Loading ...
Sorry, an error occurred while loading the content.

Re: Is the quantum potential observable/uncertain?

Expand Messages
  • tkuntzle@umich.edu
    ... the ... This makes perfect sense. ... potential, ... or indeterminate ... field ... associated ... space ... Yes, this does help a lot. Thank you for
    Message 1 of 4 , Jan 1, 2001
    • 0 Attachment
      --- In bell_bohm@egroups.com, Eric Dennis <edennis@p...> wrote:
      > Welcome Tom...
      >
      >
      > Nope. No more or less unobservable than a classical potential. It
      > influences particles, and we can detect that influence by detecting
      the
      > particles (their positions/momentat/etc).

      This makes perfect sense.


      >
      > > (2) "hides" the uncertainty. In other words, the quantum
      potential,
      > > if it could be observed, would have quantities that would not be
      > > possible to measure with complete precision.
      >
      > No again. Nothing is inherently imprecise or ambiguous
      or "indeterminate"
      > in dBB. The only difference between the "quantum potential" and a
      > classical potential is that the former is not associated with any
      field
      > occupying physical space (x,y,z). If you want you can say it's
      associated
      > with the wavefunction as a "field" (not in the QFT sense), but the
      > wavefunction exists not in physical space but in the configuration
      space
      > of the entire system (e.g. for N particles, config space has 3N
      > dimensions).
      >
      > Hope that helps.
      >
      > --Eric

      Yes, this does help a lot. Thank you for taking the time to answer.
      So the only real problem with the Bohm/de Broglie interpretation is
      that the quantum potential is an entity that can move faster than the
      speed of light, and thus relativity is violated?

      I have also heard that the Bohm/de Broglie interpretation has not
      been extended to systems of more than one particle, but your previous
      answer seems to suggest that this is not the case. Am I correct in
      assuming that dBB has been extended to systems of more than one
      particle?

      Does dBB answer the paradoxical nature of correllated systems that
      consist of states with probabilities that cannot be constructed by
      linear combination of the individual states making up the correllated
      system? Does this convoluted question make any sense?!

      Tom
    • Eric Dennis
      ... Right. There are influences moving faster than light (FTL), described by the quantum potential, violating fundamental relativity. It should be emphasized
      Message 2 of 4 , Jan 1, 2001
      • 0 Attachment
        Tom wrote:

        > Yes, this does help a lot. Thank you for taking the time to answer.
        > So the only real problem with the Bohm/de Broglie interpretation is
        > that the quantum potential is an entity that can move faster than the
        > speed of light, and thus relativity is violated?

        Right. There are influences moving faster than light (FTL), described by
        the quantum potential, violating fundamental relativity. It should be
        emphasized that any theory reproducing the QM predictions (including
        standard QM itself) implies FTL influences, which is the point of Bell's
        Theorem.

        > I have also heard that the Bohm/de Broglie interpretation has not
        > been extended to systems of more than one particle, but your previous

        dBB does cover many particle systems--in fact, it's only here that the FTL
        influences occur. For many particle systems, the wavefunction and quantum
        potential are functions of _all_ the degrees of the freedom, which is what
        gives rise to the non-locality.

        > Does dBB answer the paradoxical nature of correllated systems that
        > consist of states with probabilities that cannot be constructed by
        > linear combination of the individual states making up the correllated
        > system? Does this convoluted question make any sense?!

        I think what you mean is correlated systems involving wavefunctions which
        are not factorizable into a _product_ of sub-system wavefunctions. Indeed
        it is precisely these "entangled" states which exhibit FTL influences in
        any version of QM, including dBB.

        You might also be getting at von Neuman's "refutation" of hidden variable
        theories--now understood to be invalid--which made a point about linear
        combinations of _operators_ and the linearity of their expectation values.

        Eric
      Your message has been successfully submitted and would be delivered to recipients shortly.