Text Size


On Aug 22, 2010, at 2:26 PM, Paul Zielinski wrote:

On Sun, Aug 22, 2010 at 8:57 AM, JACK SARFATTI <sarfatti@pacbell.net> wrote:

No, that's not the way I understand the argument. The EPR argument is that without an action at a distance, the Heisenberg principle will be violated at one end of an entangled pair.

Which assumes EPR "locality" -- no *physical* influence can propagate faster than the speed of light.

Yes, the flow of the logic is that without spooky action at a distance connecting entangled real particles Heisenberg's uncertainty principle for one of the real particles can be violated (i.e. quantum theory is incomplete).

Note for local observables on a real particle outside the vacuum (neglecting gravitation hologram tiny black hole formation & mod factors of 1/2 etc)

&P&Q > <psi|[P,Q]|psi>

& = root mean square ensemble fluctuation

[ ] = commutator

P, Q are real Hermitian matrices with a basis in qubit Hilbert space.

but for a virtual particle inside the vacuum

Turn the argument on its head, i.e. entanglement + Heisenberg's uncertainty principle ---> spooky spacelike action at a distance

however this is only the Catch 22 "passion at a distance" the local uncontrollable randomness in the presence of nonlocal entanglement ensures signal locality.

&P&Q < <psi|[P,Q]|psi>
That is, given an entangled pair A, B if there were no physical disturbance connecting them, even across a spacelike separation outside the local light cones of the local measurements, then one, e.g. could know both simultaneous momentum and position of say particle A in violation of the local Heisenberg uncertainty principle.

According to the rules of standard QM one can predict the result of measuring the position of a spacelike separated subsystem, even while according to the EPR locality principle there can be no question that the measurement process *physically* disturbs the spacelike separated subsystem.

Right and that leads to an inconsistency with Heisenberg's microscope.
Of course we still have Shimony's "passion at a distance" that the local quantum randomness defeats any Nick Herbert FLASH scheme to send a message over a spacelike interval that can be decoded without a light cone limited key. Now this corresponds to Antony Valentini's "sub-quantal thermal equilibrium" of Bohm's hidden variables i.e. signal locality limit.

Contrary to what one would expect to occur if the propagating "disturbance" were truly physical.

However, in post-quantum theory beyond quantum theory we have sub-quantal non-equilibrium in which there is, in my theory, a stable two-way action-reaction (feedback control loop) between the entangled hidden variable "particles" and their piloting quantum potential Q(A,B) that permits signal nonlocality in direct violation of quantum theory's axioms.


Now the idea that a physical disturbance is not necessarily responsible for the alteration of a statistical expectation value of an observable Hermitian matrix is another story logically independent of the above, e.g. Yakir Aharonov's book "Quantum Paradoxes" (Vaidman bomb detector etc) - will come back to this.

I think historically Bohr did modify his position re: quantum measurement under pressure from EPR, but I guess that is all before Bell's work which showed that the statistical correlations predicted by QM for EPR-like scenarios are fundamentally incompatible with locality. So yes if you retain EPR locality there can be no question of A's measurement *physically* affecting the results of spacelike separated B's measurements, but as Bell showed even without making any interpretive assumptions regarding the nature of the influence, the predicted correlations themselves mathematically rule out locality in the stronger sense that A's measurement decisions can have no influence *of any kind* on the results of B's.

Clearly if the influence that Bell's argument shows must operate given the standard rules of QM were truly physical, then there should be no problem using such influences for signal propagation. So I suppose the $64K question here is, if the instantaneous influence is not truly physical, what is it?  

Yakir Aharonov's new book "Quantum Paradoxes" deals with these issues in detail. I plan to spend a lot of time on his book in the 2nd Edition of Space-Time and Beyond 2010

On Aug 22, 2010, at 3:35 AM, Paul Zielinski wrote:

I thought the Heisenberg microscope argument was already undermined by the 1935 EPR paper?

Wasn't Bohr forced by the EPR argument to renounce the idea that in quantum mechanics a *physical* disturbance is necessarily responsible for the alteration of the expected value of a physical quantity when any non-commuting quantity is measured?

On Sat, Aug 21, 2010 at 6:52 PM, JACK SARFATTI <sarfatti@pacbell.net> wrote: