Is There a Time Order Behind Quantum Entanglement According to Antoine Suarez?

[debra]

Let me just toss out this mishmash of material because I happen to be aware of it. The last stuff (Brukner and Kofler) is from Zeilinger's group obviously. Diederik Aerts is a very interesting guy, knew John Bell well when he (Aerts) was a young post-doc at Geneva, and conducted workshops with Alain Aspect at the time Aspect was setting up his first experiment.

.....

John C. Baez and Mike Stay:

Physics, Topology, Logic and Computation:
A Rosetta Stone

Category theory is a very general formalism, but there is a certain special way that physicists use categories which turns out to have close analogues in topology, logic and computation. A category has objects and morphisms, which represent things and ways to go between things. In physics, the objects are often physical systems, and the morphisms are processes turning a state of one physical system into a state of another system -- perhaps the same one. In quantum physics we often formalize this by taking Hilbert spaces as objects, and linear operators as morphisms.

http://math.ucr.edu/home/baez/rosetta.pdf

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Diederik Aerts and Marek Czachor:

Cartoon Computation: Quantum-like computing without
quantum mechanics

We present a computational framework based on geometric structures. No quantum mechanics is involved, and yet the algorithms perform tasks analogous to quantum computation. Tensor products and entangled states are not needed — they are replaced by sets of basic shapes. To test the formalism we solve in geometric terms the Deutsch-Jozsa problem, historically the first example that demonstrated the potential power of quantum computation. Each step of the algorithm has a clear geometric interpetation and allows for a cartoon representation.

http://tinyurl.com/bjvsds

slightly different version:

http://arxiv.org/pdf/quant-ph/0611279v2

and:

Quantum Aspects of Semantic Analysis and Symbolic Artificial Intelligence

Modern approaches to semanic analysis if reformulated as Hilbert-space problems reveal formal structures known from quantum mechanics. Similar situation is found in distributed representations of cognitive structures developed for the purposes of neural networks. We take a closer look at similarites and differences between the above two fields and quantum information theory.

http://arxiv.org/pdf/quant-ph/0309022v4


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Časlav Brukner & Johannes Kofler

Classical world arising out of quantum physics under the restriction of coarse-grained measurements

Conceptually different from the decoherence program, we present a novel theoretical approach to macroscopic realism and classical physics within quantum theory. It focuses on the limits of observability of quantum effects of macroscopic objects, i.e., on the required precision of our measurement apparatuses such that quantum phenomena can still be observed. First, we demonstrate that for unrestricted measurement accuracy no classical description is possible for arbitrarily large systems. Then we show for a certain time evolution that under coarse-grained measurements not only macrorealism but even the classical Newtonian laws emerge out of the Schrödinger equation and the projection postulate.

http://arxiv.org/pdf/quant-ph/0609079v3

Essentially the same material but adapted from a PowerPoint presentation. Pretty cool:

http://www.fjfi.cvut.cz/workshop/Workshop_Prague_2008/presentations/Brukner_measurements.pdf

Thanks for these references. They showed me (in a shocking way) what little is known about interpreting quantum physics in terms of information.

 

[Ilja]

Hi guys,
I am curious about the work done by Antoine Suarez. I think this is a famous one but I need some more information about this. He concluded :

----------------------------------------------------------------------
The final results

The final results of the experiments with moving measuring devices (see experiments) rule out the possibility to describe the quantum correlations by means of real clocks, in terms of "before" and "after"; nonlocal quantum phenomena cannot be described with the notions of space and time. This means that there is no time ordering behind nonlocal correlations, so the causal order cannot be reduced to the temporal one. Quantum correlations somehow reveal dependence between the events, or logical order. Experiment shows that this dependence, or logical order, is beyond any real time ordering. In the realm of the nonlocal quantum phenomena, things come to pass but the time doesn't seem to pass here.
------------------------------------------------------------------

Is there any critics to this conclusion and his experiment?
Or are we finally concluded that there is no time ordering behind entanglement?
What happened to The interpretation that information is sent backwards in time - is it dead?

Thanks in advance...

