🚀 go-pugleaf

In article <2d59pc$6...@ginger.csv.warwick.ac.uk>
ma...@csv.warwick.ac.uk (Mr J S Graley) writes:

> But, what if we set up our lab equipment to show both effects? In other words,
> we have a tiny gap, and a source adequate to push, say, averagely 1 photon
> per second through the hole. What happens now?
>
> Do we use some kind of quantum indeterminacy and say they _are_ particles,
> but that they are being deflected randomly by quantum mechanics into a
> pattern which looks rather similar to the pattern you would expect from a
> wave?

Call it a cosmic conspiracy (or complimentarity), but you must note
that you
*can't* produce an experiment that gives you evidence of something
behaving
like a particle and a wave at the same time. This is part of the
problem with
interpretations of QM, the theory gives us so much room to ask all
sorts of
questions of the sort you mention.

Basically you have a couple of choices:
1) QM is complete. I take this to mean that all the physical
information that
   actually *exists* is within the wavefunction as traditionally used.
2) QM is incomplete, ie the opposite of the above.

On the first line (the "standard" interpretation) your question just
isn't
valid, it is in essence meaningless.

The second line lends itself towards an HVT (Hidden Variable Theory)
approach
to QM. Here the complete physical picture would consist of the
wavefunction
plus one or more other variables. The most natural extra variable that
works
is the position of the particle in question. As many will no doubt de
fuming
at the moment, there are lots of "problems" to do with HVTs (to do with
it
needing to be non-local and contextual), but that's another debate.

Manar

In article <2d59pc$6...@ginger.csv.warwick.ac.uk>, ma...@csv.warwick.ac.uk (Mr J S Graley) writes:
> It seems intrinsic to quantum mechanics that one can only understand it to
> a limited degree. The more one knows about the mathematics of quantum
> mechanics, the less one understands what its all about, and vice-versa.

Maybe that is because many physicists keep insisting they have a complete
theory when it is obviously incomplete. It cannot deal with the objective
nonlinear changes that occur in the wave function without resorting to
metaphysical nonsense like the collapse postulate or Everett's many worlds.

>[...]
> Suppose you have a lightbulb, a hole, and a screen. You can demonstrate the
> quantum effect by making the light _very_ dim and using a photomultiplier to
> detect photons. It goes ping!-ping!-ping! and you knowthat light exhibits
> particle effects. The photons cast a perfect shadow of the hole, too. How
> you make the light brighter, but make the hole jolly small. Suddenly
> diffraction becomes noticable, and a pattern appears (just a splodge for
> a single hole, actually), and gets more marked as you shrink the hole.
>
> But, what if we set up our lab equipment to show both effects? In other words,
> we have a tiny gap, and a source adequate to push, say, averagely 1 photon
> per second through the hole. What happens now?

There is no big surprise. We get an interference pattern that is built up
one quantum at a time at whatever rate the particles are being produced.
My simple intuitive explanation is that we have a wave structure that
traverses the gap and forms an interference pattern with itself. This
interference pattern corresponds to the probability that the structure
will change nonlinearly or collapse and interact with the photographic
emulsion so a particle *appears* to be detected at a single point.

>
> Do we use some kind of quantum indeterminacy and say they _are_ particles,
> but that they are being deflected randomly by quantum mechanics into a
> pattern which looks rather similar to the pattern you would expect from a
> wave? [...]

I suspect that particles are nothing more than the focal points of nonlinear
transformations of the wave function. They do not have any other objective
existence. These nonlinear transformations are happening all the time and
are reversible. It is only when they combine through thermodynamics to
form a statistically irreversible macroscopic effect that we have an
observation.

Paul Budnik

In article <1993Nov27.171224.1263@mtnmath.UUCP>,
	paul@mtnmath.UUCP (Paul Budnik uunet!mtnmath!paul) writes:
|In article <2d59pc$6...@ginger.csv.warwick.ac.uk>, ma...@csv.warwick.ac.uk (Mr J S Graley) writes:
|> It seems intrinsic to quantum mechanics that one can only understand it to
|> a limited degree. The more one knows about the mathematics of quantum
|> mechanics, the less one understands what its all about, and vice-versa.
|
|Maybe that is because many physicists keep insisting they have a complete
|theory when it is obviously incomplete. It cannot deal with the objective
|nonlinear changes that occur in the wave function without resorting to
|metaphysical nonsense like the collapse postulate or Everett's many worlds.

