Where to buy a Double-Slit Experiment setup
alf
Is there any company selling double-slit experiments kit? Any variety
will do although I prefer those which can emit one photon or electron
at a time. I'd like to see the interference patterns after hours of
such single particle emission.
Victor Diego
Try your local camera store. A good digital sensor captures
photons over a small area.
As the exposure increases from zero, the image does not appear
as a "faded" copy of the original scene, but rather as a random
pattern of scattered points. As more and more light is admitted,
a copy of the original scene appears.
By recording images of increasing exposures beginning with zero,
you can see the original scene being formed from a random
pattern.
alf
I'm interested more in one photon or electron at a time emission
because I'd like to know what happens to the photon between the
emitter and the slits. Does it split as in Many Worlds Interpretation
or does the photon remain as a particle or does it just disappear. The
double slit setup in front of me can make me reflect on it more
intimately.
Victor Diego
>
> I'm interested more in one photon or electron at a time emission because
> I'd like to know what happens to the photon between the emitter and the
> slits. Does it split as in Many Worlds Interpretation or does the photon
> remain as a particle or does it just disappear. The double slit setup in
> front of me can make me reflect on it more intimately.
>
Find a better avocation. To set up the double-slit experiment
in a basement or garage would require considerable resources
and expertise. Unless you are very wealthy, it would not be feasible.
Between the emitter and the slit, the photon (or other particle)
is indeterminate and described by the superposed wave functions.
It doesn't exist as a particle (a particle has a definite position)
nor does it disappear (it cannot fall out of existence).
At the detector a sampling (of sorts) takes place. The particle
is found to be at a certain location. Because its position is
no longer indeterminate, the wave function is said to "collapse."
(It becomes essentially a delta function.)
Wave function collapse seems untenable to a lot of people, and so
the Many-Worlds interpretation was created to avoid this collapse
by assuming that all possible outcomes actually occur but each
within a separate universe.
None of these interpretations are necessary, however, if all
we desire is a correct result for practical purposes.
alf
> On Wed, 19 Jan 2011 18:42:04 -0800, alf wrote:
>
> > I'm interested more in one photon or electron at a time emission because
> > I'd like to know what happens to the photon between the emitter and the
> > slits. Does it split as in Many Worlds Interpretation or does the photon
> > remain as a particle or does it just disappear. The double slit setup in
> > front of me can make me reflect on it more intimately.
>
> Find a better avocation. To set up the double-slit experiment
> in a basement or garage would require considerable resources
> and expertise. Unless you are very wealthy, it would not be feasible.
>
> Between the emitter and the slit, the photon (or other particle)
> is indeterminate and described by the superposed wave functions.
> It doesn't exist as a particle (a particle has a definite position)
> nor does it disappear (it cannot fall out of existence).
When the particle is a buckyball composed of 60 atoms. It's hard to
imagine it doesn't exist as a buckyball when it leaves the emitter,
this is why 60% of physicists believe in Many-Worlds Interpretation
now because it's easier to imagine the particle (buckyball) always
existing particle (buckyball) but the world doubles and the particle
or buckyball passes thru both slits (of the two worlds) at the same
time. If you don't believe in Many Worlds. Do you really believe the
buckyball just cease to be buckyball as it leaves the emitter?
Anyway. What I'm planning to do is to create a pure molecule with nano
function that has memory and can store what it sees as it travels
between the slits and emitter so I can know once and for all what
happens in between.. Of course first I have to prepare the nanotech
molecular electronic in pure state so it is in coherence and
superposition capable and small enough so its debroglie wavelength is
large enough..
Victor Diego
>
> When the particle is a buckyball composed of 60 atoms. It's hard to
> imagine it doesn't exist as a buckyball when it leaves the emitter,
>
What makes you think that it can be imagined?
The device that does the imagining is the human brain, and
this device has been molded by evolution to perform only
certain kinds of tasks. The visualization (or imagination)
of the quantum world is not a part of these tasks.
> is why 60% of physicists believe in Many-Worlds Interpretation
I prefer to make no interpretations. Only the results matter
and results are obtainable without interpretations.
