that the doing so adds any appeal for the person that
wanted to know why qed was more appealing than using coulombs law,
since the lack of a physically intuitive process was a primary
objection.
bilge
>
>> So you found the minimum through a variation of the
>> plausible action?
>
>I can't quite follow how your qestions relates to my statement
>(could you sketch this in a little more detail, please),
>
/
\delta \ (P)dt = 0
/
>but yes: at least in principle, I can find stationary values
>of "potential", i.e. I can find "the most probable potential",
>from given measured coordinate relations as constraints;
>
>I find it plausible to express "action" as a sum of
>the expression for "potential", and the (operator?) expression C
>which corresponds to the measurement procedure by which the
>coordinate constraints have been determined,
>times a Lagrangean multiplier;
>
dplausible plausible
--------- - ----- = 0
dpedantic dpedantic DOT
>and I find it plausible to express "potential V" for given C
>through an estimate based on the Robertson-Schrödinger relations:
>
>(Cp~Cp) (Cm~Cm) >= 1/4 (((Cm~Cp) - (Cp~Cm))~((Cm~Cp) - (Cp~Cm))) == V,
>
Did Phys Rev Q¹ accept it? The first minus sign should be a stop sign.
1) The journal of questionable physics
>
>> Dont find the axion.
>
>How would you measure whether you've "found the axion", or not?
>
That's why I said dont find it. Finding it is much harder and
people expect it. If you dont find it, you can use a slot
machine for your experiment that failed to do so and predict
new physics too, while gambling with the grant money you
applied for to not find it.
>Also, whichever "things" you may attempt to find and to identify
>based on their relations with each other, aren't they at least
>_singly connected_ with each other, and hence spin 1/2?
>
Unless this isnt the case, of course.
>(You know Dirac's - or was it Feynman's? - survivalist trick:
>How to hold a bowl with _any_ sort of stew and to examine it
Did he measure the bowl?
>
>Which measurement procedures did Descartes suggest?
>
Mostly, one that works, though he made some good points
for ones that are questionable and at least one instance
where it might be advantageous to use a measurement technique
that consistently failed to be repeatable. It's been widely
implemented to produce data for marketing free energy.
Charles Francis
>
> >Precisely infinite, or finite but indefinite? Infinite just means a
> >finite number larger than the number you first thought of. The number of
> >photons is finite, but whatever number you think of, there is a
>
> You are being pedantic.
I accept the charge, but I would not be so pedantic if I did not think
that there are significant misconceptions wrapped up in the question of
the infinite. In this instance the question is of direct relevance to
gauge invariance, and in such a way that leads me to question the
relevance, or meaning, of so called "gauge theories".
>If you perform an explicit calculation and
> identify photons with photon lines in the diagrams, you have an
> infinite (countably, too) number of calculations to perform. The
> electrons dont sit and calculate this and any inconsistency in
> bookkeeping is from trying to approximate the interaction rather
> than a real description.
The diagrams do not individually state what happens in a given
interaction, but describe the possibilities of what may happen. There
are an infinite number of possibilities, but that is not the same as an
infinite number of photons.
>You can only talk about which diagrams are
> important. At some point the exact semantics are important to obtaining
> a mathematical answer, but it usually detracts from a physically
> intuitive picture. Since every text I've seen feels free discuss
> photons as single entities when convenient and to for physical appeal,
> use "infinite" in ways that might make mathematicians shudder in a
> mthematical context requiring rigor, I certainly dont feel compelled
> to reconcile every physical description with a mathematically rigorous
> one. I dont see that the doing so adds any appeal for the person that
> wanted to know why qed was more appealing than using coulombs law,
> since the lack of a physically intuitive process was a primary
> objection.
In this instance the question is of fundamental importance to the
interpretation of qed, and quantum mechanics in general. I believe that
is the main interest of the person wanting a non-rigorous description of
physical theory. To give such a person a non-rigorous description, and
be sure that it is right, someone has to work on the rigorous
description. At the moment it seems that academics and lecturers refuse
to acknowledge the need for such treatments in field theory. I regard
that as a matter of supreme incompetence, as well as professional
negligence in view of what the founders of the subject such as Dirac and
Feynman had to say on the subject.
