On 30 Nov 2017, at 11:53, [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
For the hidden variable theory, I don't know, but for the MWI, if you
delinearise the SWE, it makes the parallel universe accessible, caable
of intercation between each others. You can in principle chat with
your doppelgangers. It makes also the second laws of thermodynamic
wrong, and SR, GR, etc. (I got this from a paper by Weinberg, and by
Plaga who participated to the list I think, before me).
For the Bohm hidden variable theory, it would be like being able to
visit the parallel worlds too, but they would not have particles, nor
consciousness, despite we would'nt see that, as it is only the shape
of the potential functions which would deluded us, by a non local
process, into seeing those parallel worlds.
Bruno
PS ... busy days so sorry for possible delays in the comments.
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.
>> lets assume you're right, then the string theory
multiverse must be larger than the many worlds multiverse
incorporating everything in Everett's version and MORE; after all if
it contains universes with radically different laws of physics it
must also contain more modest things like a world where my coin came
up heads instead of tails.
> I would suggest that there is no such world. Whether a coin
comes up head or tails on a simple toss is not a quantum event;
Do you actually think reality can be neatly divided
between quantum and non-quantum events? A unstable atom has a 50%
chance of decaying and producing a easily detectable high speed
electron, if the electron is detected a computer controlled robot
arm turns my coin to heads, if it detects no electron it turns my
coin to tails.
Of course, if you set up a situation in which a quantum event is
amplified to give a difference in macroscopic outcomes, such as in
Schrödinger's cat, then you can say that the macroscopic uncertainty
has a quantum origin. But the majority of quantum events are not
amplified in this way -- they simply occur randomly in large numbers
so that the expectation value is unaffected by individual
uncertainties.
> Also, in the Level I multiverse it is quite unlikely that
the initial conditions could differ to an extent such that
everything was identical in the two worlds up to your coin toss.
Quite unlikely events are going to happen if the number of
universes is large enough, and if there are a infinity of
worlds then anything with a non-zero probability is
certain to happen in some universe.
Except events of measure zero.
> Worlds are not random objects, they follow the laws of
physics, so given some initial conditions, the future is determined i
...
--
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.
http://iridia.ulb.ac.be/~marchal/
--
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.