It is provable false, because one can use pilot wave theory as a counterexample. This interpretation of QT gives the same predictions as QT but has a well-defined causal ordering in time.

 

[nikman]

It is provable false, because one can use pilot wave theory as a counterexample. This interpretation of QT gives the same predictions as QT but has a well-defined causal ordering in time.

A recent experiment by Nicolas Gisin's group (with which Suarez is informally affiliated) claims that for the Bohmian model to work there'd need to be a superluminal influence operating at a magnitude four times greater than lightspeed.

http://arxiv.org/pdf/0808.3316

 

[DrChinese]

A recent experiment by Nicolas Gisin's group (with which Suarez is informally affiliated) claims that for the Bohmian model to work there'd need to be a superluminal influence operating at a magnitude four times greater than lightspeed.

http://arxiv.org/pdf/0808.3316

I didn't follow what they were saying about that. A Bohmian theory is going to be non-local anyway, So how does providing a lower bound on the "speed of quantum information" (their term) being greater than 10^4c rule out a Bohmian theory?

It's a great experiment by the way, very clever use of fiber optics and the movement of the Earth through space.

 

[nikman]

I didn't follow what they were saying about that. A Bohmian theory is going to be non-local anyway, So how does providing a lower bound on the "speed of quantum information" (their term) being greater than 4c rule out a Bohmian theory?

It's a great experiment by the way, very clever use of fiber optics and the movement of the Earth through space.

It doesn't rule it out imo. They piled serious doubt upon, not disproved. You have to admit a lower bound of 10,000 times light speed for pilot-waves is a big swallow. When you consider those results along with the before-before experimental tests (which Suarez sees as ruling out the Bohm variety of nonlocal realism) it makes Bohmian mechanics seem rather less plausible even than before.

What I wish I understood is why Bohm's is a realistic model not ruled out by Leggett-Garg.

BTW the Zeilinger group challenged the experiment's conceptualization:

http://arxiv.org/abs/0810.4452

and was replied to:

http://arxiv.org/abs/0810.4607

 

[nikman]

I should've said ORDERS OF magnitude in my first post.

 

[DrChinese]

I should've said ORDERS OF magnitude in my first post.

I messed up the same thing and edited my post. The article actually shows a graph of the various lower bounds, with 10,000c more or less being the absolute floor. It rises to about 100,000c at some angle settings. So I would conclude that it is as close to instantaneous as it gets.

As I re-read their conclusion:

"From these observations we conclude that the nonlocal correlations observed here and in previous experiments[1] are indeed truly nonlocal. Indeed, to maintain an explanation based on spooky action at a distance one would have to assume that the spooky action propagates at speeds even greater than the bounds obtained in our experiment."

...I guess they are distinguishing a) "nonlocal" (which is absolutely instantanteous, in keeping with Bohmian types); vs. b) "spooky action at a distance" which involves cause-effect, the transmission of quantum information from Alice to Bob (or vice versa).

In this case, I guess we are putting some constraints on the pilot wave mechanics. In the Bohmian program, there is an absolute time frame and so one of the measurements occurs first (which I will simply label as Alice). So we need to explain how a macroscopic polarizer setting at Alice influences a quantum outcome at Bob, but the setting at Bob does not influence the outcome at Alice (which would have already occurred). Or something, I guess I am still confused.

 

[nikman]

...I guess they are distinguishing a) "nonlocal" (which is absolutely instantanteous, in keeping with Bohmian types); vs. b) "spooky action at a distance" which involves cause-effect, the transmission of quantum information from Alice to Bob (or vice versa).

In this case, I guess we are putting some constraints on the pilot wave mechanics. In the Bohmian program, there is an absolute time frame and so one of the measurements occurs first (which I will simply label as Alice). So we need to explain how a macroscopic polarizer setting at Alice influences a quantum outcome at Bob, but the setting at Bob does not influence the outcome at Alice (which would have already occurred). Or something, I guess I am still confused.

