On 4/4/2022 8:46 PM, Bruce Kellett wrote:
On Tue, Apr 5, 2022 at 12:15 PM Brent Meeker <meekerbr...@gmail.com>
wrote:
This paper https://arxiv.org/pdf/quant-ph/0103079.pdf gives an
explicit account of an EPR type experiment which says observers
are "labeled" so that only the compatible observes can communicate.
So, the splitting of each observer into copies at each
measurement interaction is represented by the local dynamics of
the operators describing their states of awareness relative to
what they were at the initial time t0; in particular, the
possibilities for interaction of observers of entangled systems
are determined by the labels attached to the operators.
Determination of the number of each type of observer-copy produced
at each splitting, as well as the specific state of awareness of
each type of observer-copy, involves information 14 about the
initial conditions of the system, information which in the
Heisenberg picture is contained in the time t0 state vector.
(DeWitt (1998) emphasizes that quantum systems are “described
jointly by the dynamical variables and the state-vector.”) Just as
observers or other entities may be regarded as receiving and
carrying with them, in a local manner, the labels described above,
they may also be envisioned as carrying with them in a similarly
local manner the requisite initial-condition information.
Since one cannot argue for the existence of counterfactual
instruction sets, the conditions of Bell’s theorem do not apply.
Had angles other than those that actually were used been chosen
for the analyzer magnets, copies of each observer carrying labels
appropriate to those angles would have resulted. There are indeed
“instruction sets” present; but they determine, not the results of
experiments which were not performed but, rather, the
possibilities for interaction and information exchange between the
Everett copies of the observers who have performed the experiments.
Bohr’s reply to EPR can also be reinterpreted in the present
context. Regarding correlations at a distance, Bohr (1935) states
that “of course there is in a case like that just considered no
question of a mechanical disturbance of the system under
investigation during the last critical stage of the measuring
procedure. But even at this stage there is essentially the
question of an influence on the very conditions which define the
possible types of predictions regarding the future behavior of the
system.” The Everett splitting and labeling of each observer
constitutes just such an influence, determining the possible types
of interactions with physical systems and observers which the
observer can experience in the future without in any way producing
a “mechanical disturbance” of distant entities.
The Everett interpretation in the Heisenberg picture thus
removes nonlocality from the list of conceptual problems of
quantum mechanics. The idea of viewing the tensor-product factors
in the Heisenberg-picture operators as in some sense “literally
real” introduces, however, a conceptual problem of its own.3
Entanglement via the introduction of nontrivial “label” factors is
not limited to interactions between two or three particles; each
particle of matter is labeled, for eternity, by all the particles
with which it has ever interacted. What is the physical mechanism
by means of which all of this information is stored? The issue of
“where the labels are stored” may seem less problematic in the
context of the Everett interpretation of Heisenberg-picture
quantum field theory. After all, in quantum field theory,
operators corresponding to each species of particle and evolving
according to local differential equations already reside at each
point in spacetime. (In the EPRB and GHZM experiments the
particles in question are considered to be distinguishable and so
may be treated, for purposes of analyzing the experiments, as
quanta of different fields. More complicated objects, such as
observers and magnets, might be approximated as excitations of
effective composite fields, following, e.g., Zhou et al. (2000).)
Even in the event that such a program for a literal, indeed
mechanistic picture of measurement in quantum field theory cannot
be realized, it remains the case that Everett’s model for
measurement in the Heisenberg picture provides a quantum formalism
which is explicitly local and in which the problem of Bell’s
theorem does not arise.
What do you make of this?
I couldn't figure out how the "labels" actually implemented contrary
observers meeting?
Brent
Others have referred me to the Rubin paper. I have looked at it, and
remain unimpressed. He claims that "Bell's theorem is avoided because
the counterfactual reasoning that leads to it is not required and
cannot be justified." This is nonsense. Bell's theorem does not
require counterfactual reasoning, and the experiments by Aspect and
others only record the results of measurements that were actually
made-- there is no reference to measurements that were not performed
at other angles. Measurements that are not performed have no results.
More seriously, he has an undisguised appeal to magic in
statements such as:
"When the two observers -- or, more precisely, the two pairs of
observer-copies -- exchange information about the results of their
measurements, it is the attached labels which ensure that the
"correct" copies of each of the observers interact; e.g., preventing
two observers-copies who have both observed spin-up from communicating."
A more direct appeal to magic is hard to envisage. The 'labels' that
he says the Heisenberg picture attaches do no work that was not
already done by the actual results. Furthermore, there is no
indication as to what interaction occurs when the observers meet, and
no indication as to how this supposed interaction does the work that
is required of it. What happens to the "incorrect" aobserver pairs?
This is unbridled nonsense, and I am sick of responding to nonsense
papers of this sort.
Bruce
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