Reply To: Retrocausal Bohm Model

[Aurelien Drezet]

Dear Rod, I realized That I didnt make justice to all you comments concerning my questions. Here a small list of points:
–You wrote :’If you’re puzzled about something with the final psi, ask yourself if you would still be puzzled if you were just talking about the initial psi instead.’
This is an important point it reminds me the double-standard objection of Huw Price. But what is puzzling for me is not that you are using the final psi or the initial psi but that you are using both. I am not convinced that this will not introduce some contradictions if you want to prove the equivalence with the usual Bohm formalism: that is with QM it self. Actually, I have the same problem with the two-time formalism of Aharonov et al..

— You wrote: ‘So the final boundary condition is fixed in an analogous way to the state preparation of an initial psi. ‘
This is also mysterious. The final state should equivalent to what is given by orthodox QM and represents therefore the evoving state of Psi in. How can we be sure that we dont introduce too many degrees of freedom in the model? Feynman used a trick like yours in QED but we can show that this is formally equivalent to usual Quantul Field with only one initial boundary condition. The equivalence is not obvious in your model.

— You wrote: ‘Unlike classical physics, there is no doubt that two boundary conditions are needed in this picture, since otherwise Bell’s nonlocality could not be explained in a Lorentz invariant fashion via a spacetime zigzag. ‘
That’s not obvious. Even if a time symmetric theory is better for explaining Bell results and nonlocality (on this I agree completely) this is not a proof that more usual way will not work. Again, this is the story of Feynman theory. May be the usual wave function contains already retrocausality like in some model by Nikolic (which I dont want to comment here since I do not agree with the details).
Any way your approach is one of most interesting presented to solve the difficulties of covariance. This is much better that the usual preferred foliation used by Durr et al.