--
Charles Francis
cha...@clef.demon.co.uk
bilge
>
>The diagrams do not individually state what happens in a given
>interaction, but describe the possibilities of what may happen. There
>are an infinite number of possibilities, but that is not the same as an
>infinite number of photons.
>
process as a whole. Since terms fall off in importance rather
rapidly in orders of (1/137), you can get away with calculating
most everything using a small number of diagrams. The ward identities
provide the means of selecting the self-energy contributions at
each order. You are trying to read more into what qed says about
what "really" happens than it does. What "really" happens has
no meaning where you want it to. No observable can tell you
what's under the hood. Charge renormalization in qed is perfectly
legitimate. If you were questioning renormalization in qcd, I
wouldnt be able to agree or disagree. I find it somewhat suspect,
but havent spent enough time looking at that to say much.
>In this instance the question is of fundamental importance to the
>interpretation of qed, and quantum mechanics in general. I believe that
>is the main interest of the person wanting a non-rigorous description of
>physical theory. To give such a person a non-rigorous description, and
>be sure that it is right, someone has to work on the rigorous
>description. At the moment it seems that academics and lecturers refuse
>to acknowledge the need for such treatments in field theory. I regard
>that as a matter of supreme incompetence, as well as professional
>negligence in view of what the founders of the subject such as Dirac and
>Feynman had to say on the subject.
I've read through your paper and when I get the chance, I'll
make comments if I have any. There is an irony though in your
support of for the concept of discrete space (and which has
numerous other adherents). The most enthusiastic support is
probably from people you would view in the same light of
negligence as the two you mention. Most notaably, john wheeler
supports the idea because it's a requirement to communicate
information.
Frank Wappler
> Frank Wappler wrote:
Can you?
Frank Wappler
> Frank Wappler [wrote]:
> > > > 1/2 = 1/2 + 1/2 - 1/2, 1/2 =/= 1/2 - 1/2, and 1/2 =/= 1/2 + 1/2;
> > > > only variations in notation.
> > > So you found the minimum through a variation
> > > of the plausible action?]
> > I can't quite follow how your questions relates to my statement
> > (could you sketch this in a little more detail, please),
> /
> \delta \ (P)dt = 0
> /
Well, as far as this addresses the equalities and inequalities that I
stated above, I used
0 = 0, 1/2 = 1/2 and 1/2 =/= 0 as plausible ("actions");
along with symbols/operators "+" and "-" which can be defined
in reference to those plausible relations.
Would this approach constitute a "minimum" of some sort?
> > [but yes: at least in principle, I can find stationary values
> > of "potential", i.e. I can find "the most probable potential",
> > from given measured coordinate relations as constraints;]
> > I find it plausible to express "action" as a sum of
> > the expression for "potential", and the (operator?) expression C
> > which corresponds to the measurement procedure by which the
> > coordinate constraints have been determined,
> > times a Lagrangean multiplier;
> dplausible plausible
> --------- - ----- = 0
> dpedantic dpedantic DOT
More plausible, IMHO:
dplausible dplausible
--------- - ----- DOT = 0
dpedantic dpedantic DOT
Apparently we agree at least that "plausible" is a
function of "pedantic" and "pedantic DOT";
and that its stationary values are of interest.
> > and I find it plausible to express "potential V" for given C
> > through an estimate based on the Robertson-Schrödinger relations:
[
> > (Ca~Ca) (Cb~Cb) >= 1/4 (((Ca~Cb) - (Cb~Ca))~((Ca~Cb) - (Cb~Ca))) == V,
]
> Did Phys Rev Q¹ accept it?
Dunno. Phys. Rev. already accepted
L == -1/4 (((Ca~Cb) - (Cb~Ca))~((Ca~Cb) - (Cb~Ca))) + m Ca + const.
