On Fri, Mar 21, 2014 at 3:00 PM, John Clark <[email protected]> wrote:
> On 18 Mar 2014, at 22:33, LizR wrote: > > > Am I right in assuming that in a quantum mechanical universe you can >> trace the history backwards? >> > > Absolutely not because in Quantum mechanics 2 very different states can > evolve into the exact same state. > Not if you're just talking about the evolution of the quantum state vector according to the Schroedinger equation, which is totally deterministic. As I said to Liz, non-reversibility only appears if you assume the "collapse" of the wavefunction to a new quantum state on measurement is a real physical phenomenon distinct from normal wavefunction evolution, rather than an approximate description of something that happens due to decoherence (as would be true in the many-worlds interpretation where the universal state vector is all there is, and also in Bohm's hidden variables interpretation which is deterministic at all stages). Jesse -- You received this message because you are subscribed to the Google Groups "Everything List" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send email to [email protected]. Visit this group at http://groups.google.com/group/everything-list. For more options, visit https://groups.google.com/d/optout.
