Exploring the Bohmian Interpretation: A Rational Realist's Perspective

[confusedashell]

I'd love to discuss and learn more about the Bohmian Interpretation as I'm almost completely convinced this is "THE" one and only correct interpretation explaining what is REALLY going on in the quantum world.
It save's realism, it can account for the fact of nature called nonlocality, it saves quantum physics from metaphysical philosophical speculation and bring it back to PHYSICS where it belongs and it's simple and elegant.

I know a lot of people have jumped on the mainstream Many Worlds, who also believe in a objective reality, yet live in denial of nonlocality and slit their own wrists with Occam's razors. (Vanesch:P)

Jokes aside:

After a few email exchanges with Goldstein and Travis Norsen, I've learned a lot, but feel there is a lot more to learn.
So if anyone in here is a rational realist(Bohmian:P) and want to chat I'd be very interested :)

 

[Demystifier]

Wellcome to the club confusedashell!
If you make a search through my posts, you will see that I already said a lot about Bohmian mechanics (BM).
My main research preoccupation is to make BM consistent with relativity, quantum field theory and string theory.
In addition, unlike most of the Bohmians, I am trying to find a way to make an experimental test of BM.
For a complete list of my professional contributions to BM see
http://xxx.lanl.gov/find/quant-ph/1/AND+au:+Nikolic_H+abs:+OR+OR+Bohm+Bohmian+string/0/1/0/all/0/1

 

[Demystifier]

This is a joke (made up by me) involving a discussion between a creationist, a mainstream physicist, and a bohmian.
Dialog one:

creationist: I think God created the Universe and everything in it.

mainstream physicist: I cannot prove that he hasn't, but it is conceptually much simpler to adopt the physical view according to which all events in the Universe are governed by simple and elegant mathematically formulated physical laws.

creationist: Simpler? I was styding physics as well, and I was even able to understand these physical laws, and I appreciate that they agree with experiments, but still, these laws are far from simple. My view that God simply created the Universe and everything in it is much simpler. Therefore, by Occam razor, I adopt the simpler theory that does not need all these complicated laws of physics.

mainstream physicist: OK, your view is technically simpler, but I don't like it because it's still too mysterious to me. My scientific view is not that mysterious.

creationist: Maybe my view is mysterious, but we who believe that God created the Universe represent the majority. You the scientists who believe that the creation of the Universe is correctly explained by the physical laws represent the minority.

mainstream physicist - to himself: Yes, but the majority does not allways need to be right.
Dialog two:

mainstream physicist: I think the wave function collapses when a measurement is performed.

bohmian: I cannot prove that it doesn't, but it is conceptually much simpler to adopt the bohmian view according to which all events in the Universe are governed by simple and elegant mathematically formulated bohmian laws of motion.

mainstream physicist: Simpler? I was styding Bohmian mechanics as well, and I was able to understand it, and I appreciate that it agrees with experiments, but still, it involves one additional guiding equation absent in standard QM, so it is more complicated than standard QM. My view that the wave function simply collapses when the measurement is performed is much simpler. Therefore, by Occam razor, I adopt the simpler theory that does not need this guiding equation.

bohmian: OK, your view is technically simpler, but I don't like it because it's still too mysterious to me. My bohmian view is not that mysterious.

mainstream physicist: Maybe my view is mysterious, but we who believe that the wave function collapses represent the majority. You the bohmians who believe that the Universe is correctly explained by the guiding equation represent the minority.

bohmian - to himself: Yes, but the majority does not allways need to be right.

 

[Demystifier]

Bonus question: Is the mainstream physicist consistent with himself?

 

[peter0302]

I've said before that the Copenhagen Interpretation is a mix between creationism and agnosticisim. :)

 

[Demystifier]

I've said before that the Copenhagen Interpretation is a mix between creationism and agnosticisim. :)

 

[confusedashell]

Ah great demystifier, I've think I've read some criticism on MWI by you.
Didn't know you we're a bohmian though.
I just saw your topic "what if bm is correct", nice.

