On Saturday, October 20, 2018 at 5:39:28 PM UTC, [email protected] wrote: > > > > On Friday, October 19, 2018 at 9:08:47 PM UTC, Brent wrote: >> >> >> >> On 10/19/2018 10:59 AM, [email protected] wrote: >> >> >> >> On Friday, October 19, 2018 at 5:44:10 PM UTC, Brent wrote: >>> >>> >>> >>> On 10/19/2018 12:17 AM, [email protected] wrote: >>> >>> *I can see how recoherence is impossible FAPP, but after some time >>>> elapses the state of the cat could Dead or Alive; not necessarily the >>>> original state, Alive. A*G >>>> >>>> >>>> When recoherence is no longer possible that's a real physical change. >>>> The system has evolved. >>>> >>> >>> *Since decoherence is a unitary process, isn't recoherence always >>> possible, even if not FAPP? AG* >>> >>> >>> Sure. If you could reverse the outgoing waves and the local universe. >>> >> >> *Since recoherence is always possible, even if astronomically unlikely >> like many physical macro processes, why do you make the point that there's >> a real physical change when it's no longer possible (which is never)? I >> ask because your comment is confusing. AG* >> >> >> That's the real physical change. Outgoing radiation has left at the >> speed of light out into an expanding universe; it ain't comin' back. Why >> is that confusing? >> > > > *You seem to conflate two concepts; Irreversible FAPP, and Irreversible > (aka Absolutely Irreversible, aka Irreversible in Principle). I tend to > believe that every unitary process is either easily reversible, or > irreversible FAPP (meaning possibly reversible even if hugely improbable). > In the case of two closed containers attached to each other, one in vacuum > state and the other filled with gas at some temperature, one can imagine > all the gas in one container finally equalizing in both containers. That > would occur in finite time, but is Irreversible FAPP. In your example > above, one can imagine the outgoing photons bending around super dense > masses and returning to their original positions or states. So I would say > this outcome is Irreversible FAPP, but you say it's Irreversible, meaning > Absolutely Irreversible or Irreversible in Principle. So which is it? AG * > > *The more interesting issue is whether the WF in the Cat experiment, or > for an atom with a half life for decay, evolves in time while the box is > closed. I say it must evolve because the probability amplitudes are time > dependent. What say you? AG* >
*Seriously; if the wf for a radioactive atom evolves in time, why would placing it in a box change that (or do I misunderstand what you and Bruce are claiming)? AG * > > > >> Brent >> > -- 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.