(Phys. Rev. 96, 191, 1954, eqs. (11) with (9), using the notation above);
and linear algebra is surely unambiguous.
So far about which actions I find plausible, and why.
Which action do you find plausible, and why?
Regards, Frank W ~@) R
p.s.
> > How would you measure whether you've "found the axion", or not?
> That's why I said dont find it.
> Finding it is much harder and people expect it.
This doesn't seem to address my question. And if it did nevertheless,
then it's ambiguous. No surprise then that obtaining a measurement/find
through such an ambiguous procedure appears hard.
> > Also, whichever "things" you may attempt to find and to identify
> > based on their relations with each other, aren't they at least
> > _singly connected_ with each other, and hence spin 1/2?
> Unless this isnt the case, of course.
Well - the "things" for which this isn't the case are those which
are not even singly connected and related to any "thing" else.
Without any relation there seems to be no way for
distinguishing them from ... noise.
> > (You know Dirac's - or was it Feynman's? - survivalist trick:
> > How to hold a bowl with _any_ sort of stew and to examine it [
> > from all sides before eating, without turning food back
> > in the process already; and with one palm glued to your back?)]
> Did he measure the bowl?
Its rim. Twice.
> > Which measurement procedures did Descartes suggest?
> Mostly, one that works [...]
Which one was that?, and in which sense "does it work"?
bilge
>Dunno. Phys. Rev. already accepted
>
I assumed they'd want more context before publishing it. It's
pretty remarkable to get a couple of lines accepted. Must have
thrilled the referees, too.
>So far about which actions I find plausible, and why.
>Which action do you find plausible, and why?
>
I'm not planning to take the bait again.
>
>> > Which measurement procedures did Descartes suggest?
>
>> Mostly, one that works [...]
>
>Which one was that?, and in which sense "does it work"?
I'm not certain. He gave part of it to xeno who should have
been here with the information ages ago, but it's been reported
he may never finish the trip.
Charles Francis
> >
> >The diagrams do not individually state what happens in a given
> >interaction, but describe the possibilities of what may happen. There
> >are an infinite number of possibilities, but that is not the same as an
> >infinite number of photons.
> >
> No. They state the relative contribution of that diagram to the
> process as a whole. Since terms fall off in importance rather
> rapidly in orders of (1/137), you can get away with calculating
> most everything using a small number of diagrams. The ward identities
> provide the means of selecting the self-energy contributions at
> each order. You are trying to read more into what qed says about
> what "really" happens than it does.
I do not think so. In my paper qed is derived from first principles,
what I read into it is based on those first principles, not on qed
itself. All I am saying is that the relative contribution of a diagram
is a contribution to a probability calculation, given that we do not
know what happened. In any given case there is a diagram which describes
exactly what happened, but we do not know which one, just like an
ordinary probability. The reason we do not get the familiar probability
relationship, and get the quantum relationship, is that, in addition to
the diagram itself, we also do not know what happened to the individual
particles in the environment, and apparatus. In his published papers,
Mark Hadley also derives quantum law from "continuous time-like curves"
in gr. My core argument is very similar to his, but I think mine is more
general.
>What "really" happens has
> no meaning where you want it to. No observable can tell you
> what's under the hood.
That is true, but the requirement for logical consistency of
interpretation is very powerful.
>Charge renormalization in qed is perfectly
> legitimate. If you were questioning renormalization in qcd, I
> wouldnt be able to agree or disagree. I find it somewhat suspect,
> but havent spent enough time looking at that to say much.
>
I do not question the need for renormalisation, but I do not accept
infinite renormalisation. I
>
> >In this instance the question is of fundamental importance to the
> >interpretation of qed, and quantum mechanics in general. I believe that
> >is the main interest of the person wanting a non-rigorous description of
> >physical theory. To give such a person a non-rigorous description, and
> >be sure that it is right, someone has to work on the rigorous
> >description. At the moment it seems that academics and lecturers refuse
> >to acknowledge the need for such treatments in field theory. I regard
> >that as a matter of supreme incompetence, as well as professional
> >negligence in view of what the founders of the subject such as Dirac and
> >Feynman had to say on the subject.
