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A FAREWELL TO COPENHAGEN?
Posted on Sunday, August 08, 2004 @ 13:06:44 UTC by vlad
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by John G. Cramer (from The Alternate View):
This column is about experimental tests of the various interpretations of quantum mechanics. The question at issue is whether we can perform experiments that can show whether there is an "observer-created reality" as suggested by the Copenhagen Interpretation, or a peacock’s tail of rapidly branching alternate universes, as suggested by the Many-Worlds Interpretation, or forward-backward in time handshakes, as suggested by the Transactional Interpretation? Until recently, I would have said that this was an impossible task, but a new experiment has changed my view, and I now believe that the Copenhagen and Many-Worlds Interpretations (at least as they are usually presented) have been falsified by experiment.
The physical theory of quantum mechanics describes the behavior of matter and energy at the smallest distances. It has been verified by more than 70 years of experiments, and it is trusted by working physicists and regularly used in the fields of atomic, nuclear, and particle physics. However, quantum mechanics is burdened by a dismaying array of alternative and mutually contradictory ways of interpreting its mathematical formalism. These include the orthodox Copenhagen Interpretation, the currently fashionable Many Worlds Interpretation, my own Transactional Interpretation, and a number of others.
Many (including me) have declared, with almost the certainty of a mathematical theorem, that it is impossible to distinguish between quantum interpretations with experimental tests. Reason: all interpretations describe the same mathematical formalism, and it is the formalism that makes the experimentally testable predictions. As it turns out, while this "theorem" is not wrong, it does contain a significant loophole. If an interpretation is not completely consistent with the mathematical formalism, it can be tested and indeed falsified. As we will see, that appears to be the situation with the Copenhagen and Many-Worlds Interpretations, among many others, while my own Transactional Interpretation easily survives the experimental test.
The experiment that appears to falsify these venerable and widely trusted interpretations of quantum mechanics is the Afshar Experiment. It is a new quantum test, just performed last year, which demonstrates the presence of complete interference in an unambiguous "which-way" measurement of the passage of light photons through a pair of pinholes. But before describing the Afshar Experiment, let us take a backward look at the Copenhagen Interpretation and Neils Bohr’s famous Principle of Complementarity..."
Read the whole article at: www.analogsf.com
An interesting discussion on this topic at: www.solohq.com
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Re: A FAREWELL TO COPENHAGEN? (Score: 1)
by mojo on Monday, August 09, 2004 @ 12:49:24 UTC
(User Info | Send a Message) | The way I see quantum mechanics is this. The properties (energy, charge, field, etc) of the quantum system are distributed over all the states defined and described by the wave function. I believe that this is a continuous distribution, with actual quantum or sub-quantum connectlvity between the eigenstates. This implies a completely continuous wave function. When an interaction ( of sufficient strength and asymmetry) occurs, a localization of the property distribution of the system takes place and the wave function appears to collapse. This apparent collapse is just a reorganization of the property distribution of the system, due to the exact nature of the interaction. Since we due not Know the exact nature of the interaction, it appears probabilistic, but is actually totally determined, within the limits of the uncertainty principle.
As an example, consider a quantum system that can described as being in state A or B with equal probability. This would mean that the properties of the system are equally distributed over states A and B, with a very small amount constituting the state corresponding to the connectivity. When this interacts with another non-quantum (already localized) system whose exact structure is unknown, then there is a 50/50 chance for the localization of the original system to occur in either state A or B. If the quantum properties of the second system are non- localized and known, localization probabilities for the first system will be different.
In the double slit;it experiment, the probabilities are totally dependent on the photon's property distribution at the point of interaction with the screen, since the exact structure of the screen is unknown and it presents an equal opportunity for interaction with the various portions of the photon state distribution.
In this view, there is no abrupt collapse of the wave function. There is just a continuous change in the wave function due to the localization and de-localization of the property distribution of the systems involved.