> If you
> don't believe in Many Worlds. Do you really believe the buckyball just
> cease to be buckyball as it leaves the emitter?
>
It doesn't cease to be. Nothing at all "happens" to the buckyball.
It's nature never changes. Only the wave function which describes
the state of the buckyball changes.
You have been conditioned to think only of localized and definite
entities as the form of all material existence. This view has
been superseded. Matter may appear to be particulate under
certain conditions and it may appear to be something else under
other conditions. Bur matter does not change, only the appearance
changes.
So your main task is to stop expecting to matter to be a
particle, because it never is a particle.
>
> has memory and can store what it sees
>
The act of "seeing" is destructive and cannot allow a pure
quantum system.
But then I certainly don't know everything -- not even close.
There will always be surprises.
alf
So as the particle leaves the emitter, it shapeshifts into another
form that is not 3D but on higher configuration space of the wave
function? Actually I tend to believe this is what happens. But many
physicists can't accept it. That is why they believe the particle
remains a particle... that's right.. in Many Worlds the particle just
get duplicated that is why the Wave Function has say two entitites in
superposition.. because they actually occur separately and in
superposition. In Bohmians, the particle remains as a particle too.
When I asked other physicists whether the wave function is a wave of
possibilities. He wrote:
"I don't think it makes sense to say that the components of a
superposition "exist only as possibilities" without explaining what
that means. I only see two things that it can mean: 1. |u>+|v> means
that the there are (at least) two copies of the system, one of which
is in state |u> and the other in state |v>. 2. |u>+|v> doesn't
actually represent the properties of the system, but is just a part of
a mathematical formalism that can be used to calculate probabilities
of possible results of experiments."
Do you believe in the second?? But then, It's not even Copenhagen. In
Copenhagen |u>+|v> actually represents the properties and many
physicists don't believe this anymore.
If Many Worlds is true, the particle indeed remain a particle, isn't
it... can't you accept this view? Why?
Victor Diego
> So as the particle leaves the emitter, it shapeshifts into another
> form that is not 3D but on higher configuration space of the wave
>function?
There is no change to the "particle." Only the wave function that
is used to describe the state of the "particle" changes.
When a free electron is captured by an atom, a different wave function
is used to describe the state. The electron does not change.
A similar thing happens in the double-slit apparatus.
> That is why they believe the particle
> remains a particle...that's right.. in Many Worlds the particle just
> get duplicated
In Many Worlds the particle does not remain a particle.
If the particle were to remain a particle, then there would be
no need for quantum mechanics at all. Quantum mechanics exists
because the particle is not a particle and never will be a particle.
Only in classical mechanics can a "particle" be given a definite
position, x, and a definite momentum, q. In quantum mechanics
these "observables" are replaced by operators which act on the wave
functions that describe the particle. Consequently these "observables"
are no longer definite or localized. Many World cannot bring back
the classical particle. It can only rationalize the inherent
uncertainty of QM.
> If Many Worlds is true, the particle indeed remain a particle, isn't
> it... can't you accept this view? Why?
At present I don't accept any interpretations, Copenhagen, Many-Worlds,
or other. They are not necessary for the success of QM.
alf
> On Thu, 20 Jan 2011 14:26:34 -0800, alf wrote:
> > So as the particle leaves the emitter, it shapeshifts into another
> > form that is not 3D but on higher configuration space of the wave
> >function?
>
> There is no change to the "particle." Only the wave function that
> is used to describe the state of the "particle" changes.
What do you mean there is no change to the particle. You mean it
remains as a particle? It contradicts your earlier statements when you
mentioned:
"Between the emitter and the slit, the photon (or other particle) is
indeterminate and described by the superposed wave functions.
It doesn't exist as a particle (a particle has a definite position)
nor does it disappear (it cannot fall out of existence)."
Hmm.. maybe you don't mean "particle" as we normal use. Maybe we have
to do away with the world "particle" at all. Maybe you are referring
to a mystical object which has properties of both particles and waves
and can appear in different guishes. Let's call it wavicle. If so, a
buckyball is not a particle but a wavicle. Now when an object is not
in pure state but in mixed state such as a virus. Can you call it a
wavicle too? Is a virus a wavicle?