What I don't get with MWI'ers is how they can take such a drastic step when it's not needed or put on us by nature.
From everything experimentally proven, experienced, de-Brogile-Bohm seems to have been just right.

 

[RandallB]

the Bohmian Interpretation … I'm almost convinced this is "THE" interpretation explaining what is REALLY going on in the quantum world.
It save's realism,
it can account for the fact of nature called nonlocality,
it saves quantum physics from … … and it's simple and elegant.

I feel there is a lot more to learn.
So if anyone in here is a rational realist (Bohmian:P) ….

David Bohm was very clear that his BM interpretation was Non-Local.

Although, some might reinterpret BM in a manor that attempts to “account for the fact of nature called nonlocality” with what might be described as a BM version of “local”. Such a reinterpretation must do so with a unrealistic super-deterministic version of reality.

Thus with respect to efforts to eliminate the mysterious from reality, BM does not. BM is no less mystic than oQM and to date has provided explanations that are no more complete than oQM explanation just as Niels Bohr predicted back in the 20’s.

Nothing at all wrong with pursuing work in BM views.
But just to be clear, contrary to what is implied in your post; BM has yet to demonstrate that as a QM interpretation it is any more complete than oQM or other QM interpretations. And the “rational realist (Bohmian:P)” veiw certainly is not an Einstein “Local & Realistic” view.

Side Note: When you use the notation (xxx:P) as in “(Vanesch:P)” & “(Bohmian:P)”; what does that mean? Can you provide a translated example or explanation?

 

[confusedashell]

What?

 

[peter0302]

Vanesch made a MWI believer out of me. Furthermore, research is starting to show that non-local realistic interpretations cannot account for the quantum results either (I don't think the papers are universally accepted though). If so, then local / non-realist (MWI is the only one AFAIK) is the only thing left.

 

[confusedashell]

So you can honestly say your believing your splitting all the time, that the me you responded to last time, was antoher universe another "me" ?
that's a sad solipsitic existence your living in, one I wouldn't buy into without a good amount of evidence(at this time, there is zero evidence for this, so why waste ur life?)

lol

"research is starting to show that non-local realistic interpretations cannot account for the quantum results either"

links to this research please

 

[peter0302]

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

http://arxiv.org/abs/0704.2529

 

[peter0302]

So you can honestly say your believing your splitting all the time, that the me you responded to last time, was antoher universe another "me" ?

I do. I don't find it sad. I'm a collection of electrons and protons and neutrons, and it doesn't bother me that there are other possible states of those subatomic particles that are possible and therefore exist. If those other states produce "me's" that are different, so what? I'm still "me". It certainly doesn't affect my life any.

I don't ascribe anything special to consciousness other than the electric impulses of my neurons. Therefore I have no problem believing that my "consciousness" is splitting, any more so than I have a problem believing that the electron splits when it goes through a double slit.

I don't know that MWI cannot be proven. It certainly hasn't been disproven. But anyway, who's wasting his life? I'm certainly not going to commit "quantum suicide" to find out if I'm right. :) I don't really have any emotional investment either way. I just find it fascinating.

 

[confusedashell]

Honest and straight forward answer :)

I'll personally drop the lonely solipsitic existence as nothing in the real world points to this psychotic view.
From my view you are the exact same one I have spoken to everytime I visited this forum:)
It's up to you and other MWI'ers to disprove that, and that as we both know is impossible.
So it's really down to philosophical preference.
You seem to have no problem giving up everyone you love, while I see everyone around me as important as me.

 

[confusedashell]

oops double post:

anyway, I got another question: how come we have never seen the splitting, or die when we split across universes that's what makes my mind ponder.
Honestly I find believing in a wave carrying the particle easier to buy int

 

[peter0302]

Whoa! Now you're making some quite unfounded claims. "Psychotic view?" "Giving up everyone love?" It has nothing to do with that! It's hardly psychotic - it's quite rational. It's the natural result of believing that the wave function never collapses. And on the contrary I'm not giving up anything. My life is unaffected. I still keep the ones I love just fine. If anything, it gives me comfort that this reality is not the only possible one - some better, some worse, but none more important than the other. And it's also the ONLY quantum interpretation that explains why we're all here. (The answer is that we happen by chance to be in that universe in which we're all here; there are others where we're not; there are others still where there's no Earth at all; others where there never was a big bang).

