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Oil droplets guided by pilot waves do not give rise to double-slit interference

quantamagazine.org

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Re: Oil droplets guided by pilot waves do not give rise to double-slit interference

#121

Post by soveran »

abdullahkhalids wrote: post #29
soveran wrote: post #3

All the paradoxes disappear if we use Quantum Field Theory instead of Quantum Mechanics. I would really like someone with deep knowledge on Quantum Theory to explain if something is wrong with a theory that otherwise makes a lot of sense to me. A good read on the topic is the paper "There are no particles, there are only fields" — https://arxiv.org/pdf/1204.4616.pdf

Surprisingly, physicists are very much aware of the field nature of all "entities" in the world, having invented QFT themselves. Even more surprisingly, popular journalistic explanations simplify things considerably, making it seem that the thoughts of physicists are much less refined than they really are. To complete the trifecta of surprises, in the refined thought process of us physicists, using QFT, many problems…

Did you read the paper I linked to?

Re: Oil droplets guided by pilot waves do not give rise to double-slit interference

#122

Post by soveran »

platz wrote: post #4
soveran wrote: post #3

All the paradoxes disappear if we use Quantum Field Theory instead of Quantum Mechanics. I would really like someone with deep knowledge on Quantum Theory to explain if something is wrong with a theory that otherwise makes a lot of sense to me. A good read on the topic is the paper "There are no particles, there are only fields" — https://arxiv.org/pdf/1204.4616.pdf

You can say that the only thing that exists is the quantum wave function, as what basically this paper says (particles are epiphenomena). That is basically hard-line Everettianism e.g. many worlds. There are still problems. QFT does not explain gravity very well either. The paper claims "it's neutral on the interpretations" - it is not. You have the most senior research professor of physics at caltech admitting there…

I don't think the paper assumes a many worlds interpretation.

Re: Oil droplets guided by pilot waves do not give rise to double-slit interference

#123

Post by platz »

soveran wrote: post #122
platz wrote: post #4

Earlier quoted context omitted.

You can say that the only thing that exists is the quantum wave function, as what basically this paper says (particles are epiphenomena). That is basically hard-line Everettianism e.g. many worlds. There are still problems. QFT does not explain gravity very well either. The paper claims "it's neutral on the interpretations" - it is not. You have the most senior research professor of physics at caltech admitting there…

I don't think the paper assumes a many worlds interpretation.

that's what it claims, but that is the only way to make sense of "particles are epiphenomena" + "Thus the Schroedinger field is a space-filling physical field whose value at any spatial point is the probability amplitude for an interaction to occur at that point."

it is saying that the only thing that exists is the quantum wave function

the only theory with a hope of credibility/coherence that says the only thing that exists is the quantum wave function is many worlds.

Re: Oil droplets guided by pilot waves do not give rise to double-slit interference

#125

Post by dotancohen »

rusk wrote: post #105
dotancohen wrote: post #69

Earlier quoted context omitted.

Actually, both you and GP got it wrong. There is no need to speculate what Newton was thinking, it was all recorded. Newton was looking for methods to manipulate (push, pull) objects at a distance without touching them. He had strong ideas about the occult and what we today call black magic, in addition to being an alchemist. He devised that the Earth was manipulating the untouched Moon (capitalized, proper noun) and…

LOL is that for real! Please please can you give me a couple of good citations for that?

Interestingly, I thought that I could simply point you towards Wikipedia [1] and call it a day. However, obviously Newton's viewpoints were controversial in his day and remain so. The controversy is hinted at in Wikipedia, without details. Even the "History of gravitational theory" [2] article completely eliminates this aspect and the "Newton's law of universal gravitation" concentrates completely on the dispute with Hooke.

Many science-related articles on Wikipedia suffer from good-meaning but over-zealous gatekeeping of religious influences on science. So I'll just recommend to you to read a biography or three on Newton. His entire story is fascinating and we can see how tiny events in his childhood (death of father, influence of priest uncle) have affected the history of physics.

[1] https://en.wikipedia.org/wiki/Isaac_Newton [2] https://en.wikipedia.org/wiki/History_of_gravitational_theor... [3] https://en.wikipedia.org/wiki/Newton%27s_law_of_universal_gr...

Re: Oil droplets guided by pilot waves do not give rise to double-slit interference

#126

Post by twtw »

dTal wrote: post #120
twtw wrote: post #58

Bohm's pilot wave theory is interesting to me not because it is so intuitive or tasteful or something, but because it works without sacrificing realism, and thus demonstrates that the Cophenhagen interpretation (neither local nor real) claims strictly more about the nature of the universe than is required by the evidence we have. Nonlocality is established by experiment, non-realism is not. In my experience, this ten…

>I personally favor epistemological interpretations, in which the wave function models our knowledge, and the universe operates via an as-yet-unknown dynamics. Would this not be a 'hidden variable theory' of the type that is ruled out by Bell's theorem?

No, I don't think it would. I don't imply any locality restrictions on the dynamics - they can be arbitrarily strange.

