Is the Bohmian Interpretation the Ultimate Explanation of Quantum Reality?

[Demystifier]

This is the article I was referring to, and it was published in Nature.

http://arxiv.org/abs/0704.2529

The authors themselves admit that their experiment IS compatible with the Bohmian interpretation. Their experiment shows that reality, if exists, must be not only nonlocal but also contextual. The Bohmian interpretation is, indeed, both nonlocal and contextual.

In fact, their experiment only demonstrated a fact that was theoretically known for a long time: that reality, if exists, must be nonlocal and contextual. For theorists - nothing new.

 

[Demystifier]

By the way, does anybody has comments on the posts #3 and #4?

 

[Fra]

something I have seen called the information interpretation of QM

I personally adhere to a kind of information interpretation, but there seems to be many flavours of this too.

My reflection over the bohmian idea of hidden variables and the idea that the explanation of indeterminism is an unknown hidden variable is like this.

One assumes that there exists a variable s that determine the outcome whose ignorance yields the indeterminism by a probability distribution p(s). I'd like to think however, that if we really have no information about s, then neither do we have any information about the a priori measure p().

If we do have that mesure though, the variable isn't hidden IMO. By pulling out an a priori measure we are making an arbitraty choice of a equiprobable set of microstates. If the variable is hidden, I fail to see from where the information of the measure p comes. It's ad hoc.

What I'm thinking is that even measures are information - they aren't innocent. If we say that we have a variable of which we have no information, then one can not argue that there is a natural prior here. We need information to specify the prior, if we take information seriously. This is an old sin however, which also exists in the foundations of statistical mechanics. In a heuristic manner in those textbooks the reader is "convinced" that if we have no information about x, there is a natural prior which suggest that the probability of any x is symmetrical, by appealing to some kind of principle of insufficient reason or other vauge reasonings. IMHO, encoforcing that symmetry is adding information the backdoor. Yes it's very psychological and easy to accept. But when x is a real variable, things turn upside down if we make a simple change of variables. Clearly we expect x to be lables only, so change of variables must not matter. So the preferred choice of parametrization points out as ugly. Would be expect there to be a physical basis for this or not. Or is the continuum the problem? (This is like the generalisation of spacetime diffeomorphisms, if any configuration space is considered to be just labels, then we should be able to relable them at will. But then the priors are not uniform and we no longer seem to have a equiprobable set of microstates, so the labelling doesn't seem entirely unphysical? So if the labelling is a physical process, how do you label and index a hidden variable?)

/Fredrik

 

[peter0302]

It's saying that giving up locality (i.e. Bohm) is not sufficient to explain the results unless you also give up realism (i.e. MWI). It does not say that you cannot have a local, unrealistic theory (i.e. MWI). In fact, MWI is the only one that survives the abandonment of reality. (Well and CI of course but that doesn't count.

 

[confusedashell]

No peter, it's not what it says.
Bohm saves realism, drops locality.
MWI tries to keep realism and locality but nature isn't that way so it's a "wet dream".

 

[Fra]

Perhaps by relaxing the fundamental status of these things I think you can have both emergent :) In the information view, I see both locality and "effective realism" as emergent in special cases.

I think of the processing indexing, and reindexing of events, naturally leads to a locality. Rather than thinking that remote points doesn't affect each other because of locality, one could also imagine that the fact that they don't effect each other (in a particular way) is why they are considered to be far away. If the spacetime is emergent this way, then persistent apparent non-local interactions should deform spacetime in direction of restoring locality, similary to that statistical noise in any direction doesn't change the average, but if odd things start repeating itself, it's no longer odd and the distributions adapt although slow due to inertia against revision.

In the topic of information geometry,the information can induce a distance metric.