 

[confusedashell]

Uhm, Bohmians would say that bohm's single universe view is the result of believing the wave function never collapse.
And, only interpretation explaining why we're here?
WHAT?
MWI'ers and Bohmians both have same explanation here, except there's only 1 universe, infinitely many times simpler.

Your not fighting a CI proponent here, I believe in a real objective universe just like you.


I'm not calling YOU psychotic.
Just I think your view is psychotic just as I would say a solipist is close to psychotic, eventhough u can't "disprove" solipsism.
Go to a psychiatrist and tell him during ur session that u believe u have splitted universe and spoke to 5000 versions of him.
He'll probably agree with my view. No offense :)

 

[jms5631]

Bohm's interpretation seems to be an excellent attempt at preserving some semblance of classical sensibility in QM, and may yet hit on some fundamental truth in nature. However, the violation of relativity is too heavy a cost to incur for an interpretation in my opinion. At this stage of scientific progress, no one has any decisive way of resolving the interpretation issue. MWI is just an attempt to eliminate the ill defined process of measurement and wavefunction collapse, and illuminate the hidden reality the many posit must underlie QM. It is successful in adhering to the mathematical formalism of QM, without introducing added on postualtes that do not appear in Schordinger's equation. As a physics student I find it useful in thinking about the Quantum theory as it stands today, but I'm far from sure that it is anything more than a useful tool to think about QM(in fact I doubt it is). You should look into the strict decoherence approaches advanced by Zurek, I think they're closer to what your look for than BM. Also, I'm not sure how you see MWI as solipsism, Deutsch seems to think it is the quintessential anti soliptic theory.

Peter, I'm not sure I understand how the nature article supports MWI. The results of the experiments, which are very debatable still it seems, seems to suggest that aspects of both locality and realism need to forfeited. Zeilinger seems to favor something I have seen called the information interpretation of QM, and is a critic of MWI. Perhaps I'm missing something but I fail to see how the paper supports MWI, though I think it delivers a blow to Bohm. In my opinion Zeilinger is one of the brightest minds in the field, and I look forward to his follow up on this work.

 

[confusedashell]

Deutsch seems to think a lot of things that are pure speculative:)
The reason he views MWI as anti solipstic is because it's a objective reality, he says the exact same about Bohm.
I'm talkinga bout the consequence of MWI if it was true, it would mean u were never with the same people, never really any TRUE friends, family nothing... that's what I mean with solipsitic type lonely existence.


I talked to 2 experts on Bohm and Bell, both seem to see the paper in nature as not affecting bohm in anyway.

 

[jms5631]

You very well may be right with regards to the Zeilinger experiment... There certainly is far from a concensus. I think it is safe to say that Bohm has not been falsified catagorically. But there are conceptual problems with Bohm that make it, in my opinion, an unlikely explantion of fundamental truth. That is not to say your idea of the world is wrong... As I said before I think Zurek's dcoherence apporach satisfies your conception of reality entirely without the messy implications of Bohm. I'm far from convinced that Zurk has demonstrated the process of which quantum state the wavefunction decoheres to, but that's another debate. Penrose's objective collapse with the introduction of gravity is another viable prospect(this is where my money is). By doubting Bohm, I'm not saying that the idea of mind independent objective reality(without splitting) is wrong, just that I don't think Bohm gets you there.
However, in MWI I still don't think you end up with "solipsism". If person A splits than they split into a vast multitude of descendant copies of a single subjective state. There is not original, only descendant copies, all of which are equally that same person. All the people in you branch are descendannt copies of the same people who have been there your entire life. There is no justifiable way you can say they aren't.
Further, they is an array of intepretation of MWI itself. Some like Deutsch favor the splitting world hypothesis. Others, like Weinberg use the other worlds as statistical methods of calculating probabilty. Hawking's universal wavefunction is an interesting merger of MWI and quantum cosmology, and he posits our universe as being by far the most probable, with the probability of quantum transitions being almost zero. Hence, no splitting an no need to concern yourself with the other worlds

 

[confusedashell]

Well, there's no way I can't say there is a God, but most likely there isn't.
So until anyone prove this psychotic theory that we split 24/7 to new universes, I'll go with the universal single universe view as the fundamental truth.

