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Fluid Tests Hint at Concrete Quantum Reality

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Re: Fluid Tests Hint at Concrete Quantum Reality

#81

Post by tim333 »

Estragon wrote: post #6

Are there any experiments where the pilot wave theory and the Copenhagen interpretation predict different results?

It depends a bit how you define things. The Copenhagen interpretation has a collapsing wave function doing so in a way where we can't observe it collapse and the pilot wave theory has pilot waves all over the place that have no effect other than guiding the particle in question then effectively disappearing when not needed. If either the collapses or pilot waves were real things I would kind of expect them to be observable in some way, but in both interpretations they are not observable, which leads me to suspect they are not real things and will go the way of the "luminiferous aether".

Re: Fluid Tests Hint at Concrete Quantum Reality

#82

Post by acqq »

scott_s wrote: post #71
acqq wrote: post #70

Earlier quoted context omitted.

Thanks Scott. I understand that phlogiston thrived until real honest scientific experiments disproved it. Thanks to which "interpretation" before that point? Can't we call it "shut up, experiment and calculate"? Or, simpler, "do the science."

There was none, that I'm aware of. It was a long, drawn out affair over more than a century, as far as I know. If you're looking for a direct analog to the situation with interpreting quantum mechanics, then I'm afraid you won't find it. The analogy I draw from it is not direct, but merely: scientists unavoidably think of their work in certain ways that are themselves not tested. This thinking influences their work.…

Just by looking at the Wikipedia entry, it appears that Kuhn's book is more philosophical than the carefully researched history of science. How do you see it?

Re: Fluid Tests Hint at Concrete Quantum Reality

#83

Post by deutronium »

spacehome wrote: post #18

Yes! But the best theory is not Copenhagen or Pilot Wave. Eliezer Yudkowski has a brilliant treatise on the Many Worlds interpretation here: http://lesswrong.com/lw/r5/the_quantum_physics_sequence/ that really should be required reading for anyone that wants to talk intelligently on the subject. Edit: seriously, don't even bother reading the article. It (like most science journalism) is garbage. Take the time to work…

And why should we read Yudkowski instead, rather than other physicists on this matter, as far as I know he's not in a position of authority in this area.

Re: Fluid Tests Hint at Concrete Quantum Reality

#85

Post by jostylr »

tim333 wrote: post #81
Estragon wrote: post #6

Are there any experiments where the pilot wave theory and the Copenhagen interpretation predict different results?

It depends a bit how you define things. The Copenhagen interpretation has a collapsing wave function doing so in a way where we can't observe it collapse and the pilot wave theory has pilot waves all over the place that have no effect other than guiding the particle in question then effectively disappearing when not needed. If either the collapses or pilot waves were real things I would kind of expect them to be obse…

Funny that you say that since the particles are pretty much all we do observe. You never "see" the wave function, but you do see where stuff is.

To be charitable to Copenhagen, we would say that we do see the results of collapse. The main problem with the collapse is that is simply not well-specified by the theory.

Re: Fluid Tests Hint at Concrete Quantum Reality

#86

Post by jostylr »

jostylr wrote: post #58
Estragon wrote: post #6

Are there any experiments where the pilot wave theory and the Copenhagen interpretation predict different results?

In pilot wave theory, one can deduce the standard quantum formalism. Operators, collapse, and all the rest just pop right out. So no, there is no experiment that can tell the difference. It is possible that pilot wave theory has predictions that the standard formalism is silent on. However, something that is inspired by pilot wave theory can be easily co-opted by standard approaches, e.g., Bell's theorem.

As an example, it is very easy to place pilot wave theory on manifolds as these are just differential equations. For the standard theory, it is not at all clear what the main operators ought to be such as momentum. Position, yes, but not other things.

Of course, once one has pilot wave theory on it, then whatever needs to be deduced can be and then given to the standard theory.

Re: Fluid Tests Hint at Concrete Quantum Reality

#87

Post by spacehome »

danbruc wrote: post #63
acqq wrote: post #55

Earlier quoted context omitted.

On that level I don't have any problem with "many worlds" as it can be seen just a one more extrapolation of "we're not in the designed special position" principle: first we're not the center around which the planets circle, then our Sun also isn't the center of our set of stars, then our set of stars is one of many other galaxies... if our physical universe is just a lucky variant of other possible (and mostly unint…

But there is an important difference - you can observe the other stuff in our universe and therefore know that we are not (exceptionally) special in our universe. Other universes are usually per definition completely outside of our reach, as hard to grab as a god or Russell's teapot.

Well, they're not completely outside our reach. Interference between our worlds and nearby ones is very testable, and the reason the theory exists.

Re: Fluid Tests Hint at Concrete Quantum Reality

#88

Post by spacehome »

deutronium wrote: post #83
spacehome wrote: post #18

Yes! But the best theory is not Copenhagen or Pilot Wave. Eliezer Yudkowski has a brilliant treatise on the Many Worlds interpretation here: http://lesswrong.com/lw/r5/the_quantum_physics_sequence/ that really should be required reading for anyone that wants to talk intelligently on the subject. Edit: seriously, don't even bother reading the article. It (like most science journalism) is garbage. Take the time to work…

And why should we read Yudkowski instead, rather than other physicists on this matter, as far as I know he's not in a position of authority in this area.

I would never say instead of. Read whomever you like; read them all. Though, I would suggest that anyone who still takes Copenhagen seriously really needs to digest that sequence.

Eliezer is a smart guy with great insights into how to think about questions. His "position of authority" is that he writes in a way that's clear and conveys meaningful novel insights. If you think that only Ph.D.s have insights worth reading you're missing out. There's nothing "new" or "publishable" in the sequence, but Eliezer collates a lot of good ideas and presents them well.

For what it's worth, I personally feel like I've learned a lot from reading him. I was just trying to share it in the hopes that someone else on HN may find him as insightful as I do, and the quantum physics sequence is one of his better works. It was just a friendly pointer. If you're not interested, disregard.

Re: Fluid Tests Hint at Concrete Quantum Reality

#89

Post by scott_s »

acqq wrote: post #82
scott_s wrote: post #71

Earlier quoted context omitted.

There was none, that I'm aware of. It was a long, drawn out affair over more than a century, as far as I know. If you're looking for a direct analog to the situation with interpreting quantum mechanics, then I'm afraid you won't find it. The analogy I draw from it is not direct, but merely: scientists unavoidably think of their work in certain ways that are themselves not tested. This thinking influences their work.…

Just by looking at the Wikipedia entry, it appears that Kuhn's book is more philosophical than the carefully researched history of science. How do you see it?

Mostly philosophical. It's given me ways to think about how science is done in practice.
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