A electron can exist in everywhere ?

[bhobba]

If you read the papers linked above, Leifer argues that PBR rules out an option favoured by Einstein:

I have read what Leifer says and think he is correct but is drawing the wrong conclusion - or rather just because it is sick does not mean the theory (under that interpretation) still can not be used.

The PBR theorem only applies to standard QM - not to some hypothetical theory that QM may be the approximation of like classical thermodynamics is the approximation of quantum thermodynamics. This was Einsteins belief - QM was not incorrect - just incomplete and he would have thought the PBR theorem is simply a symptom of that incompleteness. Classical thermodynamics has problems such as the black-body radiation problem quantum theory fixes up. There are similar issues with Electrodynamics such as the infinite self energy of the field and acasual runaway solutions in some circumstances. But again it is not an issue because it is only an approximation to QED that resolves the problems (but of course has others) - in virtually all practical situations classical Electrodynamics is applied to no problems arise - but to be sure it is in fact a sick theory. Einstein would be smiling merrily and looking over to Bohr who really couldn't care less because like me he thought the state, although fundamental, was simply knowledge about the system and not something real and physical.

In fact one version of the Ensemble interpretation accepts Einsteins take and that when you make an observation it selects a pre existing outcome despite Kochen-Sprecker. It invokes some as yet unknown theory to resolve it. Conceptually actually a very neat solution. It has but one problem - what is this theory it is an approximation to - damn that pesky detail.

Funny how nothing really has changed on the QM interpretation front - each side simply retreats to their impregnable positions - hmmm - I seem to recall posting that before.

Thanks
Bill

 

[bohm2]

I think Bohr would have been happier with the PBR theorem than Einstein. The reason, being that PBR leaves anti-realist approaches unscathed whereas it eliminates certain ontic models where ψ is epistemic/probabilistic. Not that there are any theorems that are likely to eliminate anti-realistic approaches. Having said that, there are other models that are also not affected by PBR or Bell's: superdeterministic ones.

 

[bhobba]

Yea Bohr may have liked PBR.

But really its this 'realist' view of the world that is the issue - for some of us its just so deeply ingrained its hard to shake and why I think there will always be disagreement.

Early on I was in the realist camp but after a while its baggage became too much and I jumped ship - long before PBR BTW.

Thanks
Bill