>
>
> I've read through your paper and when I get the chance, I'll
> make comments if I have any.
I look forward to it.
> There is an irony though in your
> support of for the concept of discrete space (and which has
> numerous other adherents). The most enthusiastic support is
> probably from people you would view in the same light of
> negligence as the two you mention. Most notaably, john wheeler
> supports the idea because it's a requirement to communicate
> information.
>
I do not include Wheeler in my tirade against attitudes which I have
found in my personal contact with certain professors, but these
attitudes seems to reflect the "orthodox" view. For example, although
Feynman says the maths of qed is dodgy, and thinks that the divergences
arise from a technical inaccuracy, when I set about demonstrating that
this is in fact the case, I was told that Feynman, Schwinger, et al were
very clever people and could not possibly have made a mistake. When I
set about reconciling field theory with the foundations of quantum
mechanics and started to show that it describes point-like particles, (
no wave structure) in the absence of a background of space-time, I was
told that if Dirac and the founding fathers could not resolve such
questions, no one should try.
--
Charles Francis
cha...@clef.demon.co.uk
Frank Wappler
> > > > > Dont find the axion. Since it's supposed to exist, you
> > > > > can unexplain strong cp-violation by not finding it.
Sorry, I had misread "axion" as "anyon".
(And I had stuck to my misconception in the last couple of posts,
adding 1/2 + 1/2 - 1/2,
quipping about Dirac's - or was it Feynman's? - survivalist trick, etc.
Did you notice my mistake?)
In any case, my question still remains:
> > > > Frank Wappler [wrote:]
> > > How would you measure whether you've "found the axion", or not?
or, as you seem to prefer:
Are there measurement procedures to find/identify particles
such that they are guaranteed _not to be_ "axions"?
Regards, Frank W ~@) R
p.s.
> Frank Wappler [wrote:
> > Phys. Rev. already accepted
> > L == -1/4 (((Ca~Cb) - (Cb~Ca))~((Ca~Cb) - (Cb~Ca))) + m Ca + const.
> > (Phys. Rev. 96, 191, 1954, eqs. (11) with (9), using the notation
... as shown earlier.)
And apparently as postulates, no less.
> I assumed they'd want more context before publishing it.
About postulates?
AFAIK, there was enough thrill in how Yang and Mills _used_ them.
bilge
>or, as you seem to prefer:
>Are there measurement procedures to find/identify particles
>such that they are guaranteed _not to be_ "axions"?
>
Yes. Use apparatus that cant detect them. Failing any assurance
that you're going about it wrong, and could accidently find
one, you can turn the power off, which is almost a sure thing.
Few particles can flip the power switch on a CAMAC crate in
self-promoting their discovery. Powering off the equipment leaves
you with a large uncertainty in what you've measured proportional
to the equipment powered off so, you can be certain of not finding
anything by turning off all of the equipment.
Frank Wappler
> Frank Wappler [wrote]:
> > or, as you seem to prefer:
> > Are there measurement procedures to find/identify particles
> > such that they are guaranteed _not to be_ "axions"?
> Yes. Use apparatus that cant detect them.
> [...] you can turn the power off [...] so you can be certain
> of not finding anything
That doesn't address the question: How to _find/identify_ particles
such that they are guaranteed not to be "axions".
Also, how would one "power off" certain particularly essential
apparatus components, for instance protons?
AFAIK, they don't seem to carry along their individual VMX chassis
with the self-evident little red button.
> Failing any assurance that you're going about it wrong
... lends assurance that in some respect I'm going about it right.
bilge
>That doesn't address the question: How to _find/identify_ particles
>such that they are guaranteed not to be "axions".
>
Therin lies the reason not start down the slippery slope of
measuring things that could produce outliers which would
have to be included in any data for publication. I dont
see a way around being "had" by the statistics without
a large financial investment in erasers.
