On 30/11/2017 10:32 pm, agrayson2...@gmail.com wrote:
On Thursday, November 30, 2017 at 4:08:20 AM UTC-7, Bruce wrote:
On 30/11/2017 9:53 pm, agrays...@gmail.com <javascript:> 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
<bhke...@optusnet.com.au> 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.
*
*
*Why would it be non linear? Brent claimed (on page 1)*
Page 1 of what?*
*
*that if the QM could be made deterministic, say by a DE that
described collapse, it would imply awful consequences, such as the
future determining the past.*
No, it wouldn't imply that.
*Would making QM into a deterministic theory imply an inconsistency in
the postulates of QM? TIA, AG*
QM in MWI is deterministic. Bohm's theory is deterministic, though
expressly non-local. Determinism is not really an issue. One world
theories are intrinsically random, not deterministic.
Bruce
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