There exists a classical model of the photon after all • Hacker News Board

Re: There exists a classical model of the photon after all

#31

Post by ars » Mon, Feb 23, 2015, 8:09 PM UTC

btilly wrote: post #12

They claim to have found a classical system that reproduces quantum mechanical effects. But if they manage to extend it to many particles, interacting, they will find that they have just come up with another interpretation of QM which is experimentally indistinguishable from the rest. And it wouldn't even be the first one. (Bohm's hidden variable theory has precedence.) Furthermore the "incompressible fluid" they pos…

> Furthermore the "incompressible fluid" they postulate sounds like it enables non-local behavior

It says compressible not incompressible.

Re: There exists a classical model of the photon after all

#32

Post by sp332 » Mon, Feb 23, 2015, 8:09 PM UTC

UhUhUhUh wrote: post #19

maaku wrote: post #13

Earlier quoted context omitted.

Reasoning from intuition has a terrible track record, I'm afraid.

Really? Did Einstein have empirical proof of his ideas?

Einstein started with large amounts of empirical data and created models that explained them.

Re: There exists a classical model of the photon after all

#33

Post by troymc » Mon, Feb 23, 2015, 8:12 PM UTC

btilly wrote: post #12

They claim to have found a classical system that reproduces quantum mechanical effects. But if they manage to extend it to many particles, interacting, they will find that they have just come up with another interpretation of QM which is experimentally indistinguishable from the rest. And it wouldn't even be the first one. (Bohm's hidden variable theory has precedence.) Furthermore the "incompressible fluid" they pos…

Models like theirs predate Bohm by a long shot. From the introductory paragraph of the paper:

"In 1746 Euler modelled light as waves in a frictionless compressible fluid; a century later in 1846, Faraday modelled it as vibrations in ‘lines of force’ … Fifteen years later Maxwell combined these approaches, proposing that a magnetic line of force is a ‘molecular vortex’…"

They basically updated Maxwell's model. From their conclusion:

"We brought Maxwell’s 1861 model of a magnetic line of force up to date using modern knowledge of polarised waves and of experiments on quantised magnetic flux. Our model obeys the equations for Euler’s fluid and supports light-like solutions which are polarised, absorbed discretely, consistent with the Bell tests, and obey Maxwell’s equations to first order."

What's nice is that their model is classical. Even if it "just" makes exactly the same predictions as other models, it's nice to have a model where physical intuition can be brought to bear.

Re: There exists a classical model of the photon after all

#34

Post by rpcope1 » Mon, Feb 23, 2015, 8:15 PM UTC

UhUhUhUh wrote: post #19

maaku wrote: post #13

Earlier quoted context omitted.

Reasoning from intuition has a terrible track record, I'm afraid.

Really? Did Einstein have empirical proof of his ideas?

Special relativity still holds where it is applicable, and general relativity has yet to be refuted, and has been verified in interesting ways (gravitational lensing of Mercury with regards to the precession of it's perihelion for example). Einstein's other ideas about phenomenon such as the photoelectric effect and Brownian motion have been long since verified, so I would say, especially in comparison to some of his contemporaries, his theories oh withstood the test of time very well.

Re: There exists a classical model of the photon after all

#35

Post by itistoday2 » Mon, Feb 23, 2015, 8:16 PM UTC

clavalle wrote: post #15

cevn wrote: post #2

"Updating this with modern knowledge of quantised magnetic flux, we show that if you model a flux tube as a phase vortex in an inviscid compressible fluid, then wavepackets sent down this vortex obey Maxwell’s equations to first order; that they can have linear or circular polarisation; and that the correlation measured between the polarisation of two cogenerated wavepackets is exactly the same as is predicted by qua…

It can take a bit of unpacking, but someone with some sort of college level physics and mathematics background can use Wikipedia to get a basic understanding of what they are talking about. They are basically saying that the quantum mechanical 'strangeness' of light can be explained with classical, deterministic, physics. It is not necessary to have a separation in which quantum mechanics predominates at one level an…

Pilot wave theory has been known for decades. So can someone explain how whatever they're talking about is different/new?

