sci.physics.research Google Group

Re: Exact value of Hydrogen line?

2008-07-24T19:25:15Z

In terms of the 21 cm hydrogen line,
[link]
"This transition is highly forbidden with an extremely small probability
of 2.9E−15 /sec. This means that the time for a single isolated atom of
neutral hydrogen to undergo this transition is 1/2.9E−15 or 3.4E14 seconds"

Re: On Penrose's argument against density operators

2008-07-24T19:25:17Z

Hello Chris,
Thank you for raising that point.
Penrose’s argument is actually linked with his criticism about
decoherence, and about the nature of mixed-states. In fact, his
position appears recurrently throughout the book, sometimes less clear
and, at other times, more clearly stated, a careful reading shows that

Re: photon probability density

2008-07-24T19:25:14Z

I disagree with Neumaier’s conclusion that my Lorentz invariant
construction is inconsistent. Chi is never taken to be independent.
All the states considered are transverse, and (18) just expresses a
rotated transverse state in terms of the chi=0 basis.

Re: Gravitational Redshift On Rotating Disk (and its implications)

2008-07-24T19:25:12Z

Really? I thought Schwarzschild discovered the Schwarzschild metric
only months after Einstein published his gravitational field equation.
Are you claiming Hilbert did it all first?
We seem to have our wires crossed here. I was referring to the
redshift which is (1 - 2GM/R) -!/2
This only acts like twice the Newtonian potential at the relativistic

electric and magnetic fields of a moving point-like charge

2008-07-24T19:25:10Z

By what, if any, methods other than by means of the Lienard-Wiechert
potentials can the electric and magnetic fields of a moving point-like
charge be derived? Any references would be greatly appreciated.
Armin

Re: Gravitational Redshift On Rotating Disk (and its implications)

2008-07-24T02:55:46Z

[ Mod. note: Things like =96, etc. come from the quoted-printable MIME
encoding. Please check that your posts are in plain ASCII to avoid
similar transmission problems. -ik ]
Sorry, I don't understand what you mean by 1=96 or by 2=96 so I don't
understand what your question is.

Schrödinger's Universe

2008-07-23T21:47:34Z

Schrödinger's Universe
One of the very best books, that has recently come out, is Dr. Milo
Wolff's brand new book: Schrödinger's Universe.
I've just now finished reading it and I predict that someday it will be
ranked in importance right up there next to Newton's Principia.
I agree with the premise set forth in this book that this is indeed a

Re: Gravitational Redshift On Rotating Disk (and its implications)

2008-07-23T21:08:32Z

nal
No he doesn't. If we are in a gravitational field we can describe it
by Tensors. We do not observe the Universe revolving round us. If you
are on a disc you observe your surroundings rotating. You and your
surroundings have an instantanous Lorenz transformation.
I think that the confusion is due to a faulty understanding of Mach's

Re: Gamma Ray Gun

2008-07-23T21:08:31Z

The absorption of 500keV gammas allows a half intensity beam to arrive
on target at ranges getting on for 100m. How much air ionisation from a
70kW/sq cm is another question. I imagine the beam would be pretty
visible. It is also doubtful that ionised air would stop the gammas any
better than un-ionised.

Re: Gravitational Redshift On Rotating Disk (and its implications)

2008-07-23T21:08:32Z

Each solution or the metric to the Einstein field equations is unique
and describes an independent universe from all other solutions. One
such particular solution that Hilbert had discovered is the famous
Schwarzschild metric in which it is described in general as follows.
ds^2 = c^2 T dt^2 (1 =96 K / r) =96 dr^2 / (1 =96 K / r) =96 r^2 dO^2

Re: The Dirac and Newton-Wigner Velocity Operators and the Speed of

2008-07-23T21:08:31Z

Correction. There is only one velocity operator, just like there is
only one momentum and only one energy operator. The same operator may
have different matrix elements for different choices of basis in the
Hilbert space of states.
If you you found that the "velocity" operator has eigenvalues equal to

Re: Transition from classical continuum mechanics to point mechanics?

2008-07-23T21:08:33Z

Depending on what you mean, it isn't so easy. Sure, you can model a rigid
body moving through a fluid or vacuum using classical continuum mechanics,
but this is very complicated. Why? For starters, the properties of the
continuum are time-dependent (the object moves, so the properties of the
medium at a point that the object moves through go from vacuum (or fluid)

Wiki Article on Foldy-Wouthuysen Transformation

2008-07-23T21:08:32Z

In response to a fair amount of recent discussion about Foldy-Wouthuysen
on sci.physics.foundations, someone suggested that a Wiki article be
started on this topic because at present there is none.
As the primary provocateur of this discussion, I have taken a crack at
getting the ball rolling on such an article, which is at:

Re: On Penrose's argument against density operators

2008-07-23T16:24:16Z

The state vector is even more crippled than that. In an open system
formalism, one can still talk about the reduced density matrix of
system + environment pure states. These reduced density matrices do
not admit factorization into an outer product of state vectors. I.e.
there are no natural reduced state vectors, though people keep trying

Re: Expected value

2008-07-22T21:00:47Z

As an addendum/illustration to my previous reply, suppose that the
initial state is |psi>, and one measures position X to get result x.
From this information, what is the best estimate one can make of the
momentum P? One finds
p_w = Re{ <x|P|p> / <x|p> } = (hbar/2i) [ psi'/psi - (psi'/
psi)*] ,