On 9/29/2019 6:53 PM, Bruce Kellett wrote:
On Thu, Sep 26, 2019 at 10:32 AM 'Brent Meeker' via Everything List
<[email protected]
<mailto:[email protected]>> wrote:
I think the alternative is something suggested by Zurek. He shows
that decoherence plus einselection will make the reduced density
matrix strictly diagonal, i.e. he solves the preferred basis and
derivation of the Born rule. Then he suggests, but doesn't really
argue, that the universe cannot have enough information to realize
all the non-zero states on the diagonal and so only a few can be
realized and that realization is per the Born rule. This is what
Carroll would dismiss as a "disappearing world interpretation";
but it would provide a physical principle for why worlds
disappear, i.e. branches of lowest probability are continually pruned.
I don't think this is exactly what Zurek is arguing. He mentions
Halliwell, but is concerned more with Quantum Darwism, which is an
account of the records left in the environment by the system, than
with the effects of decoherence on the system itself -- as would be
the case if the limits on environmental information set some
probabilities to zero. He says:
"Copying yields branches of records inscribed in subsystems of E.
Initial superposition yields superposition of branches, so there is no
literal collapse. However, fragments of E can reveal only one branch
(and not their superposition). Such evidence will suggest 'quantum
jump' from superposition to a single outcome...."
So it is the fact that our access is limited to only fragments of the
the entire environment that leads to the perception of collapse -- our
inability to see the superposition, or to reverse the measurement. If
you take only a portion of the complete state you certainly reduce the
pure state to a mixture. This is not a particularly new position,
being in line with the IGUS ideas of Gell-Mann and others.
That seems to be the same as MWI. Our access is limited because we are
in a relative state...so each copy me has limited access. Yet he refers
to "the myth of multiple worlds".
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/0bb5993d-f950-e1a9-f96c-56e0453de369%40verizon.net.
