The understanding of modal realism may be indicated from the results of this graphene experiment. It seems to postulate a twin, tidally locked world duo. It is, as it were, Everett's MWI interacting, perhaps down on Planck-ville? https://scitechdaily.com/our-reality-may-only-be-half-of-a-pair-of-interacting-worlds/ As Jim Morrison intoned, long ago, Break on through to the other side.
-----Original Message----- From: Brent Meeker <[email protected]> To: [email protected] Sent: Sun, May 15, 2022 3:30 pm Subject: Re: The Nature of Contingency: Quantum Physics as Modal Realism On 5/15/2022 12:11 AM, smitra wrote: > On 15-05-2022 00:55, Bruce Kellett wrote: >> On Sun, May 15, 2022 at 1:17 AM smitra <[email protected]> wrote: >> >>> On 13-05-2022 21:59, Brent Meeker wrote: >>> >>>> Right CI doesn't explain the collapse and MWI doesn't explain the >>>> collapse either but assumes it can be explained without new >>> physics. >>>> I hypothesize (not assume) that CI+ <non-zero minimum probability> >>> can >>>> explain the collapse. I don't see any big advantage for MWI here. >>> >>> The big advantage is that decoherence is a well researched area of >>> (mathematical) physics, results like the density matrix becoming >>> approximately diagonal, and relations between decoherence to entropy >>> >>> increase making it effectively irreversible are all rigorous results >>> >>> that are uncontroversial. People may still have objections against >>> the >>> MWI, but they'll still accept these results on decoherence. >> >> Yes. And decoherence says that with time, the off-diagonal elements of >> the density matrix become arbitrarily small. If there is a smallest >> non-zero probability, then eventually these off-diagonal elements >> become zero. This reduces the pure state to a mixture. Which is to say >> that there is a collapse; unitary evolution ceases, and we have >> reached a classical world. >> >>> Non-zero minimum probability on its own, however, does not cause a >>> system to evolve in a non-unitary way. >> >> It does when decoherence is taken into account. See the above >> explanation. Bruce has not omitted anything. >> >> Bruce > > I see, but these sorts of models can already be ruled out. There are > plenty of simple systems where one can make extremely accurate > measurements on which can be kept totally isolated and quantum > coherent for long enough where such effects would have become visible. If it's isolated the probability amplitudes are not changing so a non-zero minimum probability would have no consequence. You're thinking of experiments to refute spontaneous collapse theories; but I don't know that any have been done. GRW chose the parameters so the system has to be quite big in order to observe spontaneous collapse in reasonable isolation period. 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 view this discussion on the web visit https://groups.google.com/d/msgid/everything-list/e765b3b5-cf5c-7e4e-d8d6-42183ecbb6f7%40gmail.com. -- 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 view this discussion on the web visit https://groups.google.com/d/msgid/everything-list/1475201614.2029843.1652663101953%40mail.yahoo.com.