Actually a colleage of Heisenberg suggested the word "wavicle" but
even Heisenberg is not convinced it is so when he mentioned:
"No, that solution is a bit too simple for me. After all, we are not
dealing with a special property of electrons, but with a property of
all matter and of all radiation. Whether we take electrons, light
quanta, benzol molecules, or stones, we shall always come up against
these two characteristics, the corpuscular and the undular."
So you are not up against Heisenberg himself. This is why majority of
physicists now believe in Many Worlds so they don't have to challenge
Heisenberg's logic.
Victor Diego
>
> Hmm.. maybe you don't mean "particle" as we normal use. Maybe we have to
> do away with the world "particle" at all. Maybe you are referring to a
> mystical object which has properties of both particles and waves and can
> appear in different guishes.
That's more accurate. But I would avoid the term "mystical."
QM represents the new ordinariness. Also, in the sense that
a "particle" is just a highly localized wave, there really is
no need for the particle concept anymore.
The best way, in my opinion, to grasp QM is to trace its
historical development and to see how the classical
Lagrangian/Hamiltonian had evolved into their quantum
mechanical form.
Also, you should not jump right into the philosophical
consequences of superposition, entanglement, etc.
without first understanding completely the practical
aspects of QM.
Victor Diego
Considering the double-slit experiment, many people are
distressed because the detector seems to compel the universe
into selecting a particular option. To these people, this is
troubling and even nonsensical. The Copenhagen interpretation
provides no relief. The Many-Worlds interpretation provides
some relief.
I find no distress in this behavior. To me, it is as unremarkable
as turning the handle on a gum ball machine. Sometimes I get
a red ball, and other times I get green or yellow or blue.
That's the best that can happen, and so I live with it.
Therefore, I don't require any interpretation for QM events.
All these interpretations, Copenhagen or Many-Worlds, are
"after the fact," or ex post facto. They are completely
unnecessary for the successful application of QM.
alf
No. People who prefers the Many Worlds don't just think it solves the
randomness of the outcomes, but more of what causes the superposition
in the first place, like why the wave function is describing entities
that interfere. And the reason for the interpretation is because there
are two particles, one a duplicate that is why it can pass thru both
slits! This is the more impressive than just showing why it chooses
certain options.
Victor Diego
> This is the more impressive than just showing why it chooses certain
> options.
That may be so, but in science we always have to insist that
a hypothesis be testable. I don't know enough about Many-Worlds
but I don't think that it is testable.
Anyway, as I already indicated, QM can be practiced with or
without interpretations. At present, I prefer to go without.
alf
You familiar with decoherence? Decoherence from the environment can
decohere the superposition. But if the sensor is part of the molecular
particle itself, it can't decohere the setup. When you mention how
seeing can collapse it, you sound like it's a conspiracy of nature to
hide it, and if anyone peeks, it collapses it. But decorehence means
it's just being immersed in the environment.
Anyway, do you know any other device that can do one particle
interference like one photon at a time? I want to do some experiment
like asking a psychic remote viewer to tap into and from the
particle point of view and see what really happens to it
Victor Diego
> When you mention how
> seeing can collapse it, you sound like it's a conspiracy of nature to
> hide it, and if anyone peeks, it collapses it.
"Seeing" is not a magical process. Sensation of any kind involves
direct interaction.
> Anyway, do you know any other device that can do one particle
> interference like one photon at a time?
Most researchers build their own apparatus. Possibly
you can buy, but I would not know from where.
carlip...@physics.ucdavis.edu
> Hi,
If you really want to see one photon at a time, that's going to
cost some money -- you need both a good source and some
really sensitive detectors. TeachSpin sells a set-up -- see
http://www.teachspin.com/instruments/two_slit/index.shtml
-- but it's expensive.
You might look at http://people.whitman.edu/~beckmk/QM/
for ideas of setting something up yourself.
Steve Carlip
joeineas...@gmail.com
mustans...@gmail.com
Archimedes Plutonium
Sorry, Hanson made me do that
Max Keon
http://members.optusnet.com.au/mskeon/dublslit.html
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Max Keon