>Also, how would one "power off" certain particularly essential
>apparatus components, for instance protons?
>AFAIK, they don't seem to carry along their individual VMX chassis
>with the self-evident little red button.
>
Have you checked for a breaker? Someone with small fingers
would help in flipping them off. Soon as they stop moving,
put them on the first VME bus out of the lab, then barricade
the branch highway.
>> Failing any assurance that you're going about it wrong
>... lends assurance that in some respect I'm going about it right.
Which means you'll find a particle you'd rather not, hence
you have to be assured you dont perform the experiment correctly.
Frank Wappler
> Frank Wappler [wrote:
> > bilge/serling ...
> > didn't] address the question: How to _find/identify_ particles
> > such that they are guaranteed not to be "axions".
> > > Failing any assurance that you're going about it wrong
> >... lends assurance that in some respect I'm going about it right.
> Which means you'll find a particle you'd rather not,
So far we've failed to establish even how to _search_ for any particle,
not to mention for no axions. And I'd rather fail to tell you what
I've found, than let you fail telling me what you seek.
> hence you have to be assured you dont perform the experiment correctly.
Precisely that's for what I've been asking Moataz Emam a while ago
in this thread.
But since you flip protocols faster than a VXI hand can shake his head ...
... I remain unassured about why not to invest in erasing them outliers.
bilge
>
>So far we've failed to establish even how to _search_ for any particle,
>not to mention for no axions. And I'd rather fail to tell you what
>I've found, than let you fail telling me what you seek.
>
>Precisely that's for what I've been asking Moataz Emam a while ago
>in this thread.
>But since you flip protocols faster than a VXI hand can shake his head ...
>... I remain unassured about why not to invest in erasing them outliers.
>
often be salvaged from otherwise uninspiring data. Often, too
excellent.
Frank Wappler
> Frank Wappler [wrote]:
> > I remain unassured about why not to invest in erasing them outliers.
> I'd be remiss to persuade you not to do so. Excellent results may
> often be salvaged from otherwise uninspiring data. Often, too excellent.
You're being negligent already by failing to prescribe
how you'd "salvage results", and how you'd determine their "excellence".
> > I'd rather fail to tell you what I've found,
> > than let you fail telling me what you seek.
> That's easy. I wasn't seeking anything.
I see. Apparently bilge/serling can be inspired by bilge/serling alone ...
Jim Carr
bilge/serling wrote:
}
} Frank Wappler [wrote]:
} > Which particular intuition do you invoke when trying to measure
} > the value of a pairwise distance, "x", in some experimental trial?
}
} The fact [that your] ruler isnt bent.
In article <7u2omj$f...@mary.csc.albany.edu>
fw7...@csc.albany.edu (Frank Wappler) writes:
>
>What do you mean by "a ruler being bent, or not bent"?
By what pairwise coordinate relations do you ensure that,
trial by trial, article by article, that the word "you"
means the same thing? Do you require Einstein sync to
guarantee that "bent" means the same thing each time you
used it in that sentence? Is it reproducible?
By what pairwise measurement process can we be sure that the
word "being" that appears on my computer display is the same
as the word that was on yours when you composed this article
some time ago? Is it the same if different (yet identical,
so are they different) electrons were used to form the letters?
What pairwise coordinate relations can be used to verify this
before we move on to the next word?
--
James A. Carr <j...@scri.fsu.edu> | Commercial e-mail is _NOT_
http://www.scri.fsu.edu/~jac/ | desired to this or any address
Supercomputer Computations Res. Inst. | that resolves to my account
Florida State, Tallahassee FL 32306 | for any reason at any time.
Frank Wappler
> By what pairwise coordinate relations do you ensure that,
> trial by trial, article by article, that the word "you"
> means the same thing?
AFAIU it doesn't. It's a variable.
Jim Carr
I again request that you notice followups set to the newsgroup
where you have been discussing this 'relavitity' issue.