Entanglement implies a partial or complete overlap of the property distribution and/or the connectivity distribution. It could also imply a secondary connectivity distribution.
mojo |
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Re: A FAREWELL TO COPENHAGEN? (Score: 1)
by mojo on Monday, August 09, 2004 @ 14:06:57 UTC
(User Info | Send a Message) | Hi all.
An addition to my previous comment.
In the double slit experiment the photon always goes through both slits (properties distributed in a two state form).The property distribution then takes on the normal (interference} density form as the two state form expands from the slits.. This always disallows a which-way determination since it does not exist.
mojo |
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Re: A FAREWELL TO COPENHAGEN? (Score: 1)
by vlad on Wednesday, August 11, 2004 @ 22:13:23 UTC
(User Info | Send a Message) http://www.zpenergy.com | Message:
Date: Tue, 10 Aug 2004 18:41:10 -0700
From: Jack Sarfatti
Subject: Re: Thumbs down on Ashfar's QM Experiment
Yes I realized that. Am forwarding this to all in case there is any
misunderstanding of the context. :-)
On Aug 10, 2004, at 1:55 PM, Waldyr A. Rodrigues Jr. wrote:
> Dear Jack,
>
> Afashar's quantum bombshell is a subtitle of the N.S. paper entitled
> Quantum Rebel, which describes Afashar`s experiment. I did not say in
> the message I sent to you (with the copy of that paper) that I agree
> with Afashar's conclusions, and of course, I do not agree with him. I
> note here that I sent a message to him asking for the details of the
> experiment (since I would like to write a comment, inn the spirit of
> Basil`s one) but he did not reply.
>
>
>
> Now, I simply sent the paper for several people which the purpose of
> exposing what a journal like N. S. is publishing (and eventually to
> serve as a test for their knowledge of Quantum Physics). Now, N.S. is
> only a popular science magazine, but may scientific journals are also
> publishing papers with absurd errors of all kinds. Want one example?
> Read the new papers by M.W.E. at the Found. Phys. Lett.
>
> Best regards,
>
> Waldyr
>
On Aug 10, 2004, at 11:12 AM, Jack Sarfatti wrote:
>
> On Aug 10, 2004, at 3:53 AM, Basil Hiley wrote:
>
>> Jack,
>>
>> Thanks for the copy of the New Scientist's article about Afshar's
>> experiment. Unfortunately it is no challenge to Bohr's position.
>> How on
>> earth does he know the photons arriving at detector 1 come from
>> pinhole 1
>> when both pinholes are open? You cannot use ray optics in the region
>> where
>> the light from the two pinholes overlap so you cannot draw any such
>> conclusion.
>
> Yes, Fred Alan Wolf also pointed this out. I did not read it carefully
> - was too busy at that moment, but since Waldyr sent it I thought it
> should be passed on.
>
>>
>> Lets look at the claim a little more closely. Afshar is quoted as
>> saying
>> "According to my experiment one of the key assumptions about quantum
>> theory
>> is wrong." Ok what assumption? The article doesn't say. It mutters
>> something about Bohr and goes on to say "When faced with a classical
>> apparatus these mysterious quantum entities will either show a
>> particle-like
>> or a wave-like face." Where has this sloppy thinking come from?
>>
>> Bohr never said any such thing. What Bohr actually said was
>> 'However, since
>> the discovery of the quantum of action, we know that the classical
>> ideal
>> cannot be attained in the description of atomic phenomena. In
>> particular,
>> any attempt at an ordering in space-time leads to a break in the
>> causal
>> chain, since such an attempt is bound up with an essential exchange of
>> momentum and energy between the individuals and the measuring rods and
>> clocks used for observation; and just this exchange cannot be taken
>> into
>> account if the measuring instruments are to fulfil their purpose.
