On Fri, Mar 21, 2014 at 3:00 PM, John Clark <johnkcl...@gmail.com> 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 everything-list+unsubscr...@googlegroups.com. To post to this group, send email to everything-list@googlegroups.com. Visit this group at http://groups.google.com/group/everything-list. For more options, visit https://groups.google.com/d/optout.
