Re: Visualizing the quantum world...

Date: Thu, 9 Nov 1995 14:59:29 -0800
From: Jack Sarfatti <sarfatti@ix.netcom.com>
Reply to: quantum-d@teleport.com
To: quantum-d@teleport.com
Subject: QUANTUM-D: Re: Visualizing the quantum world...

Welcome to Bohmland...

Vic Stenger wrote: 

>"The familiar picture of particles following definite paths through
> spacetime can be retained to visualize the behavior of fundamental
> particles, as long as we allow their spacetime worldlines to wander
> around at will within both forward and backward lightcones."

Well Bohm's theory has this feature. That's what the quantum
potential does. What is new here? Has Vic reinvented the Wheeler?
:-) Welcome to Bohm Land. 

Rhett commented:

>I will hazard a comment. While i find these images interesting
>and meaningful, i see no reason to regard them as an exorcism or
>minimization of "nonlocality." 

Right. The nonlocality is in the quantum force that makes the
particle deviate from the orbits predicted by the classical
potential.

The actual hidden variables of Bohm's theory are simply the
initial data on the positions of the actual particles (in simplest
NR case). The "superluminal" stuff is in the quantum potential
term in the Hamilton-Jacobi equation of motion for the particles.

Vic wrote:

>Bohr's position won the day and came to be part of what
>is known as the Copenhagen  interpretation, the orthodox  view
>of quantum mechanics.   It remains today consistent with all
>observations.  However, Copenhagen expresses an ontology that
>has become the source of much metaphysical speculation in
>which human consciousness is given a role that is
>unprecedented in physical theory...

Yes - all the New Age stuff is Bohr's fault. Actually it is
John Wheeler's fault. John was our Pied Piper. 

>Here I wish to propose a way to verbalize and visualize
>quantum mechanics  in terms of the familiar concepts of
>particles moving along well-defined paths through space, with
>definite speeds and directions, that the average person should
>find comprehensible.   Furthermore, I hope to show that the
>mystical consequences associated with Copenhagen and several
>other interpretations can be avoided with this picture.

Bohm has already done this - starting in 1952.

>                                 Fundamental processes do not
>follow a preferred arrow of time.  Without an arrow of time,
>we have no causality or determinism.  And without causality
>and determinism, we have none of the paradoxes that have
>become associated with quantum mechanics and which are used
>to support mystical claims.  Since everything from common
>experience tells us that time flows one way, this represents
>the most difficult conceptual leap that must be take in the
>process.  However, once this is done, the claimed paradoxes of
>quantum mechanics that lead us down the road to mysticism
>disappear and particles move through space and time just as
>they always did--along definite paths and with definite
>momenta. 

Well I have been arguing for violation of causality...

>                            However, the collapse
>of the wave function is not predicted by the Schrodinger
>equation, and indeed is inconsistent with it.

Right, no collapse in Bohm's theory.

>Usually the time-reversed solutions in classical and
>quantum mechanics are ignored, with no reason given.  As I
>will argue below, this is an arbitrary procedure that has no
>justification other than agreement with preconceptions that
>have been conditioned by our macroscopic experience.

I have said this for a long time also.

>In their book The Arrow of Time, Coveney and Highfield
>even go so far as to suggest that the macroscopic arrow of
>time can explain the paradoxes of quantum mechanics, although
>they do not say how.[11]  My thesis is the exact opposite, that a
>recognition that time has no arrow at the quantum level
>actually eliminates the so-called paradoxes of quantum
>mechanics.  The paradoxes result only when we try to force our
>macroscopic prejudices on quantum systems.

However, the principle of microcausality in field theory seems
to be connected with the arrow of time. One consequence is that
causes must be before effects. The word "before" is the arrow
of time. In order for the arrow to exist there must not be
any faster than light quantum influences. In Bohm's theory the
faster than light influence is in the quantum potential and
the classical limit is when the quantum potential is neglibible.
Therefore, the classical limit is when there can be an arrow of 
time. So I have quickly deduced the true part Vic's thesis in 
an elementary way directly from Bohm's theory. That is, it is 
the nonlocality of the quantum potential which prevents an arrow 
of time at the quantum level.

>III.  EFFECTIVE NONLOCALITY
>The terms local and nonlocal frequently appear in the quantum
>literature.  Basically they refer to whether two events in
>spacetime have timelike or spacelike separations.  If the
>separation is timelike, inside the light cone, a reference frame
>can be found in which the two events are in the same place, and
>so are local.  If the separation is spacelike, outside the light
>cone, such a reference frame cannot be found without
>superluminal motion.  Then the events are nonlocal.
>Relativity by itself does not deny nonlocality or
>superluminal motion.  It simply forbids the acceleration of
>particles with non-zero rest mass to or beyond the speed of
>light.  

Yes.

>Quantum phenomena are widely thought to be nonlocal.
>However, this need not imply superluminal motion.

Yes, that is what Bohm's theory says. The motion of the particle
is subluminal - but the quantum force acts superluminally. The
near field of Coulomb also acts superluminally. The difference is
that the quantum force is context of state-dependent.

>                                          As I will
>now demonstrate, effective nonlocality can happen without
>motion faster than the speed of light...

Nowhere in Bohm's theory does one say that nonlocality is due to 
faster than light motion of the particle. 

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