By 'objective nonlinear changes' I assume you mean determination of a
characteristic by someone else. I'm not convinced that measurment always
acts to destroy the datum being measured. I therefore agree with you when
you call it 'metaphysical nonsense'. If I am understanding you right, that
is.

|>[...]
|> Suppose you have a lightbulb, a hole, and a screen. You can demonstrate the
|> quantum effect by making the light _very_ dim and using a photomultiplier to
|> detect photons. It goes ping!-ping!-ping! and you knowthat light exhibits
|> particle effects. The photons cast a perfect shadow of the hole, too. How
|> you make the light brighter, but make the hole jolly small. Suddenly
|> diffraction becomes noticable, and a pattern appears (just a splodge for
|> a single hole, actually), and gets more marked as you shrink the hole.
|>
|> But, what if we set up our lab equipment to show both effects? In other words,
|> we have a tiny gap, and a source adequate to push, say, averagely 1 photon
|> per second through the hole. What happens now?
|
|There is no big surprise. We get an interference pattern that is built up
|one quantum at a time at whatever rate the particles are being produced.
|My simple intuitive explanation is that we have a wave structure that
|traverses the gap and forms an interference pattern with itself. This
|interference pattern corresponds to the probability that the structure
|will change nonlinearly or collapse and interact with the photographic
|emulsion so a particle *appears* to be detected at a single point.

So the _intensity_ of the light is actually the _probability_ of a particle
like entity manifesting itself. So this is really a statistical argument
saying 'we know about the average behaviour of photons but not what each
individual one will do'.

|>
|> Do we use some kind of quantum indeterminacy and say they _are_ particles,
|> but that they are being deflected randomly by quantum mechanics into a
|> pattern which looks rather similar to the pattern you would expect from a
|> wave? [...]
|
|I suspect that particles are nothing more than the focal points of nonlinear
|transformations of the wave function. They do not have any other objective
|existence.

Then what does exist? I prefer the approach of starting from the premise
that paricles definitely _do_ exist, and then saying if we find that a
particle is equivilent to something of doubtful _actual_existance_, e.g.
a wave function, then this represents a good argument fo saying that the
wave function is a fundamental aspect of existance.

In other words, if the paricles, which do exist, are made of something else,
then that exists, too.

~TGN

--
             Beware the GREAT NAME, for he is the devil's horn.
                 He flames for lust, or greed, or a laugh.
     Ye, he will criticise his own brethrin, to gain his SysOp's Password.
                Fear him, for he is the harbinger of flames.

In article <2d8dva$r...@borage.csv.warwick.ac.uk>, ma...@csv.warwick.ac.uk (Mr J S Graley) writes:
> [...]
> |There is no big surprise. We get an interference pattern that is built up
> |one quantum at a time at whatever rate the particles are being produced.
> |My simple intuitive explanation is that we have a wave structure that
> |traverses the gap and forms an interference pattern with itself. This
> |interference pattern corresponds to the probability that the structure
> |will change nonlinearly or collapse and interact with the photographic
> |emulsion so a particle *appears* to be detected at a single point.
>
> So the _intensity_ of the light is actually the _probability_ of a particle
> like entity manifesting itself. So this is really a statistical argument
> saying 'we know about the average behaviour of photons but not what each
> individual one will do'.

This is not what I mean at all. I do not think particles exist. My
speculation is that space time and any field function are all discrete.
If you discretize the wave equation you will get a system that can closely
approximate the original continuous differential equation. There will also
be nonlinear chaotic like solutions because you must introduce nonlinearity
in discretizing the field values. I think these nonlinear solutions may
generate a form of quantum collapse.

