On 2/22/2020 9:50 PM, Bruce Kellett wrote:
On Sun, Feb 23, 2020 at 4:30 PM 'Brent Meeker' via Everything List
<everything-list@googlegroups.com
<mailto:everything-list@googlegroups.com>> wrote:
On 2/22/2020 7:11 PM, Bruce Kellett wrote:
The trouble is that such a procedure is entirely arbitrary. The
only probability that one could objectively assign to say, W, on
each Bernoulli trial is one, since W certainly occurs for each
trial. In other words, there is no natural probability associated
with this duplication process, so imposing one is ad hoc and
arbitrary.
In MWI, it seems that Carroll gives the conventional answer --
weights are arbitrarily assigned to branches according to the
branch amplitude (modulus of the coefficient squared). This is
arbitrary too, designed merely to give the same answer that is
naturally obtained in the single world case. What I object to
about this is not only its arbitrariness, but also the fact that
it is advertised as a "derivation" from the SWE, when it is no
such thing. It is arbitrarily imposed.
It's imposed. But it's hardly arbitrary. First, it agrees with
experiment. Second, Gleason's theorem shows it's the only
mathematically consistent measure that could be used as a
probability. And Zurek tries to prove it's implied by symmetry
considerations.
It is imposed in such a way as to agree with experiment, yes. But that
is how the Born rule was arrived at in the first instance.
Consequently, MWI is no better than Copenhagen in this respect.
Gleason's theorem is only of use if you first assume that there is a
probability distribution -- that the theory is probabilistic. But
Everett is deterministic, not probabilistic.
And Everett recognized the problem and tried to derive the Born rule.
But I see as just overselling MWI. So it needs an axiom of probability
added to the deterministic evolution...no problem. The problem that
remains is decoherent diagonalization of the reduced density matrix is
only FAPP. Schlosshauer talks about doing a Schmidt decomposition to
make it strictly diagonal; but he recognizes that's just mathematical
transformation with not physical counterpart.
Brent
Zurek tries to explain it by symmetry considerations. But the basis of
his argument is the assumption that equal amplitudes imply equal
probabilities. Since the amplitudes do not affect the Everett
branching, this is ad hoc -- not a derivation.
Bruce
--
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
<mailto:everything-list+unsubscr...@googlegroups.com>.
To view this discussion on the web visit
https://groups.google.com/d/msgid/everything-list/CAFxXSLT-eCT5NePLEZVSw%3Dc%2BYafeNoW8nCYvLJQtHeDiEe4Gwg%40mail.gmail.com
<https://groups.google.com/d/msgid/everything-list/CAFxXSLT-eCT5NePLEZVSw%3Dc%2BYafeNoW8nCYvLJQtHeDiEe4Gwg%40mail.gmail.com?utm_medium=email&utm_source=footer>.
--
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 view this discussion on the web visit
https://groups.google.com/d/msgid/everything-list/de8b9567-2f67-4ef5-567e-28847808d803%40verizon.net.
