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There exists a classical model of the photon after all

lightbluetouchpaper.org

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

#11

Post by Strilanc »

Scott Aaronson has commented negatively on a previous paper by the same authors [1]. I don't know if similar issues apply to this one:

> [...] the paper advances the prediction that quantum computation will never be possible with more than 3 or 4 qubits. [...] I wonder: before uploading their paper, did the authors check whether their prediction was, y’know, already falsified? How do they reconcile their proposal with (for example) the 8-qubit entanglement observed by Haffner et al. with trapped ions [...]

(Note: that's a critique of the previous paper, not the linked one. Although the linked post mentions quantum computers not working, the linked paper does not touch the subjet.)

1: http://www.scottaaronson.com/blog/?p=1255

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

#12

Post by btilly »

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 postulate sounds like it enables non-local behavior (which it has to to match current versions of the Bell test) so it is unable to help resolve the issue of reconciling GM with QM.

So this does rather less than they claim. Assuming that their claimed result is correct.

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

#13

Post by maaku »

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".

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

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

#14

Post by rayiner »

jerf wrote: post #6
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…

To really, really get it? The standard electromagnetism semester and a QM semester, both "for majors" (not the simplified general version), and something else for the "inviscid compressible fluid" (fluid dynamics, I assume, this might require some stuff that won't come up until semester 2, not sure), and a factor difficult to express in terms of semesters that you are not merely aping the mathematical results you are…

An aerospace major who took a QM elective, or a physics major who took a couple of aerodynamics electives, would probably cover the necessary material by the end of year 2 of an undergraduate program. If you've got a solid, intuitive grasp of calculus and differential equations, you could probably learn enough from lecture notes to understand this in a few weeks. This is the most accessible physics paper that you'll ever see make the news.

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

#15

Post by clavalle »

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 and trumps classical mechanics.

It call all be understood as movement of 'particles' of light (photons) on an underlying wave.

http://en.wikipedia.org/wiki/Magnetic_flux_quantum

http://simple.wikipedia.org/wiki/Magnetic_flux

http://en.wikipedia.org/wiki/Flux_tube

http://en.wikipedia.org/wiki/Quantum_vortex

http://en.wikipedia.org/wiki/Wave_packet

http://en.wikipedia.org/wiki/Maxwell%27s_equations

http://en.wikipedia.org/wiki/Differential_equation

http://en.wikipedia.org/wiki/Polarization_%28waves%29

http://en.wikipedia.org/wiki/Bell_test_experiments

http://en.wikipedia.org/wiki/Fluid_dynamics

http://en.wikipedia.org/wiki/Pilot_wave

http://en.wikipedia.org/wiki/De_Broglie%E2%80%93Bohm_theory

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

#16

Post by fixermark »

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)?

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

#17

Post by btilly »

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)?

I don't know and don't keep track. I lost interest after realizing that it can be made compatible with any possible observation.

I'm personally a fan of the Everett interpretation. Also called the many worlds. Which is what you get if you assume that quantum mechanics applies to the observer. Then the act of observation throws the observer into a superposition of possible states where different things were observed. And those states cannot meaningfully interact later for thermodynamic reasons.

Unless someone comes up with good reason to believe that quantum mechanics does not describe humans, I see no reason not to accept it. And if quantum mechanics is replaced by something different, to the extent that quantum mechanics is an accurate description of us, that interpretation remains correct.

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

#18

Post by sampo »

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 introductory QM book that I know of. If you managed to read Electrodynamics, you should by now know enough calculus for this book, too. But you also need to know about complex numbers here.

The "inviscid compressible fluid" is about fluid mechanics. I don't know any splendid textbook on that.

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

#19

Post by UhUhUhUh »

maaku wrote: post #13
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".

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

Really? Did Einstein have empirical proof of his ideas?

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

#20

Post by sp332 »

fdej wrote: post #3
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…

You should be able to understand everything in that sentence if you have taken a typical undergraduate curriculum in physics including quantum mechanics and electromagnetism. Though it depends on what you mean by "understand". It should be clear what "quantised magnetic flux" is roughly about, but I have no idea what constitutes the "modern knowledge of quantised magnetic flux" in this context.

That doesn't help with the first part, about a phase vortex in compressible inviscous liquids.
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