The Aharanov-Bohm (A-B) effect is one of the most fascinating aspects
of electromagnetism. It is generally recognized as being a QED
manifestation in which the Magnetic Vector Potential "A" can influence
the phase/trajectory of moving charges even when the magnetic field
associated with A is COMPLETELY ABSENT at the charge's location.

[snip]
It appears to me that the experimenters attempting to verify A-B have
taken extreme care to magnetically shield the solenoid. They have paid
less attention to electric shielding. A is a phenomenon associated
with E, so perfect magnetic shielding and less-than-perfect E
shielding may not be appropriate design choices.

It appears possible to me that the measured A-B effect is just an
ignored (or not understood) aspect of classical EM. I'd love to hear
what others -- that are familiar with Jefimenko's work and also
A-B --might think about this suggestion?

It appears possible to me that the measured A-B effect is just an ignored
(or not understood) aspect of classical EM. I'd love to hear what others --
that are familiar with Jefimenko's work and also A-B --might think about
this suggestion?

Well, the electron experiment is somewhat "rigged" from the beginning
since electrons are quantum objects and not classical objects. If you
are using quantum objects to begin with, then why would the results be
anything other than quantum mechanical? Has anyone ever done the
experiment with a more classical charged particle?

But I have always asked myself a question similar to yours. Surely the
"extended electric field" of the electron partially passes thru the
enclosed B field of the solenoid. But perhaps that is not enough to
cause the phase shift that is seen?

Best,

Fred Diether
Moderator sci.physics.foundations

"Bill Miller" <billmillerkt4ye@worldnet.att.net> wrote in message
news:K5%zi.53584$ax1.12717@bgtnsc05-news.ops.worldnet.att.net...
The Aharanov-Bohm (A-B) effect is one of the most fascinating aspects of
electromagnetism. It is generally recognized as being a QED manifestation
in which the Magnetic Vector Potential "A" can influence the
phase/trajectory of moving charges even when the magnetic field
associated with A is COMPLETELY ABSENT at the charge's location.

[snip]
It appears to me that the experimenters attempting to verify A-B have
taken extreme care to magnetically shield the solenoid. They have paid
less attention to electric shielding. A is a phenomenon associated with
E, so perfect magnetic shielding and less-than-perfect E shielding may
not be appropriate design choices.

It appears possible to me that the measured A-B effect is just an ignored
(or not understood) aspect of classical EM. I'd love to hear what
others -- that are familiar with Jefimenko's work and also A-B --might
think about this suggestion?

Well, the electron experiment is somewhat "rigged" from the beginning
since electrons are quantum objects and not classical objects. If you are
using quantum objects to begin with, then why would the results be
anything other than quantum mechanical? Has anyone ever done the
experiment with a more classical charged particle?

But I have always asked myself a question similar to yours. Surely the
"extended electric field" of the electron partially passes thru the
enclosed B field of the solenoid. But perhaps that is not enough to cause
the phase shift that is seen?

Best,

Fred Diether
Moderator sci.physics.foundations

FrediFizzx wrote:
Well, the electron experiment is somewhat "rigged" from the beginning
since electrons are quantum objects and not classical objects. If you
are using quantum objects to begin with, then why would the results be
anything other than quantum mechanical? Has anyone ever done the
experiment with a more classical charged particle?

Yes this is sort of true, but I'm not sure the results are "quantum
mechanical". A true "quantum mechanical" result would be the fact
that the electron can only go through one of the slits and yet
produces a double slit diffraction pattern.

But I have always asked myself a question similar to yours. Surely the
"extended electric field" of the electron partially passes thru the
enclosed B field of the solenoid. But perhaps that is not enough to
cause the phase shift that is seen?

And "extended" electron field could explain the double slit pattern,
but really isn't necessary to explain the A-B effect. The fact that
things happen in regions of zero B is like no surprise. Take the case
of induction outside a long solenoid or toroid. B is zero but A is
not!
We find in all these cases (as Feynman notes) that it is A that is the
determining quantity not B. In other words A is more fundamental than
B. So, I hear you cry, how can you have non-zero A with B being zero?
Simple. Suppose for example, you take the case of a long solenoid.
What is B outside the solenoid? Zero you say. Why? say I. Ampere's law
you say. And then I say but I can calculate B out there using Biot-
Savart. And you say, but that also Adds up to Zero B! And then I get
on my high horse and point out to you that you are worshiping
mathematics rather than physics! In math two equal opposite vectors
are required to sum to zero, in physics vectors may NOT be required to
sum to zero! Perhaps B vectors ONLY sum to zero in a magnetic field
sensor but are NOT summed to zero in space! Dig. A solenoid at any
outside point is a sum of the field from the top portion of the coils
going one way and a SECOND field from the bottom part of the coils
going the OTHER way! The two sum to zero IN A GAUSS METER. But do they
sum to "zero" in space? The answer MUST be they do NOT! And the
reason is that A is not zero out there! So in this little exercise we
see that suggestion of the A-B effect as "action at a distance" is as
bogus as the early "action at a distance" theories. There is no
mystery. A is the quantity that does the job. Take the Neumann
induction formula apart and you find it is A doing the job there too!

Hello Benj...

If you are suggesting by "A is the quantity that does the job" that it is an
omniscient and omnipresent entity, then I think we have a problem. What is
it about A -- other than a mathematical manipulation -- that allows its
(magnetic) presence to be felt in areas where no B is found? In fact, there
appears to be no restriction as to how far from the source of A that the
(theoretical) A-B effect can be measured, or the material through which it
can be measured. And that makes the whole thing very suspect to me.

