Bohmian interpretaion and the special relativity

[feynmann]

If Bohmian interpretaion fails the special relativity, but how about Copenhagen interpretation?
Does Copenhagen interpretation fails the SR also? Per John Bell, any quantum theory must be non-local, so fails the SR

I believe that Bohmian interpretaion fails the special relativity analysis, because his pilot wave is required to travel faster than light.

 

[rjbeery]

"Pilot waves", if considered to be moving backwards in time from the absorber to the emitter, do not need to travel faster than light. In that respect, certain Absorber Theories do not seem to violate SR.

 

[Demystifier]

The Bohmian interpretation is non-local, but it does not (necessarily) fail special relativity. As recently demonstrated, it can be made completely relativistic-covariant:
http://xxx.lanl.gov/abs/0811.1905 [Int. J. Quantum Inf., in press]

 

[Demystifier]

Per John Bell, any quantum theory must be non-local, so fails the SR

Even John Bell himself noted that nonlocality does not necessarily imply the failure of SR.

 

[DrChinese]

Per John Bell, any quantum theory must be non-local, so fails the SR

Bell actually said that any hidden variable theory must be non-local. But there do not need to be hidden variables - that is merely one possibility.

 

[feynmann]

Bell actually said that any hidden variable theory must be non-local. But there do not need to be hidden variables - that is merely one possibility.

But entangled particles do seem to be connected in a way which is "non-local" and therefore somehow violating the speed of light c. This has nothing to do with hidden variable, so even "non-hidden variable" theory violates the speed of light and SR

 

[rjbeery]

Wait a minute, regardless of what Bell said, can someone explain to me how a retro-causal interpretation is non-local assuming that the backwards-in-time signal is traveling at a speed |v| <= c?

 

[DrChinese]

Wait a minute, regardless of what Bell said, can someone explain to me how a retro-causal interpretation is non-local assuming that the backwards-in-time signal is traveling at a speed |v| <= c?

I think it might make sense to instead explain how a retro-causal interpretation can emulate non-locality - specifically it can emulate the non-locality that is associated with wave function collapse.

The idea is that future states - at (widely) separated future spacetime points - can influence particle creation in the present. If you will, Alice & Bob's future measurement settings affect the photon pair being created now (this is simplifying because their settings affect the outcome in a somewhat indirect fashion). Since this information is available in the present - to the particles being created - there is no problem explaining the observed correlations.

The path of the future-to-past influence follows a traditional geodesic line in spacetime, with the traditional limit of c. Of course, that would essentially be -c. Additionally interesting to me is that the rest of the universe does have an influence on what happens here and now - just like in Bohmian/dBB theory. And it is almost a non-local influence. Most of these influences interfere destructively or otherwise will not establish the proper conditions to influence the present.

The above is not intended to be an exact description, as you can look at the references to see that. But it should give you a feel as to apparent non-locality can be explained by a time-symmetric formulation.

 

[rjbeery]

DrChinese: Thanks for the explanation; I concur with you that retro-causal interpretations qualify as local. I was hoping to hear the logic that claimed this was not the case (is Bell around??)