Re: There exists a classical model of the photon after all

#36

Post by projectileboy » Mon, Feb 23, 2015, 8:17 PM UTC

sampo wrote: post #18

cevn wrote: post #2

"Updating this with modern knowledge of quantised magnetic flux, we show that if you model a flux tube as a phase vortex in an inviscid compressible fluid, then wavepackets sent down this vortex obey Maxwell’s equations to first order; that they can have linear or circular polarisation; and that the correlation measured between the polarisation of two cogenerated wavepackets is exactly the same as is predicted by qua…

> How long would I have to study physics to be able to understand everything in this sentence? Just start reading David J. Griffiths: Introduction to Electrodynamics . A very well written textbook. The problem might be, if you don't know vector calculus, you might not be able to read this book, so you need to learn some vector calculus, too. Then start reading Introduction to Quantum Mechanics by Griffiths, too. Best…

Wow, so nice to hear props for Griffiths' textbooks. I think he's by far the best physics textbook author.

Re: There exists a classical model of the photon after all

#37

Post by bkcooper » Mon, Feb 23, 2015, 8:18 PM UTC

fixermark wrote: post #16

btilly wrote: post #12

They claim to have found a classical system that reproduces quantum mechanical effects. But if they manage to extend it to many particles, interacting, they will find that they have just come up with another interpretation of QM which is experimentally indistinguishable from the rest. And it wouldn't even be the first one. (Bohm's hidden variable theory has precedence.) Furthermore the "incompressible fluid" they pos…

What's the current status of Bohm's hidden variable theory? Does it stand up in light of the Bell test (I was under the impression that the Bell results suggest an arbitrary number of hidden variables would be necessary)?

What's the current status of Bohm's hidden variable theory? Does it stand up in light of the Bell test?

Yes. Bell's theorem doesn't forbid hidden variable theories (in fact, he has a publication preceding his famous result explicitly demonstrating a hidden variable theory that could reproduce QM measurements on a two-level system), just local hidden variable theories. In his collected papers, Bell often remarks that he feels Bohm's interpretation should be more widely studied.

It's a good question why it's not. My understanding, though I'm not well versed in the subject, is that there are some pretty severe shortcomings to it, particularly when you start considering systems with many particles. I've read some of Bohm's writings to try to understand it and as far as I got I found it pretty underwhelming; it seemed more like a bookkeeping trick than any sort of real insight.

Re: There exists a classical model of the photon after all

#38

Post by taybin » Mon, Feb 23, 2015, 8:21 PM UTC

"if the fundamental particles are just quasiparticles in a superfluid quantum vacuum"

well obviously.

Re: There exists a classical model of the photon after all

#39

Post by mikeash » Mon, Feb 23, 2015, 8:43 PM UTC

UhUhUhUh wrote: post #19

maaku wrote: post #13

Earlier quoted context omitted.

Reasoning from intuition has a terrible track record, I'm afraid.

Really? Did Einstein have empirical proof of his ideas?

Einstein won his Nobel Prize for explaining the photoelectric effect, a measured phenomenon that didn't have an adequate explanation.

His work on brownian motion showed that the observations of the movements of small particles can be explained by the nature of fluids as being made up of small particles (i.e. molecules).

Special relativity is what you get when you combine the seemingly contradictory observed phenomena that there's no such thing as absolute motion and that the speed of light is a constant to all observers.

General relativity combines that with the observed phenomenon of gravity.

While I don't know whether these constitute "proof," Einstein certainly had a lot of empirical support for his ideas, and they weren't anything like pure intuition.

Re: There exists a classical model of the photon after all

#40

Post by phkahler » Mon, Feb 23, 2015, 8:43 PM UTC

sp332 wrote: post #27

phkahler wrote: post #8

I hope this is as awesome as it sounds. It sums up everything I've been thinking about quantum physics, from "someone should look closer at Couders work" to "spooky action at a distance is BS" to "Quantum computers will never work - see spooky action".

Spooky action has been empirically demonstrated. https://arstechnica.com/science/2012/04/decision-to-entangle...

I call BS. If that's true, then Victor can not only send information across a distance, but back in time. Victor is changing the correlation of Alice and Bobs measurements after they have already been made. That's going to need serious verification for me to accept.