Sure you got the weird thing about nonlocality, but honestly, what's more "weird and less likely"?
magical splitting, or faster than light signaling?

The reason I like Bohm, is that it's the most simple explanation out.
Not that simple means beyond doubt correct, but as for now, Bohm most likely is the correct one.
MWI has just as much objections and problems as Bohm.
All I know is that a single objective universe independant of mind is what we should aim for when that's all nature points to.
have you observed any other universes lately? or split into one of them? No ofcourse not, it's a ludacris idea.

another thing comes to mind here: the whole many worlds parallel universe **** is pure speculation, like heaven/hell. nothing in nature hints towards this.

Antony Valentini explains greatly why he thinks MWI is probably wrong and how it by mistake was thought up to begin with.

http://www2.philosophy.ox.ac.uk/misc/everett/Valentini%20-%20Pilot_wave.wmv

 

[peter0302]

Just I think your view is psychotic just as I would say a solipist is close to psychotic, eventhough u can't "disprove" solipsism.

Ok, well "psychotic" is objectively the wrong word. MWI is perfectly rational. You can disbelieve it if you want of course, but just throwing out words that aren't even appropriate to your argument doesn't help your point.

And, only interpretation explaining why we're here?
WHAT?

What I mean is, MWI offers an answer to the question "why is the world this way?" or "why are we here?" The answer is that EVERYTHING that can exist does exist, so this is just the existence we happened to land in. No other interpretation can offer that level of simplicity and clarity of perhaps the most difficult philosophical question ever posed.

 

[jms5631]

Hold on, I am not advocating MWI, I doubt it too on a visceral level. I'm only saying that it is conceptually sound, adeheres to the present quantum formalism, and provides a sensible image of QM that is in line with the predictions of QM. That's all I'm sure of. Bohm also makes equivalent predictions, but are you really willing to permit a violation of relativity, which has been rigorously proven? Bohm is not your only viable alternative to QM. If the fundamental unified theory of the world is not enitirely quantum in nature than this whole convo. is for nothing anyway. You can keep Bohm if you like, but you probally won't find a lot of support in the physics community. There are other viable interpretations out there, that I think you may find even more to your liking. I suggest reading Roger Penrose's "The Emperor's New Mind" and Lee Smolin's "The Trouble with Physics" to help articulate those intuitive issues you seem to have with QM.

 

[confusedashell]

Sure, "psychotic" is a word I use because, when bringing up MWI to any rational normal non-speculative-hobby-phycisist he'll call you psychotic.
The cop out card "everything that can exist does exist" is too cheap, I can say the same about bohm, everything that exist exist the way it does because it was the only way it could due to the Bohmian universe's determined evolution.
See? the argument is worthless, Bohm and MWI stand equal there.

JMS: I agree that Bohm runs into issues with relativity, I asked Travis Norsen (bell expert) on this very topic a few weeks ago.

His e-mail response to me was (hope he don't mind me posting this here):


Indeed,
a precise formulation of Bohm's theory really requires that there be a
preferred foliation of space time, i.e., a preferred frame of reference,
i.e., an ether. So in that sense, yes, Bohm's theory is inconsistent
with relativity. But that is no reason to reject Bohm's theory. For
Bell's theorem proves that *any* theory which agrees with what is
observed in certain experiments will have to have a similar sort of
non-locality. Thus, the non-locality is revealed not as some abberrent
feature of Bohm's theory on the basis of which one should reject the
theory, but rather as a fact of nature. Now, this makes it sound like
relativity is false -- which may indeed be the case. But it is a little
more subtle than that. What exactly relativity does and doesn't require
vis a vis "locality" is controversial. And there are some hints of a
certain type of theory which is non-local in the sense required by Bell's
work, but which is still fully relativistic. So it's subtle and tricky
and controversial. But for sure the easiest way to reconcile everything
is to just reject relativity and go back to the old Lorentz style ether
theory (which preserves the Lorentz transformations and pretty much
everything else about relativity that was actually empirically verified
as opposed to philosophical) -- then you get your preferred frame and
there's no space-time type objection to Bohm's theory.



