e-mail to David Deutsch February 28,2001
the mentioned publication is D.Deutsch,P.Hayden 
quant-ph/9906007, Proc.Roy.Soc. London A456,1759 (1999).

Dear Professor Deutsch,

I read with great interest your recent publication
"Information flow in entangled quantum systems".
Some years ago I became convinced the multiverse must exist when 
I realised - triggered by remarks in Everettīs thesis, and
without proving it - that 
only then EPR can be understood realistically with no
non-local elements.

I was then chagrined to find that ALL proponents 
of MWI with which I discussed the issue - except Frank Tipler, but
including Don Page -
told me a local description is impossible (to put it mildly :-)).
Frank told me about similar experiences.

Please allow me some questions:

- On the background of what I wrote above,
  does the conclusion of your paper that QM is local,
  really "go against the stream", or do I confuse something?

David Deutsch's answer from Aug 1,2001:
It goes against the stream. Or perhaps I should say, it diverts the stream!

A further question from Feb 28 was:

- I had to ask the last question because the exact physical nature of 
  "locally inaccessible information" in a system is not completely
  clear to me. In this connection the recent work of Luis and Sanchez-Soto
  (PRL 81,4031 (1998) and J.Opt.B 1,668 (1999)) might be interesting.
  They argue that in simple physical situations entanglement can understood
  as being caused by kicks to the quantum phase.
  In the latter reference and for the case of photons 
  they identify this quantum phase as the one known from 2nd quantisation
  in the number-phase uncertainty relation.
  In that case the kicks would seem to be of a local nature, in line
  with your findings.
  Is the "locally inaccessible information" encoded in relative quantum-phases
  between entangled systems?
  Phase differences are locally inaccessible without involving anything
  truly non-local, so it *sounds* reasonable, but does it make sense?

David Deutsch's answer from Aug 1,2001:
I'm not sure. I'll think about it.
'Relative phases' is terminology from the Schrodinger picture, but I think
the answer is yes.