Re: Oil droplets guided by pilot waves do not give rise to double-slit interference

#127

Post by abdullahkhalids »

soveran wrote: post #121
abdullahkhalids wrote: post #29

Earlier quoted context omitted.

Surprisingly, physicists are very much aware of the field nature of all "entities" in the world, having invented QFT themselves. Even more surprisingly, popular journalistic explanations simplify things considerably, making it seem that the thoughts of physicists are much less refined than they really are. To complete the trifecta of surprises, in the refined thought process of us physicists, using QFT, many problems…

Did you read the paper I linked to?

I did not read the whole thing, but I skimmed it. Its not a new-results type of paper. It is just collecting the works of other people and being careful about the language used. I have grappled with some of these issues/formalism/language in my own research as have many other physicists over the decades. The purpose of this paper is to argue that "Textbooks need to reflect that fields, not particles, form our most fundamental description of nature. This can be done easily, not by trying to teach the formalism of QFT in introductory courses, but rather by talking about fields, explaining that there are no particles but only particle - like phenomena caused by field quantization."

Notice that he is talking about teaching/talking/explaining. It is a for-teachers paper, not a for-researchers-working at-the-cutting-edge-of-fundamental-physics paper. And its nothing new. I taught an introductory level course on quantum mechanics recently and I refused to use the words "particle" or "wave" at any point in the course because I think they are confusing. I talked instead in terms of wavefunctions which is just an easier word for fields - at least as far as undergraduates are concerned.

Re: Oil droplets guided by pilot waves do not give rise to double-slit interference

#128

Post by jabl »

abdullahkhalids wrote: post #127
soveran wrote: post #121

Earlier quoted context omitted.

Did you read the paper I linked to?

I did not read the whole thing, but I skimmed it. Its not a new-results type of paper. It is just collecting the works of other people and being careful about the language used. I have grappled with some of these issues/formalism/language in my own research as have many other physicists over the decades. The purpose of this paper is to argue that "Textbooks need to reflect that fields, not particles, form our most fu…

This.

I did condensed matter Physics, where QFT isn't that essential, but from the QFT I did study the "it's all fields" way of looking at it came out quite naturally (well, how natural something as profoundly weird as QM can be, can be discussed..). So I fail to see how this can be considered particularly controversial.

I mean, if you want something controversial and non-mainstream, take the subject of this article, pilot wave theory.

PS: Do you have suggestions on a good introductory QM study materials (textbooks, online stuff,...) that emphasize the fields viewpoint?

Re: Oil droplets guided by pilot waves do not give rise to double-slit interference

#129

Post by lmm »

naasking wrote: post #98
lmm wrote: post #90

Earlier quoted context omitted.

I see many-worlds as a strict subset of pilot wave theory, since the pilot waves behave in exactly the same way as a many-worlds wavefunction. Adding a layer of particles-guided-by-the-waves on top of that is an extra complication that can only be justified (if at all) in terms of the intuitive appeal of their resemblance to macroscopic physics. (There's an argument of avoiding nonlocality/spooky-action-at-a-distance…

> Adding a layer of particles-guided-by-the-waves on top of that is an extra complication that can only be justified (if at all) in terms of the intuitive appeal of their resemblance to macroscopic physics. This "Bohmian mechanics is Many-Worlds in disguise" is simply false [1]. The axiomatic basis is completely different, and this is apparent because with Bohmian mechanics you can easily derive the Born rule, and as…

> This "Bohmian mechanics is Many-Worlds in disguise" is simply false [1].

Saying "clearly" a lot does not convince me, and seems to be all that paper does.

> The axiomatic basis is completely different, and this is apparent because with Bohmian mechanics you can easily derive the Born rule, and as a result, it also makes a new prediction that isn't allowed in typical QM, quantum non-equilibrium [2].

You've contradicted yourself: a quantum non-equilibrium condition would be one that did not follow the Born rule. Excluding quantum non-equilibrium requires an additional rule and looks to be much the same problem as deriving the Born rule under MWI. Were quantum non-equilibrium to be observed, that would be major evidence that our current understanding of QM is wrong; however, by the same token, our non-observation of it must count as evidence against a theory that predicts it.

Re: Oil droplets guided by pilot waves do not give rise to double-slit interference

#130

Post by effie »

whatshisface wrote: post #119
effie wrote: post #112

Earlier quoted context omitted.

> if you can actually do something paradoxical, like killing your grandfather. ... before certain crucial event in his life, you mean, I assume. How exactly does having a superluminal telephone imply I could change history? Changing history is the paradoxical part - don't assume it can happen.

Here is an article that goes in to the detail[0]. In so many words, you can use the superluminal telephone to transmit information to your own past. In essence, there is a certain amount of freedom in the simultaneity of events that is well-known to exist (having been experimentally verified). You can abuse it to create time paradoxes if and only if you can send messages faster than light - without FTL it is a curios…

Thanks for the link. See also the comments below the essay which give some valid criticisms.
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