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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

#71

Post by uryga »

perl4ever wrote: post #19
dumbfoundded wrote: post #16

Earlier quoted context omitted.

It's not a paradox if you put it in less confusing language. There are 4 possibilities: GG GB BG BB GG is impossible so you have GB, BG, & BB. One of them is a B, what's the other. Well that's clearly 2 / 3 G. The other one situation is completely. It's basically just the chance of a child being a girl.

But are those ordered pairs or sets of two items each?

I think of them as ordered pairs, but would it change anything if they were sets? Order doesn't matter in this question.

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

#72

Post by snarfy »

I don't understand why non-locality is a problem. Fields are non-local. If particles are point-like, fields are volume-like and permeate all of space. Problems like spooky action at a distance aren't really problems if there is no distance from the field's point of view.

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

#73

Post by naasking »

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

These have been largely ruled out via no-go theorems [1].

[1] https://en.wikipedia.org/wiki/PBR_theorem

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

#74

Post by Svoka »

Lerc wrote: post #6

So, am I right in thinking that we have. 1. Theory X hypothesizes Q 2. Phenomenon Y models theory X 3. Phenomenon Y does not demonstrate Q Surely there would be an insurmountable burden of proof on 2. Similarity does not mean identical. For any Y claiming to be the same as X, why can't it be rebutted with a "No it isn't" Proving that they are the same would be a different thing altogether but if as the article sugges…

only benefit of "Pilot Waves" are that they're intuitive and "humane". This hypothesis doesn't make any falsifiable predictions so far, only has lots and lots of very complex math.

It is mostly popular among people who want their physics to be visual and understandable to our scale intuition.

With this it basically drops only thing which made it attractive.

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

#75

Post by naasking »

whatshisface wrote: post #56
m12k wrote: post #53

I'm a bit sad that they couldn't reproduce the double slit interference pattern. I'm still holding out hope that we'll eventually develop a model of reality where the apparent indeterminism of quantum mechanics can be explained by currently unobservable interactions in higher dimensional space (such as the space described here: https://www.quantamagazine.org/physicists-discover-geometry-... )

What you're describing has been desired by many (including Einstein). However, John Bell more or less proved it impossible[0] in a landmark, sweepingly general result. He would have won a Nobel for it if he had lived long enough. On the other hand, if you are willing to accept superluminal messages and also unobservable mechanics, there is always the pilot wave interpretation[1]. The fluid analogy is disappointing to…

> On the other hand, if you are willing to accept superluminal messages and also unobservable mechanics, there is always the pilot wave interpretation[1]

All quantum interpretations have superluminal characteristics, but that's not the same as superluminal messaging/signaling.

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

#76

Post by mileszim »

whatshisface wrote: post #59
stupidcar wrote: post #50

Earlier quoted context omitted.

It matters because the theory in this case wasn’t that both light and tennis balls behave like a particle. It was that light behaves like a tennis ball. As such, demonstrating that tennis balls succeed or fail to display certain light-like behavior is certainly an important result. So, the most controversial aspect of pilot wave theory is the idea that a classical system can reproduce some phenomena considered only t…

One excercise that is fun to do: reduce the Schrodinger equation by splitting the real and complex parts, the figure out how to build a damped spring system that can support the wave. My interpretation of quantum mechanics is that everything is springs and dashpots in the end.

This is great, I think I'm going to explain it using your method from now on.

Edit: I love that there's a segment of people in the QM community approaching these "very serious" thought experiments like Schrodinger's Cat (as the classic example), instead using absurdism to produce equivalent but blatantly ridiculous results. Like the Surrealist reactionary art movement but with the often insane results QM produces. Sometimes I think string theorists need a group kind of like this too.

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

#77

Post by naasking »

lmm wrote: post #65
Lerc wrote: post #6

So, am I right in thinking that we have. 1. Theory X hypothesizes Q 2. Phenomenon Y models theory X 3. Phenomenon Y does not demonstrate Q Surely there would be an insurmountable burden of proof on 2. Similarity does not mean identical. For any Y claiming to be the same as X, why can't it be rebutted with a "No it isn't" Proving that they are the same would be a different thing altogether but if as the article sugges…

The whole value of pilot wave theory was that it was an interpretation of QM in terms of things that behaved like ordinary macroscopic particles and waves. Given that ordinary particles and waves don't actually behave like that, there's absolutely no reason to prefer pilot wave theory over simpler, more direct interpretations of QM.

