Brent Meeker wrote:


>  > Bruno:
>  > I disagree: in Bohm QM there *are* other branches. This
>>  follows from the fact that there is no collapse. The SWE is
>>  obeyed. Bohm just add a potential which forces a (mysterious)
>>  set of particles with very special initial conditions to
>>  follow one branch of the universal superpositions. But to
>>  explain the interference Bohm accepts the existence of the
>>  other branches even if they are lacking particles. And to
>>  explain the behavior of a quantum computer even in just "our"
>>  branch, a Bohmian must accept that the computers of the other
>>  branches are able to make reasoning like any AI, even if they
>>  lacks particles. So Bohm is forced to abandon comp, as he
>>  does. (This illustrates also that existence of particles is
>>  hardly necessary with comp).


Brent:
>There need not be any collapse to explained the point-like
>interactions because there interactions are between particles.
>  The particles move in accordance with a potential which
>exhibits interference.  This potential is determined by all
>the particles in the universe.  The probabisltic aspect arises
>from the particles having a certain random position
>distribution.  The theory assumes that the interaction of the
>particles and their potential has put them into equilibrium
>distribution.  The probabilistic aspect comes form our lack of
>knowledge of this distribution.


Bruno:
I agree. I did not mention collapse.


Brent:
>See  [Shelly Goldstein:]
>
>http://www.math.rutgers.edu/~oldstein/papers/qts/node4.html
>
>Since the theory is completely deterministic, there is only one
>world.


Bruno:
Not with comp. How could we know we are in the branch (which all
exist because of SWE and absence of collapse) possessing the
particles?

BTW Everett MW is also deterministic. Randomness is a consequence
of us not knowing in which universe we are. It is simple comp
first person randomness.

Also the way the wave function choreographs (to speak like
Shelly Goldstein  you refer above) the particles, is
non local, while with MW we have a local theory.

But the main question is: how could we know we are in the branch
possessing the "real" particles?


Bruno






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