"information distance is measured in units of the local uncertainty"

From Information Geometry to Newtonian Dynamics
-- http://arxiv.org/PS_cache/arxiv/pdf/0710/0710.1071v1.pdf

Ariel Caticha share a similar spirit and he toys with allowing information measures to induce a distance metric. I read some of his papers on entropy dynamics and I like his basic spirit, but I didn't understand/agree on his choice of measure. I think his ultimate goal is to derive GR from some universal rules of inference.

http://arxiv.org/PS_cache/arxiv/pdf/0710/0710.1071v1.pdf

Since QM is easier to get into an "information theoretic form", if we could also find classical GR in this form, the unification might be easier to see.

I don't see Ariels papers as the ultimate answers, but they do illustrate a deep suggestive connection and general direction of research. And this I share.

/Fredrik

 

[Moridin]

The Bohm Interpretation

(i) requires the existence of yet undetected and perhaps fundamentally undetectable sub-quantum forces.
(ii) requires superluminal connections violating theory of relativity.
(iii) is terribly ad hoc

Does it have anything going for it besides resting on the dogma of determinism and realism?

 

[confusedashell]

Moridin which interpretration lives up to your views?

This thread is not really a "is bohm right or not?" thread I am looking for propnents of it to learn more about it.
Also I would say any theory resting on realism is better than any refuting realism, if you take realism out of science you take the whole philosophy of science out of science and can just go solipsitic instead

 

[peter0302]

MWI tries to keep realism and locality but nature isn't that way so it's a "wet dream".

You clearly don't understand MWI. And your continued use of childish terms in your arguments significantlly weakens your credibility.

The authors themselves admit that their experiment IS compatible with the Bohmian interpretation. Their experiment shows that reality, if exists, must be not only nonlocal but also contextual. The Bohmian interpretation is, indeed, both nonlocal and contextual.

I understand what they're saying about Bohm in terms of the particles not having angular momentum when emerging from the source. However, Bohm does say the particles have definition position and momentum emerging from the source, and I am sketpcial that Bohm would hold up on that point, even though to my knowledge experiments testing that haven't been done.

I wonder if one could devise an experiment to test it though. Just like the Bell folks realized that angles other than 90 and 45 degrees were necessary to test the quantum predictions against local realistic theories, I wonder if altering the slit width or separation between two double-slits in an entanglement experiment could accomplish the same thing in a position-momentum context.

 

[lightarrow]

Also I would say any theory resting on realism is better than any refuting realism, if you take realism out of science you take the whole philosophy of science out of science and can just go solipsitic instead

I don't agree, you can refute realism of the particle's properties only, but not of the system: particle + measuring apparatus.

 

[confusedashell]

childish terms, one must speak in geek language for you to understand?
if someone use normal words you got a problem understanding the meaning behind them?

 

[peter0302]

I understand you just perfectly. You have a 10th grade understanding of physics, have decided you know everything, and aren't interested in learning more.

 

[confusedashell]

No, I'm eager to learn more, but after months of haering about the different interpretations I've chosen to go with Bohm, therefore this thread where I want to learn more.
Yet, you seem to push the MWI on me like a religious fundamentalist who's seen the light.
You go with MWI I go with Bohm. Ok?

 

[Demystifier]

The Bohm Interpretation

(i) requires the existence of yet undetected and perhaps fundamentally undetectable sub-quantum forces.
(ii) requires superluminal connections violating theory of relativity.
(iii) is terribly ad hoc

(i) It is true that they are undetected yet, but there are proposals suggesting that they could be indirectly detectable in the future.
(ii) It is true that it requires superluminal connections, but it does not necessarily violate theory of relativity (e.g. tachyons).
(iii) It is a subjective argument. If you write the Schrödinger equation in a form that resembles the Hamilton-Jacobi equation, nothing looks more natural than to assume that particles have Bohmian trajectories. In fact, these trajectories were present in the original formulation of wave mechanics introduced by de Broglie. Later de Broglie gave up of these trajectories because at that time he was not able to solve the problem of measurement, but this problem was solved later by Bohm.

 

[Demystifier]

Does it have anything going for it besides resting on the dogma of determinism and realism?