If you start with an initial disturbance in a discrete model it will
initially diffuse as it does in a continuous model. At some point this
type of diffusion cannot continue. The levels of intensity will be too
small relative to the minimum discrete level. Instead the disturbance will
break up into separate structures that continue to move apart. It is
likely that there will be stable dynamic structures similar to
attractors in chaos theory. These structures will under some conditions
be able to transform into one another and these nonlinear transformations
would be an objective reversible form of quantum collapse.

These structures can only interact as units because of their stability.
All interactions must involve a transformation from one stable structure
to a different stable structure. This is responsible for the quantization
of interactions.  When one of these transformations occur it will have a
focal point in state space. There does not have to exist *anything* at
that focal point. It is an imaginary point in state space that appears to
be the point from which the new stable structure emerged. The higher
the gradient of the wave function (and space in time) at some location
the more likely it will transform with a focal point at that location.
This is the source of the probabilistic interpretation of the wave function.
The uncertainty principle is nothing more than a mathematical constraint
on the `sharpness' of this focal point in state space that is not that much
different then similar constraints on focal points in classical physics.

>[...]
> |I suspect that particles are nothing more than the focal points of nonlinear
> |transformations of the wave function. They do not have any other objective
> |existence.
>
> Then what does exist?

The wave function exists. Particles have a sort of objective existence in that
when the wave function diffuses sufficiently it will break up into separate
stable structures that each embody the energy of a single particle. They also
exist as the structures that mediate the transfer of energy with a field.
They do not exist as point like structures.

> I prefer the approach of starting from the premise
> that paricles definitely _do_ exist, and then saying if we find that a
> particle is equivilent to something of doubtful _actual_existance_, e.g.
> a wave function, then this represents a good argument fo saying that the
> wave function is a fundamental aspect of existance.

Why do you say the wave function is of doubtful existence. The Klein Gordon
or relativistic Schrodinger equation for a photon is identical to the
wave equation for the electromagnetic field. One can say the
wave equation for a photon is its electromagnetic field. There is little
doubt of the existence of the electromagnetic field.

> In other words, if the paricles, which do exist, are made of something else,
> then that exists, too.

Of course that is true to some degree. However I think the field function
is primary and particles are secondary effects.

Since the assumption that space time and the field function is discrete
implys that special relativity is only approximately correct I always like
to mention that Einstein near the end of his life thought that such a model
may be needed.

        I consider it quite possible that physics cannot be based on the
        field concept, i. e., on continuous structures. In that case
        *nothing* remains of my entire castle in the air gravitation
        theory included, [and of] the rest of modern physics.
                -- Einstein in a 1954 letter to Besso, quoted from:
                "Subtle is the Lord", Abraham Pais, page 467.

Paul Budnik

ma...@csv.warwick.ac.uk (Mr J S Graley) writes:

>But, what if we set up our lab equipment to show both effects? In other words,
>we have a tiny gap, and a source adequate to push, say, averagely 1 photon
>per second through the hole. What happens now?

>Do we use some kind of quantum indeterminacy and say they _are_ particles,
>but that they are being deflected randomly by quantum mechanics into a
>pattern which looks rather similar to the pattern you would expect from a
>wave?

Yes, more or less.

The wave gives the probability that a photon will land at a particular
point; this is the case even when there's only one photon flying at the
screen.  As for what actually happens when the photon is detected at that
spot, and the state in which the photon's position is indeterminate
seemingly turns into one in which the photon is strongly localized...
that's a rather large can of worms, about which physicists love to argue.
--
Matt    	01234567   <--  Indent-o-Meter (mod 8)
McIrvin         ^       	Harnessing tab damage for humanity!

ma...@csv.warwick.ac.uk (Mr J S Graley) writes:
>
>But, what if we set up our lab equipment to show both effects? In other words,
>we have a tiny gap, and a source adequate to push, say, averagely 1 photon
>per second through the hole. What happens now?

We can't, but we can do something almost as good.  If we cause pair production
to occur  we could observe the wave properties of, say, the electron, and
the particle properties of the positron at the same time.
--Ray Cote

There's no government like no government.