I may be wrong, but if it helps any I think this experiment links all the way back to at least 2001, when Gisin conducted another experiment involving relativistic reference frames and a principle which in those days he called "multisimultaneity". It introduced the before-before configuration (since often referred to by Suarez):

http://arxiv.org/pdf/quant-ph/0110117v2

Here's a Suarez paper from Foundations of Physics last summer, discussing an approach which seems conceptually not dissimilar to the current one:

http://www.dancing-peasants.com/sciphil/Nonlocal_“Realistic”_Leggett_Models...pdf

Same material differently formatted:

http://www.quantumphil.org/SuarezFOOP201R2.pdf"5 Preferred Frame Models

"If one assumes that Bohm’s time-ordered nonlocality belongs to physical reality, one has to cast it into a description using real clocks and accepting the experimental result of the relativity of time. As said above, the essential ingredients of a realistic theory lead naturally to accept that the relevant clocks are those defined by the inertial frames of the beam splitters. In this sense, Bohm’s model [16] is the adequate time-ordered nonlocal description for entanglement experiments with beam splitters at rest. And its natural extension to experiments with beam splitters in motion is the model leading to the prediction that the nonlocal correlations should disappear in the before-before experiment [8, 9, 11, 12]. Therefore, this experiment proves nonlocal determinism in the testable relativistic extension of Bohm’s model [16] wrong."

For anyone who likes material in a colorful graphic format here's a link to a page of Suarez's website. "Is There Time in the Quantum World?" is obviously adapted from a PowerPoint presentation:

http://www.quantumphil.org/presentations.htm

 

[DrChinese]

"5 Preferred Frame Models

"If one assumes that Bohm’s time-ordered nonlocality belongs to physical reality, one has to cast it into a description using real clocks and accepting the experimental result of the relativity of time. As said above, the essential ingredients of a realistic theory lead naturally to accept that the relevant clocks are those defined by the inertial frames of the beam splitters. In this sense, Bohm’s model [16] is the adequate time-ordered nonlocal description for entanglement experiments with beam splitters at rest. And its natural extension to experiments with beam splitters in motion is the model leading to the prediction that the nonlocal correlations should disappear in the before-before experiment [8, 9, 11, 12]. Therefore, this experiment proves nonlocal determinism in the testable relativistic extension of Bohm’s model [16] wrong."

Thanks, this material is very helpful! Starting to fit together. So the pilot wave model imposes a requirement of "absolute time ordering", which the experiment effectively refutes (as much as it can be accepted - see below). This leaves the possiblity of a finite "spooky action at a distance" which exceeds 10,000c, which is the hard to swallow part you mention.

As to the experiment and the subsequent comments by Zeilinger et al, and the response to that: Zeilinger is saying that a more loophole-free version is needed. And Gisin et al say that the experiment was not attempting to close all loopholes, since the experiment was looking for evidence of a preferred frame and found none. They also say the "strict Einstein locality" condition has already been met (by Zeilinger's own work) and does not need to be tested in this format. I have a fundamental disagreement with the requirement of eliminating all loopholes simultaneously anyway. But I can see why Zeilinger would like this condition tested anyway - it quiets the critics. On the other hand, I doubt this experiment will satisfy Bohmians regardless (how could it?) and I am sure we will see more experimental tests of pilot wave theories.

 

[nikman]

Thanks, this material is very helpful! Starting to fit together. So the pilot wave model imposes a requirement of "absolute time ordering", which the experiment effectively refutes (as much as it can be accepted - see below). This leaves the possiblity of a finite "spooky action at a distance" which exceeds 10,000c, which is the hard to swallow part you mention.

As to the experiment and the subsequent comments by Zeilinger et al, and the response to that: Zeilinger is saying that a more loophole-free version is needed. And Gisin et al say that the experiment was not attempting to close all loopholes, since the experiment was looking for evidence of a preferred frame and found none. They also say the "strict Einstein locality" condition has already been met (by Zeilinger's own work) and does not need to be tested in this format. I have a fundamental disagreement with the requirement of eliminating all loopholes simultaneously anyway. But I can see why Zeilinger would like this condition tested anyway - it quiets the critics. On the other hand, I doubt this experiment will satisfy Bohmians regardless (how could it?) and I am sure we will see more experimental tests of pilot wave theories.