Jim Carr wrote in article <7v2ma3$2c3$1...@news.fsu.edu> that:
|
...
| In article <7u2omj$f...@mary.csc.albany.edu>
| fw7...@csc.albany.edu (Frank Wappler) writes:
| >What do you mean by "a ruler being bent, or not bent"?
|
| By what pairwise coordinate relations do you ensure that,
| trial by trial, article by article, that the word "you"
| means the same thing? Do you require Einstein sync to
| guarantee that "bent" means the same thing each time you
| used it in that sentence? Is it reproducible?
|
| By what pairwise measurement process can we be sure that the
| word "being" that appears on my computer display is the same
| as the word that was on yours when you composed this article
| some time ago? Is it the same if different (yet identical,
| so are they different) electrons were used to form the letters?
|
| What pairwise coordinate relations can be used to verify this
| before we move on to the next word?
In article <7vdv10$8...@mary.csc.albany.edu>
fw7...@csc.albany.edu (Frank Wappler) writes:
>
>AFAIU it doesn't. It's a variable.
Just checking. Thus you believe that your own remarks are
not reproducible upon transmission. Fascinating.
Frank Wappler
> I again request that you notice followups set to the newsgroup
> where you have been discussing this 'relavitity' issue.
As before, I am noticing that the followups have been set
excluding sci.physics.electromag, and sci.physics.particle
but to sci.physics.relativity alone.
Since I had been asking about the selection of measurement
procedures, _including_ the selection of the Yang-Mills form
of "the most probable potential", as is conventionally made
by posters to sci.physics.electromag and sci.physics.particle,
I'd like those posters to have access to my reply to your
checks and questions about how I formulate my questions, too.
I set followups accordingly.
> Frank Wappler [wrote]:
> > Jim Carr wrote:
> > > By what pairwise coordinate relations do you ensure that,
> > > trial by trial, article by article, that the word "you"
> > > means the same thing?
> > AFAIU it doesn't. It's a variable.
(So is "it", btw.)
> Just checking.
You're welcome.
> Thus you believe that your own remarks are not reproducible
> upon transmission.
Of course I don't assume this a priori; nor that someone else
could reproduce all relations that any one of my own
remarks/observations/statements has with any other of my own
remarks/observations/statements.
However, occasionally I do observe replies by others, i.e.
I observe remarks/observations/statements containing at least
some of the same relations which were contained in a subset
of what I had remarked/observed/stated, too; along with others.
From such pairs of (sets of) mutual remarks/observations/statements
one can derive a measure of transmission ("quality") of observers
wrt. each other. One may even _expect_ that "transmission quality
doesn't change a lot, soon". But, given relevant observations
in the next trial, one might as well _measure_ again.
> Fascinating.
No: elementary.
Regards, Frank W ~@) R
p.s.
> > > [What pairwise coordinate relations can be used to verify this
> > > before we move on to the next word?]
None, by definition:
pairwise coordinate relations that could be used to verify this
are those that have been _determined_ by this in the first place.
Others, which are derived independently, cannot be used to verify.
Jim Carr
fw7...@csc.albany.edu (Frank Wappler) writes:
>
>Jim Carr wrote:
And since the rest is an altered version of what I wrote, I
observe that Wappler proves my point when he writes
>From such pairs of (sets of) mutual remarks/observations/statements
>one can derive a measure of transmission ("quality") of observers
>wrt. each other.
A comparison of pairs of remarks shows that the one you attribute
to me is not what I wrote. Thus we must conclude from this comparison
of message pairs that you are not reading what others write.
QED.
Frank Wappler
> Frank Wappler [wrote]:
> > Jim Carr wrote:
> And since the rest is an altered version of what I wrote
... which my records show as my reply, along with quotes of those parts
of your post which my reply addressed specificly ...
> I observe that Wappler proves my point when he writes
> > From such pairs of (sets of) mutual remarks/observations/statements
> > one can derive a measure of transmission ("quality") of observers
> > wrt. each other.
