On 30/11/2017 9:53 pm, [email protected] wrote:
On Wednesday, November 29, 2017 at 10:40:36 PM UTC, Bruce wrote:
On 30/11/2017 5:31 am, John Clark wrote:
On Tue, Nov 28, 2017 at 10:59 PM, Bruce Kellett
<[email protected] <javascript:>> wrote:
>
I see no reason all the Everett worlds have the same
physics,
>
Everettian worlds follow from assuming that the
Schrödinger equation applies everywhere without exception,
so that all physical evolution is unitary. A change in the
underlying physics -- such as a change in the value of
fundamental constants, Planck's constant or Newton's
constant for example -- would not be unitary, so cannot
occur in MWI.
Why can't it be unitary?? Show me why if
Newton's constant had any value other than
6.754* 10^-11 m3 kg^−1 s^−2
the sum of all quantum probabilities would no longer add up to
exactly 1. If you can really do that then you've just derived
Newton's constant directly from first principles and you
should but a ticket to Stockholm right now because you're
absolutely certain to win the next nobel Prize.
Although unitarity does mean that probabilities always sum to
unity, that is a consequence of unitary evolution, not a
definition of it. A unitary transformation is one that can be
reversed: so the unitary operator U can be written as exp(-iH),
for example, and the complex conjugate (or the adjoint for
hermitian operators) is the inverse transformation.*
*
*
Considering the evolution of the wf, if there exists a DE that
describes the collapse process, would it necessarily be nonlinear? Is
nonlinear a problem; that is, what is the downside to nonlinear? How
would it effect the issue of hidden variables? TIA, AG *
Collapse would be non-linear and non-unitary -- intrinsically
non-reversible. This is not necessarily a problem since there are plenty
of non-linearities in physics. It has nothing to do with hidden variables.
Bruce
So for changes in constants to be unitary, there needs to be a
hermitian operator that brings about these changes. But changes in
constants only make sense for dimensionless constants such as the
fine structure constant, and there is currently no theory as to
how this would change in a unitary manner.
--
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.
