On 25 Nov 2017, at 18:55, [email protected] wrote:
On Saturday, November 25, 2017 at 3:06:50 PM UTC, Lawrence Crowell
wrote:
On Thursday, November 23, 2017 at 9:21:14 PM UTC-6,
[email protected] wrote:
On Thursday, November 23, 2017 at 11:15:40 PM UTC, Lawrence Crowell
wrote:
I am new to this list and have not followed all the arguments here.
In weighing in here I might be making an error of not addressing
things properly.
Consider quantum entanglements, say the entanglements of two spin
1/2 particles. In the singlet state |+>|-> + |->|+> we really do not
have the two spin particles. The entanglement state is all that is
identifiable. The degrees of freedom for the two spins are replaced
with those of the entanglement state. It really makes no sense to
talk about the individual spin particles existing. If the observer
makes a measurement that results in a measurement the entanglement
state is "violently" lost, the entanglement phase is transmitted to
the needle states of the apparatus, and the individual spin degrees
of freedom replace the entanglement.
We have some trouble understanding this, for the decoherence of the
entangled state occurs with that state as a "unit;" it is blind to
any idea there is some "geography" associated with the individual
spins. There in fact really is no such thing as the individual
spins. The loss of the entangled state replaces that with the two
spin states. Since there is no "metric" specifying where the spins
are before the measurement there is no sense to ideas of any causal
action that ties the two resulting spins.
This chaffs our idea of physical causality, but this is because we
are thinking in classical terms. There are two ways of thinking
about our problem with understanding whether quantum mechanics is
ontic or epistemic.
The fact that probability waves evolve and interfere with each
other, and effect ensembles but not individual members, is
inherently baffling. So the wf can't be completely epistemic since
it modifies physical reality. That is, It must be ontic in some
respect, but in ways that defy rational analysis. AG
I think you are falling into a trap that David Hume warns against.
Causality gives rise to correlation, but correlation is not
necessarily the result of causality. There is no effect or some
causal principle at work with either individual wave functions or
wave functions in an ensemble of experiments. The ensemble of
experiments, the classic case being the two slit experiment, is
meant to deduces the wave nature of the quantum physics. It is not
there to deduce some causal influence underlying quantum nonlocality.
LC
Applying deBroglie's formula, a change in p changes the wave length,
and thus the distribution on the screen. That is, the ensemble
responds to changes in the wave length due to interference. I
therefore deduce that the wave length has a physical effect on the
ensemble, but not on individual outcomes. AG
But then how do you explain that there a parts of the screen where we
can predict that no photon at all will get there, even when sent
individually?
Bruno
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