I think your whole characterization of pilot theory's value and its relation to other interpretations is incorrect.

Firstly, it's primary value is that it's an ontological interpretation, meaning it preserves realism where most other interpretations sacrifice realism. The motion of its beables has nothing to do with this.

Secondly, pilot wave theory still requires the fewest number of assumptions, roughly on par with Many-Worlds, which means it's axiomatically simpler than other interpretations.

Whatever you mean by "simpler", its not a form of simplicity that actually matters when gauging plausibility of a theory.

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

#78

Post by zazen »

perl4ever wrote: post #51
reitanqild wrote: post #47

Earlier quoted context omitted.

I guess this is one of a few place to answer mu. One of the twins is still considered to be born first and therefore older :-)

I wrote a program and successfully got the right answers experimentally for each case, so I'm not doubting the answers, but I don't buy the explanation. While you may argue that one twin is always born first, this is an idealized mathematical problem, so it can't depend on particular details of physical reality in that way. There is nothing logically preventing them from being the same age, so it can't be pivotal to…

So, you don't actually have to regard BG and GB as separate cases if you don't want to.

People like to write the outcome space as ordered pairs BB, BG, GB, GG (ordered by age or whatever else), because this has the advantage that all four outcomes are equiprobable, so you can calculate probabilities just by counting.

If you prefer to regard the outcome space as unordered pairs {B,B}, {B,G}, {G,G} this is absolutely fine: you just have to bear in mind that the prior probability of {B,G} is 1/2, whereas it's 1/4 for the other pairs, so a tiny bit more calculation might be required.

P({B,G}| not {G, G}) = P({B,G})/(P{B,B} + P{B,G}) = (1/2)/((1/2) + (1/4)) = 2/3 as with the other method.

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

#79

Post by [deleted] »

whatshisface wrote: post #59
stupidcar wrote: post #50

Earlier quoted context omitted.

It matters because the theory in this case wasn’t that both light and tennis balls behave like a particle. It was that light behaves like a tennis ball. As such, demonstrating that tennis balls succeed or fail to display certain light-like behavior is certainly an important result. So, the most controversial aspect of pilot wave theory is the idea that a classical system can reproduce some phenomena considered only t…

One excercise that is fun to do: reduce the Schrodinger equation by splitting the real and complex parts, the figure out how to build a damped spring system that can support the wave. My interpretation of quantum mechanics is that everything is springs and dashpots in the end.

[deleted]

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

#80

Post by naasking »

dumbfoundded wrote: post #10
Lerc wrote: post #6

So, am I right in thinking that we have. 1. Theory X hypothesizes Q 2. Phenomenon Y models theory X 3. Phenomenon Y does not demonstrate Q Surely there would be an insurmountable burden of proof on 2. Similarity does not mean identical. For any Y claiming to be the same as X, why can't it be rebutted with a "No it isn't" Proving that they are the same would be a different thing altogether but if as the article sugges…

That's a fair observation. Though, I think the thought experiment to about the distance between the two slits as irrelevant to QM more concretely disproves the pilot wave theory. Most physicists when asked about QM will just say that this is a useful model to predict the outcomes of experiments. In fact the most successful model, ever. The magic that happens in the middle is currently untestable and thus uninterestin…

> Though, I think the thought experiment to about the distance between the two slits as irrelevant to QM more concretely disproves the pilot wave theory.

This sort of experiment does not disprove pilot waves.

> Science works in a very simple way. We have evidence about how the universe works. We make models to explain that evidence. The models also make predictions about new evidence that we would expect to see. New evidence appears and either confirms or limits the domain of the model

This is a very anemic view of the scientific process. Scientific theories have predictive and explanatory power. You described the process covering only the former, but the latter is critical for advancing theory.

For instance, without Bohmian mechanics John Bell probably would never have developed Bell's Theorem and all the subsequent no-go theorems which have dramatically improved our understanding of quantum foundations.

Theories that provide a mental framework for thinking about problems guide you in devising new experiments. Theories with no explanatory power provide no meaningful framework within which to devise new experiments.

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