>> Conversely, any conclusion, based in an unambiguous manner upon the
>> strict
>> conservation of energy and momentum, with regard to the dynamical
>> behaviour
>> of the individual units obviously necessitates a complete
>> renunciation of
>> following their course in space and time'. [Bohr, Atomic Theory and
>> the
>> Description of Nature, pp. 97-8, Cambridge University Press, 1934]
>>
>> Notice the phrase 'following their course in space and time'. This is
>> not a
>> discussion about particles 'behaving only like waves or only like
>> particles'. It is about 'following' or 'looking at' the process using
>> some
>> suitable instrument. So if you 'look at' each photon as it passes
>> through
>> one pinhole you won't get an interference pattern. Even the Bohm
>> approach
>> agrees with that.
>>
>> OK after that little rebuff we finally come to Afshar's real claim.
>> It is
>> that his experiment is "recording the rate at which photons are coming
>> through each pinhole". If this statement was correct then it would
>> imply
>> that "there should be no interference pattern" where the beams
>> overlap.
>> "But there is, Afshar says".
>>
>> Sure there is an interference effect simply because Afshar's
>> experiments do
>> not 'follow' anything and they do not 'look at' each photon as it
>> passes
>> through a pinhole. He is simply collecting and counting the
>> distribution of
>> photon arrivals at his two detectors. Then he makes inferences about
>> what
>> could possibly be going on and concludes, incorrectly that a photon
>> detected
>> in the 'photon detector for pinhole 1' came from pinhole 1. However
>> that
>> conclusion is based on the assumption that the rays emanating from
>> pinhole 1
>> arrive at the 'photon detector for pinhole 1'. But the ray picture
>> breaks
>> down as soon as you enter the region of overlap of the two beams and
>> you
>> cannot conclude that the photon entering pinhole 1 arrives at the
>> 'photon
>> detector for pinhole 1'. You haven't measured which pinhole each
>> photon
>> passed through so you have not contradicted Bohr.
>>
>> Unfortunately Afshar's conclusion, "According to my experiment one
>> of the
>> key assumptions about quantum theory is wrong" is incorrect. His
>> conclusion
>> is wrong simply because he doesn't understand the physical optics
>> that lies
>> behind the experiment he is doing.
>>
>>
>> On 6/8/04 9:00 pm, "Jack Sarfatti" wrote:
>>
>>> bcc
>>>
>>> Thanks Waldyr
>>>
>>> I have not had time to really think deeply about what is being
>>> claimed
>>> here.
>>> Is the original paper online?
>>> Superficially, this seems to confirm Bohm's theory of both IT
>>> particles
>>> and BIT pilot waves?
>>> However, I do not yet really understand the logic of his experiment
>>> i.e., how he is getting "through which slit" information in the first
>>> stage. I simply have not had enough to time to think about it yet.
>>> :-)
>>>
>>> Both Valentini and Cramer understand the issues well and they seem to
>>> be for it. I simply have not had enough time to digest it
>>> completely. A
>>> tens of seconds attention is not enough time for this deep issue. Of
>>> course, Bohmians have thrown away Bohr's view a long time ago -
>>> keeping
>>> some of it but seen in a different way.... |
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Re: A FAREWELL TO COPENHAGEN? (Score: 1)
by mojo on Thursday, August 12, 2004 @ 12:41:10 UTC
(User Info | Send a Message) | Since the experiment has demonstrated, albeit indirectly, that interfernce is taking place during the experiment, then this implies that the wavefunction at each detector must contain components from both slits.
If it did not contain components from both slits, then you could not have demonstrated interference.
The wave function of a single photon after passing through the slit(s) is a superposition of the photon passing through slit A and the photon passing through slit B.
The wave function does not collapse at the wire. This shows that the wave function is still intact.
When the wavefunction reaches the len(s) and/or detector(s) it is still a superposition of the photon passing through slit A and the photon passing through slit B.
Therefore, at each detector there is information from each leg of the wave function and you can not unambiguously determine which leg of the wavefuntion has facilitated the collapse at the detectors
mojo.
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