That analysis and summary definitely works for me. And it's useful. Thank you. Zeilinger has said he expects loophole-free Bell-type or Leggett-type tests to become available eventually that'll test both the reality and locality assumptions -- separately and simultaneously -- for models that allow for that, including I assume pilot-wave theories. It's clearly important to him. He wants to address the issue of what can be said about a world in which there's demonstrably no such thing as counterfactual definiteness.

He doesn't like many-worlds either, but the only m-w falsification test I know of (that doesn't involve committing suicide) is the one suggested by Rainer Plaga, which a lot of people think wouldn't fly anyway.

 

[Ilja]

I have a fundamental disagreement with the requirement of eliminating all loopholes simultaneously anyway. But I can see why Zeilinger would like this condition tested anyway - it quiets the critics. On the other hand, I doubt this experiment will satisfy Bohmians regardless (how could it?) and I am sure we will see more experimental tests of pilot wave theories.

Sorry, but there is an equivalence theorem: The predictions of pilot wave theories agree with the predictions of SQM.

Whatever is presented as "experimental tests of BM" is nonsense. (It remains to find out at which place the difference between dBB and the "dBB" which is "tested" is hidden. Some variant of search for hidden variables ;-))

And, of course, dBB in the relativistic case needs a preferred frame. Any "relativistic" variant which does not use a preferred frame is not dBB.

 

[Ilja]

Therefore, this experiment proves nonlocal determinism in the testable relativistic extension of Bohm’s model [16] wrong."

[16] refers to:

16. Bohm, D.: A suggested interpretation of the quantum theory in terms of “hidden” variables. I and II. Phys. Rev. 85, 166–193 (1952)

Thus, the author of this paper invents some personal "testable relativistic extension of Bohm’s model", which seems unpublished (once he refers to Bohms original paper and not the extension), and falsifies it. Big deal, and irrelevant.

Pilot wave theories, of course, use a preferred frame in the relativistic domain.

Experimental refutations of pilot wave theories are, at the same time, experimental refutations of SQM. Whatever is presented as "experimental refutation of BM against SQM" is nonsense.

 

[Ilja]

A recent experiment by Nicolas Gisin's group (with which Suarez is informally affiliated) claims that for the Bohmian model to work there'd need to be a superluminal influence operating at a magnitude four times greater than lightspeed.

http://arxiv.org/pdf/0808.3316

For the Bohmian model to work we need (as in classical Newtonian theory) infinite speed of information transfer. Any upper bound for violations of Bell's inequality would falsify pilot wave theories together with SQM.

That would be really interesting. But this result of the Gisin group is simply what is predicted by pilot wave interpretations.

 

[Alfi]

sorry to interrupt everybody throwing papers at each other.

but I'm slow in following, I try , and way back there was this statement that said;

"An elementary quantum system contains one bit of information."

?my question.

If you 'know' it's a 'one'
don't you also 'know' that it is not a 'not-one'?

In binary a 1 also tells me that it is not a 0. Instantly I have two pieces of information about a single bit.

again, sorry to interrupt but the question caught me.

can that not be considered as 'knowing' two somethings of information from a single 'bit'?

 

[nikman]

sorry to interrupt everybody throwing papers at each other.

but I'm slow in following, I try , and way back there was this statement that said;

"An elementary quantum system contains one bit of information."

?my question.

If you 'know' it's a 'one'
don't you also 'know' that it is not a 'not-one'?

In binary a 1 also tells me that it is not a 0. Instantly I have two pieces of information about a single bit.

again, sorry to interrupt but the question caught me.

can that not be considered as 'knowing' two somethings of information from a single 'bit'?

"1" and "Not-0" are synonyms if you only have two binary alternatives, "0" and "1". They're merely different ways of saying exactly the same thing. So it's still just one piece or bit of information.

However ... there's such a thing as a "trit" of information, which is base-3 instead of base-2. That'd be like sunny, rainy or who knows what the weather's like. And now I'm confused.