Yes.
For the case of quantum field theory it can be derived even without requirements of realism or determinism, from the requirement of general covariance of quantum theory:
http://xxx.lanl.gov/abs/hep-th/0407228 [Eur.Phys.J. C42 (2005) 365]
http://xxx.lanl.gov/abs/hep-th/0601027 [Int.J.Mod.Phys. D15 (2006) 2171]
This is yet another demonstration that it is not ad hoc.

 

[peter0302]

Yet, you seem to push the MWI on me like a religious fundamentalist who's seen the light.

I've done no such thing and I resent being compared to a religious fundamentalist. More with the name calling.

 

[jms5631]

I have seen articles and interviews regarding the experiment in the Nature article, and exactly what they have claimed to have eliminated still confuses me. It seems like it was a blow to certain types of hidden variable theories, but that's all Zeilinger mentions when talking about it. Even Bohm, he concedes is safe, likely can't be ruled out. I hope this is just the first in a set of further refinements. But, I don't see how objective collapse theories, for instance, would be eliminated by this.

Confused, you reallly need to calm down about MWI. In all probability it will never be enitrely proven nor disproven. It's just a physical interpretation of quantum theory as it stands today, and provides predictions that mesh with experiment. However, so does every other major interpretation. Pick one you feel comfortable with, and go with it. If Bohm does that for you, fine. Be acutely aware of its problems and be ready to defend it. I hope your right and I'm wrong, because of a Bohmian objective reality would be interesting.

 

[Moridin]

(i) It is true that they are undetected yet, but there are proposals suggesting that they could be indirectly detectable in the future.
(ii) It is true that it requires superluminal connections, but it does not necessarily violate theory of relativity (e.g. tachyons).
(iii) It is a subjective argument. If you write the Schrödinger equation in a form that resembles the Hamilton-Jacobi equation, nothing looks more natural than to assume that particles have Bohmian trajectories. In fact, these trajectories were present in the original formulation of wave mechanics introduced by de Broglie. Later de Broglie gave up of these trajectories because at that time he was not able to solve the problem of measurement, but this problem was solved later by Bohm.

(i). Such as?
(ii). Tachyons have never been observed and even if tachyons actually existed, it would not count towards Bohmian interpretation, since tahcyons has a velocity that is always > c. It does not actually pass the speed of light barrier.
(iii). (iii) follows from (i) & (ii).

 

[peter0302]

Actually Tachyons could help Bohm. If you calculate the relativistic velocities needed to send a superluminal signal "instantaneously" as you would need to do in a Bohmian interpretation, the velocity required is equal to c^2/v, where v is the velocity between the sender and receiver. If the sender and receiver are not moving, the necessary velocity is infinite - just as is the velocity of a zero-energy tachyon. If the sender and receiver are moving at the speed of light wrt one another, which, in classical terms, would require inifinite energy to send a message between them, the energy of a tachyon between them (that is, a tachyon moving at 'c') would likewise be infinite.

So, if there were a "quantum boson" associated with Bohmian mechanics, it essentially would obey the equations of a tachyon. We might even call it a "virtual tachyon." Of course, where would the energy for such a boson come from? The infinite energies associated with unnormalized QFT perhaps? Just a thought...

 

[Demystifier]

(i). Such as?
(ii). Tachyons have never been observed and even if tachyons actually existed, it would not count towards Bohmian interpretation, since tahcyons has a velocity that is always > c. It does not actually pass the speed of light barrier.
(iii). (iii) follows from (i) & (ii).

(i). http://xxx.lanl.gov/abs/quant-ph/0406173 [Found.Phys.Lett. 18 (2005) 549]
(ii). Tachyons only served as a counterexample to the frequent (but incorrect) claim that superluminal velocities are not consistent with relativity. To see how exactly nonlocal Bohmian mechanics can be consistent with relativity see the paper above, as well as
http://xxx.lanl.gov/abs/quant-ph/0512065 [AIP Conf.Proc.844:272-280,2006]
(iii). See (i) and (ii)