Namely:
> A comparison of pairs of remarks shows that the one you attribute
> to me is not what I wrote.
You didn't recognize my quotes of what you wrote?
What a lousy transmission! Which pairs did you observe and compare?
> Thus we must conclude from this comparison of message pairs
> that you are not reading what others write. QED.
Thus one may determine that you don't write what others read.
Which wouldn't have to be.
Jim Carr
fw7...@csc.albany.edu (Frank Wappler) writes:
>
... the same silly troll.
See my final reply in sci.physics.relativity.
Frank Wappler
> ... the same silly troll.
> See my final reply in sci.physics.relativity.
And there:
> Frank Wappler wrote:
> > You didn't recognize my quotes of what you wrote?
> > What a lousy transmission! Which pairs did you observe and compare?
> "| By what pairwise measurement process can we be sure that the
> | word "being" that appears on my computer display is the same
> | as the word that was on yours when you composed this article
> | some time ago? Is it the same if different (yet identical,
> | so are they different) electrons were used to form the letters?
> |
Sorry, I didn't quote that in the preceding post.
Still a lousy transmission!
> | What pairwise coordinate relations can be used to verify this
> | before we move on to the next word?"
Yes, two segments of this string are the same as I quoted
a while ago in the same thread, i.e.
> > > > > [What pairwise coordinate relations can be used to verify this
> > > > > before we move on to the next word?]
> > None, by definition:
> > pairwise coordinate relations that could be used to verify this
> > are those that have been _determined_ by this in the first place.
> > Others, which are derived independently, cannot be used to verify.
> describe the synchronization process and the specific measurement
> process you mean by "observe" and the pairwise fashion in which
> you "compare" both the processes and the things processed
I require a number a terms a priori in order to formulate any
nontrivial description in the first place, among them "observation",
"same", "not same", and "and".
But therefore I cannot give nontrivial and noncircular descriptions
_of_ those terms.
Instead, I can merely observe _that_ I observe and compare my observations.
Further I can describe that I collect same observations into "sets"
(each set containing those observations which belong to the same "state"),
or "unions" of sets, that I call the set of those observations which are
same among (not same) sets the "intersection" of those sets; and I can
for instance describe how I'd "order" those sets/states:
Union( A, B ) =/= A, and Union( A, B ) == B is_same_as A < B;
A < B, Union( A, B, C ) =/= Union( A, B ), and
Union( A, Intersec( B, C ) ) =/= A, is_same_as A < C.
That's the basis for how I state any descriptions;
because I believe that a description ought to refer to what I myself
or what anyone else can observe; and remaining required terms appear
a minimum necessary for expressing (nontrivial) relations
of observations with each other.
How do you state descriptions?, i.e. how did you select the terms
upon which your descriptions are based?
Do you believe that you can give descriptions of those terms in turn?
(Btw., note the relevance of those considerations for the selection
of the Yang-Mills form of "the most probable potential".)
> your silly troll about pairwise measurement
Call it what you know.
As an experimental physicist I call it essential. Frank W ~@) R
p.s.
> actually read some experimental papers.
Can do!
Having read (parts of)
A. Zeilinger, Experiment and the foundations of quantum physics,
Rev. Mod. Phys. 71 (2) S288, 1999,
I even can formulate questions about it:
Fig. 3 gives a sketch of an experimental setup, involving detectors
and a lense; along with a description of experimental procedures
and results for a particular set of trials.
Was detector 1 covered by a (horizontal) slit during those trials,
or was it not (as the sketch seems to imply)?
(Note that this set of trials is not necessarily the same
as the set whose results are given in histogram Fig. 4.)
If detector 1 was not covered by such a slit in the relevant trials,
then do the obtained results allow a determination of optical properties
of the lense, wrt. an ideal lense (which the sketch seems to imply)?
Otherwise, if detector 1 was covered by such a slit in those trials,
then do the results allow a determination of any optical properties
of the lense, wrt. an ideal lense (which the sketch seems to imply),
besides focal length and image length which the sketch gives already?