On 01 Dec 2017, at 00:20, [email protected] wrote:
On Thursday, November 30, 2017 at 11:16:07 PM UTC,
[email protected] wrote:
On Thursday, November 30, 2017 at 9:47:37 PM UTC, Bruce wrote:
On 30/11/2017 10:59 pm, [email protected] wrote:
On Thursday, November 30, 2017 at 11:42:51 AM UTC, Bruce wrote:
On 30/11/2017 10:32 pm, [email protected] wrote:
On Thursday, November 30, 2017 at 4:08:20 AM UTC-7, Bruce wrote:
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]> 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?
On Google it's organized as pages, now up to page 15. Go to top of
thread and read second message by Brent. AG
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.
How can MWI be deterministic if it can't tell us what outcome we
will observe in this world, or any other? AG
Because MWI says that all outcomes are realized, each in a separate
world. Apparent randomness comes about because we don't know which
world we will end up in (though we actually end up in all the
worlds, so we, or our duplicates, observe all possible outcomes).
Bruce
OK. I wouldn't use "deterministic" to describe that situation, but
that's neither here nor there.
More important is Brent's reply to my question which started this
discussion thread. He stated that a deterministic ONE WORLD version
of QM would have dire effects, such as the future influencing the
past. His exact words are in the 2nd message in this discussion. You
don't seem to share this view. I know that Bohm developed a
deterministic version of QM which is expressly non-local and not
covariant. I don't think it's what Brent was referring to.
Also, I noticed that Bruno, our resident enthusiast of arithmetic as
the solution to all enigmas,
That is very elegant mathematically, but I am not necessarily
enthusiast about this, and sometimes I call Mechanism terrifying
thinking. At the first sight it entails that agonies are infinite, as
your consciousness survives in the closest environment/computations
logically possible, and there are an infinity of them. Nothing funny
there.
The point is that it is a logical consequence of what is perhaps the
oldest hypothesis in science: that life is a mechanism. Of course, the
infinite agony might end ... because things are more subtle when doing
the math, so no need to despair prematurely of mechanism either.
Computer science suggests some "jumps", which makes the prediction
there very difficult, but all in all, sometimes I wish death is an
end. That is made impossible with mechanism, as Descartes and many
others intuited correctly.
This entails also that, in physics, Everett, who used a rough informal
form of Mechanism, has done only one half of the work. It remains to
explain the wave itself phenomenologically. It is not a matter of
choice but of intellectual rigor. Invoking Primary Matter in a
mechanist metaphysics is as much wrong than invoking God in the
explanation of the existence of the universe. It just doesn't work. It
is not logically valid. That does not mean that God does not exist,
but it means that it cannot be used in explanation, nor in moral (!).
The case of Pirmary Matter is worst, it leads to inconsistencies (with
even very weak form of Mechanism).
stated that Weinberg showed that a non-linear SWE to explain
collapse would imply that the laws of thermodynamics are flawed. Is
this your understanding?
Somehow, yes. Weinberg wrote a paper(*) showing that if we assume that
the fundamental wave equation is non linear, and still getting the QM
predictions already verified, then the "parallel universes" can
interact with each others, and that this possibility entails the need
to abandon almost all of today's physics. The conclusion is that it is
foolish to try to solve the conceptual problem of QM by searching a
non linear equation in place to the usual linear one. Even Bohm add a
non linear potential, but keep the linear SWE.
Bruno
(*) I don't find my old photocopy, but I am pretty sure you will find
it (and many related papers) by searching on "weinberg's nonlinear
quantum mechanics".
TIA, AG
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