On Saturday, April 28, 2018 at 10:55:13 PM UTC, [email protected] wrote: > > > > On Saturday, April 28, 2018 at 9:33:58 PM UTC, Brent wrote: >> >> >> >> On 4/28/2018 9:39 AM, [email protected] wrote: >> > Is it a settled issue whether measurements in QM are strictly >> > irreversible, >> >> There are interactions that, if you did not arrange that they be erased, >> would constitute measurements. Whether you say they were measurements >> and then got erased or they are not measurments because they didn't >> produce an irreversible record is a phlosophical or semantic question. >> >> > that is irreversible in principle, or just statistically irreversible, >> > that is, reversible but with infinitesimal probability? TIA, >> >> The equations are all reversible so you might say they are reversible >> with infinitesimal probability...but in most cases that reversal would >> mean catching and reversing photons that are already on their way >> outbound beyond the orbit of the Moon. >> >> Brent >> > > Are there any measurements that can't be reversed regardless of the > fact that the equations of physics are time reversible? I could swear, > and I DO, that Bruce demonstrated such a case for spin 1/2 particles > measured by SG device. AG >
You can always take a movie of the measurement and play it backward. Does this say anything about reversal in principle; that every measurement is in principle reversible? AG -- 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 https://groups.google.com/group/everything-list. For more options, visit https://groups.google.com/d/optout.