That's why I suggested that the (measured) A-B effect is not due to Magnetic
field influence, but is an Electrical.field function with properties that
are different from those of "standard" E field analysis.

If you haven't (yet) gotten -- and read -- Jefimenko's book, then I'm not
sure I can take this much further without transcribing several dozen pages
of differential equations into something readable on list.

Bill Miller wrote:

If you are suggesting by "A is the quantity that does the job" that it is
an
omniscient and omnipresent entity, then I think we have a problem. What
is
it about A -- other than a mathematical manipulation -- that allows its
(magnetic) presence to be felt in areas where no B is found? In fact,
there
appears to be no restriction as to how far from the source of A that the
(theoretical) A-B effect can be measured, or the material through which
it
can be measured. And that makes the whole thing very suspect to me.

I am suggesting that it is "A" that does the job. I'm not suggesting
that it is omniscient and omnipresent. (A can be Zero, you know!) >My
point is that there could be a difference (in fact it appears there IS
a difference) between B being zero and B MEASURING zero.

As for distance, I doubt that the A-B effect has no distance
limitation. Jeeze, in that case EVERY magnet in the universe would
affect your measurements!

A does fall off as 1/x which is less rapid
than B.

As for going through materials, Both B and A go through
materials. You really can't shield a magnetic field (as far as I
know). The usual ferromagnetic shields actually only set up opposing
fields that cancel the original. (same idea as B only measuring
zero).

That's why I suggested that the (measured) A-B effect is not due to
Magnetic
field influence, but is an Electrical.field function with properties that
are different from those of "standard" E field analysis.

Dunno. Could be. There are really three E fields. Bridgeman in his
book "The logic of Modern Physics" goes for an "operational"
categorization. Namely that you have Three different charge operations
(position, velocity, and acceleration) which give rise to three
different kinds of E fields. Electrostatic, motional, and inductive.
Maxwell's "one E field" idea is clearly wrong.

If you haven't (yet) gotten -- and read -- Jefimenko's book, then I'm not
sure I can take this much further without transcribing several dozen
pages
of differential equations into something readable on list.

Keep after me! You know what the road to where is paved with!!!!

Benj

affect your measurements! A does fall off as 1/x which is less rapid
than B. As for going through materials, Both B and A go through
materials. You really can't shield a magnetic field (as far as I
know). The usual ferromagnetic shields actually only set up opposing
fields that cancel the original. (same idea as B only measuring
zero).

"Benj" <bjacoby@iwaynet.net> wrote in message
Bill Miller wrote:

OK If it doesn't look like a duck, doesn't quack like a duck, doesn't swim
or fly like a duck, and isn't present when we look for it, then it can still
be a duck?

I agree that shielding anything to zero is hopeless, because there will
always be a residual something there. (That's where homeopathic medicine
came from. The less of something that you use, the more effective it is. Try
that in a battle. But I digress.)

If we have shielded something to the point that we can't measure it any
more, and the A-B effect is still present, then I think we are shielding the
wrong thing!

As for distance, I doubt that the A-B effect has no distance
limitation. Jeeze, in that case EVERY magnet in the universe would
affect your measurements!

My point exactly!

A does fall off as 1/x which is less rapid
than B.

True. But A is a function of the rate of change of Ek WRT time -- ie. it can
be looked at as an impulse function.. And Ek is a function of velocity (of
the electrons).

We may be saying almost the same thing, but you continue to assume that A-B
is a magnetic phenomenon -- albeit a self canceling one (?) -- and that's
what I am questioning.

Yep. In Bridgeman's book, does he quantify the three fields? See page 13 of
Jefimenko's "Causality..." book for a complete definition of these three
fields.

Oh. Yeah. I forgot. You haven't gotten the book yet.

:-)

BTW Kirk's page has several interesting papers by Jefimenko (and Carpenter).
Don't know if you've looked at them.

"FrediFizzx" <fredifizzx@hotmail.com> wrote in message
news:5jbfeoF3sh2fvU1@mid.individual.net...
"Bill Miller" <billmillerkt4ye@worldnet.att.net> wrote in message
news:K5%zi.53584$ax1.12717@bgtnsc05-news.ops.worldnet.att.net...
The Aharanov-Bohm (A-B) effect is one of the most fascinating
aspects of electromagnetism. It is generally recognized as being a
QED manifestation in which the Magnetic Vector Potential "A" can
influence the phase/trajectory of moving charges even when the
magnetic field associated with A is COMPLETELY ABSENT at the
charge's location.

[snip]
It appears to me that the experimenters attempting to verify A-B
have taken extreme care to magnetically shield the solenoid. They
have paid less attention to electric shielding. A is a phenomenon
associated with E, so perfect magnetic shielding and
less-than-perfect E shielding may not be appropriate design choices.

It appears possible to me that the measured A-B effect is just an
ignored (or not understood) aspect of classical EM. I'd love to hear
what others -- that are familiar with Jefimenko's work and also
A-B --might think about this suggestion?

Well, the electron experiment is somewhat "rigged" from the beginning
since electrons are quantum objects and not classical objects. If
you are using quantum objects to begin with, then why would the
results be anything other than quantum mechanical? Has anyone ever
done the experiment with a more classical charged particle?

But I have always asked myself a question similar to yours. Surely
the "extended electric field" of the electron partially passes thru
the enclosed B field of the solenoid. But perhaps that is not enough
to cause the phase shift that is seen?

Well... I guess we can look at the activity of electrons in a quantum
way -- for the reasons you state. But I have read an awfully lot of
books and papers in which electrons are treated as non-quantum
devices.