On 09 Dec 2017, at 13:00, smitra wrote:
On 09-12-2017 12:01, Bruce Kellett wrote:
On 9/12/2017 9:44 pm, smitra wrote:
On 09-12-2017 02:48, Bruce Kellett wrote:
On 9/12/2017 11:49 am, smitra wrote:
On 09-12-2017 00:03, Bruce Kellett wrote:
On 9/12/2017 4:21 am, Bruno Marchal wrote:
On 08 Dec 2017, at 00:22, Bruce Kellett wrote:
On 8/12/2017 3:31 am, Bruno Marchal wrote:
On 06 Dec 2017, at 12:19, Bruce Kellett wrote:
But as I pointed out, thermal motion gives momenta of
magnitudes such that the quantum uncertainties are
negligible compared to the thermal randomness. And thermal
motions are not coherent.
You seem to work in Bohr QM, with some dualism between the
quantum reality and the classical reality.
Not at all. The (semi-)classical world emerges from the
quantum substrate; if you cannot give an account of this,
then you have failed to explain our everyday experience. And
explaining that experience is the purpose of physics.
No problem with this, except for your usual skepticism of
Everett's program (say).
Skepticism is the scientific stance.....
You are right that this does not change anything FAPP, but
our discussion is not about practical applications, but
metaphysics.
No, we were talking about tossing a coin, we were not talking
about metaphysics. Your metaphysics has served merely to
confuse you to the extent that you do not understand even the
simplest physics.
That is ad hominem remark which I take as absence of argument.
You don't take kindly to criticism, do you Bruno?
All I said is that without collapse, shaking a box with some
coin long enough would lead to the superposition of the two
coin state. You seem to be the one confusing the local
decoherence with some collapse. The Heisenberg uncertainties
are great enough to amplify slight change of the move of the
coin when bouncing on the wall.
That is simply assertion on your part, without a shred of
argument or
justification. When one looks at the arguments, such as that put
forward by Albrecht and David (referred to by smitra), one
finds that
the emperor has no clothes!
Similarly, a shroedinger car, once alive + dead, will never
become a pure alive, or dead cat. It will only seems so for
anyone looking at the cat, in the {alive, dead} base/
apparatus. Superposition never disappear, and a coin moree or
less with a precise position, is always a superposition of a
coin with more or less precise momenta. The relation is given
by the Fourier transforms, which gives the relative accessible
states/worlds.
I pointed out that for a macroscopic object such as a coin, the
uncertainty relations give uncertainties in positions and/or
momentum
far below any level of possible detection. And I gave an
argument with
an actual calculation -- not just an assertion. Uncertainties
in the
constituents of the object are uncorrelated, random, and cancel
out.
So although the superposition originating from the big bang is
intact
from the bird's point of view, it is so completely irrelevant for
everyday purposes that it is an insult to even refer to the
classicality of the world as FAPP -- it is complete. Relying on
the
charge of "FAPP" as a justification for your assertions is
nonsense.
It's not irrelevant if you don't have the information that
locates you in a sector where the uncertainties are indeed small
enough. You have to start with the complete state in the bird's
view, and then consider the sector where you have some definite
information and then project onto that subspace. If you do that,
then your coins are not at all in a precisely enough classical
state but rather in superpositions (entangled with the
environment) that lead to wildly different outcomes of coin
tosses.
E.g. in the bird's view there exists exact copies of me that
live on planets that are not the same, some will have a radius
of a few millimeter larger than others. Here exact copy means
exactly the same conscious experience, which is then due to
exactly the same computational state of the brain described by
some bitstring that's exactly the same.
So, from totally different decoherent branches of the
wavefunction one can factor out some bitstring describing a
conscious experience, the reduced state of the rest of the
universe in that sector is then a superposition of a many
different effectively classical states.
If this were not true then each single conscious experience
would contain in it information about such things as the exact
number of atoms in the Earth, Sun etc. etc.
I prefer to live in the real world, so I would rather not indulge
your
fantasies.
The real world is not what you think it is. It was only when you
read about the fact that dinosaurs had once existed that the
sector you were in diverged from other sectors where dinosaurs had
never existed and some other evolutionary path of mammals led to
you and the exact same information in your brain before becoming
aware of the existence of dinosaurs.
Evidence?????
This is generically the case in a MWI setting. Of course, the MWI
may not be correct, QM may not be the ultimate foundation of the
laws of physics, but if we assume the MWI, then some observer who is
aware of precisely the information specified by some bitstring b
(and nothing more or less than specified by b), the observer should
consider him/herself to be in a superposition of all branches where
b appears in.
So, when you project the global quantum state on the subspace
spanned by b you get the superposition of all branches that are
relevant to b. Then when the observer adds one bit to b, e.g.
whether not dinosaurs once roamed the Earth, the state gets reduced
further.
I agree qualitatively, but personally, I think it might even not
applied to the far away "young" galaxies, because, even before we
detect them, they were detectable in principle. And that is even more
true for the dinosaurs which have leave so many results of their
interaction with earth in the past. So although I agree with the idea,
I am not sure it applies for the major past history, although it does
apply to the early origin.
The quantum vacuum is already a universal quantum dovetailer, but with
mechanism, we must explain why the quantum dovetailer seem to win from
the 1p view, by a measure on all computations.
We know that the h -> e^iH quantization solves the problem by phase
randomization (feynman). Now we must show, using comp, that it is the
only solution, and this from G/G* (so we get the qualia too). (But
this requires a bit of mathematical logic).
Bruno
Saibal
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