As for "you won't find a lot of support", I'm not so sure, sure the majority is still hanging behind and holding onto CI, and a lot of new kids on the block has pickedup MWI which supports their childhood scifi dreams, also MWI got a very active advocate (David Deutsch), but a lot of people who read and learn Bohm will see it's advantages.
and again, as Vanesch said, Bohm and MWI is all down to philosophical preference, cause neither has provided a experiment which disprove or prove either.
There has been no detection of the pilotwave being a real wave, or any detection of other universes.
Though the wavefunction is really the pilotwave, so it's atleast already in physics, the consequences of a universe splitting, I think would have made our experience very very different, which it doesn't, so therefore, to me Parallel universes is a religious belief, nothing to do with science at all.
NO offense to those who support this crazy interpretation.

 

[RandallB]

What?

What what?
Or did you forget what you meant by the notation “P” in “(Vanesch:P)” & “(Bohmian:P)” as you used it your OP. Just curious to understand what your notation means is all.

(side note: the Edit function allows you to delete a double post if wish )

As to the criticism of MWI as a indicating “a sad solipsistic existence”.
As a Local Realist I find the Super-determinism required for BM to appear ‘local’ implies no less “a sad solipsistic existence”.
But that only happens when either view attempts to definitively resolve a “local” or “realistic” view from their mutually shared view of a reality that is not both “Local and Realistic”.

Progress on that point is not made by philosophic debate but trying to find a way to make an experimental test, such as Demystifier’s stated goal in post #2.

 

[confusedashell]

How does the BM imply a sad solipstic existence?
Your in the same universe you were born in, with the same parents and all other people, never splitting :)
Your never alone, your always with the same loved ones.

Also, who says Bohm requires SUPER determinism?

The notations was meant as smileyes :P :D ;D ;P ;) :) :p

 

[peter0302]

Sure, "psychotic" is a word I use because, when bringing up MWI to any rational normal non-speculative-hobby-phycisist he'll call you psychotic.

Wow, you make some really bold claims about what all rational normal non-speculative-hobby-phycisists think.

 

[jms5631]

The preferred frame of refrence required for Bohm is enough for me to seriously doubt its validity(though not to dismiss it entirely). I think it would be fascinating if hidden variables turned out to have some degree of ontological reality. At this point, I see no reason to prefer it over MWI though, for even if a case can be made for it despite its inconsistency with relativity, it'll always be much less conceptually clean. MWI has no glaring issues of this kind though it does have its share of problems: the splitting is ill defined, the issue of probability, etc.

I agree that people are gravitating away from Copenhagen towards "alternative approaches" and this has given MWI new life. However it is not only MWI people are turn to. Other approaches include objective collapse theories such as Penrose's and GRW. Transactional interpretations are receiving some interest. Tony Leggett's macrorealistic theories have recently been put to the test, though not officially adjudicated either way. Strict decoherence(without MWI) seems to be rather popular. There are many options out there, so even though CI is losing ground (though still is dominant) I don't see Bohm capitalizing on people's dissatisfaction with CI.

 

[peter0302]

Oh I also wanted to add that the Nature article doesn't advocate MWI. My point was that as non-local theoreis are disproven, pretty soon non-realist theories like MWI will be all that remain.

 

[jms5631]

The paper says: "Our result suggests that giving up the concept of locality is not sufficient to be consistent with quantum experiments, unless certain intuitive features of realism are abandoned."
I may be in over my head, but that seems to suggest that features of both realism and locality need to be given up, and MWI is a local theory.

Anyway, this is discussed in another thread (won't let me post the URL for some reason.) It can be found in the archives. The consensus seems to be nothing has been definitively disproven.

 

[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".