I have recently completed reading "Deep Down Things" by Bruce Schumm.
It it Bruce gives an excellent description of how quanta behave
relative how particles of like charge repel each other. However, there
is no description of how particles of opposite charge attract each
other.

Is the a similar explanation of how particles of opposite charge
attrack each other through such quanta?

jswalsh@ix.netcom.com schrieb:
I have recently completed reading "Deep Down Things" by Bruce Schumm.
It it Bruce gives an excellent description of how quanta behave
relative how particles of like charge repel each other. However, there
is no description of how particles of opposite charge attract each
other.
Is the a similar explanation of how particles of opposite charge
attrack each other through such quanta?

It doesn't work. Exchange particles are ''virtual particles''
- as the name says, purely fictitious objects -, introduced solely
to let the complicated multidimensional integrals arising in quantum
field theory (and abbreviated by Feynamn diagrams) look somewhat
tangible. See the entry ''How real are 'virtual particles'?''
in my theoretical physics FAQ at
http://www.mat.univie.ac.at/~neum/physics-faq.txt

Thus any 'explanations' of what virtual particles do is meaningless.
You could as well ask how the person (virtual image) in the mirror
you are looking manages to move its hand when you lift your hand.

Thus spake Arnold Neumaier <Arnold.Neumaier@univie.ac.at

[...] Exchange particles are ''virtual particles''
- as the name says, purely fictitious objects -, introduced solely
to let the complicated multidimensional integrals arising in quantum
field theory (and abbreviated by Feynamn diagrams) look somewhat
tangible. See the entry ''How real are 'virtual particles'?''
in my theoretical physics FAQ at
http://www.mat.univie.ac.at/~neum/physics-faq.txt

Thus any 'explanations' of what virtual particles do is meaningless.
You could as well ask how the person (virtual image) in the mirror
you are looking manages to move its hand when you lift your hand.

This is often asserted as though a definite fact, but it is actually
just a point of view, one to which Feynman himself did not subscribe. He
considered that we should not distinguish between real and virtual
particles.

I have recently completed reading "Deep Down Things" by Bruce Schumm.
It it Bruce gives an excellent description of how quanta behave
relative how particles of like charge repel each other. However, there
is no description of how particles of opposite charge attract each
other.

Is the a similar explanation of how particles of opposite charge
attrack each other through such quanta?

Thus spake Arnold Neumaier <Arnold.Neumaier@univie.ac.at
jswalsh@ix.netcom.com schrieb:
I have recently completed reading "Deep Down Things" by Bruce Schumm.
It it Bruce gives an excellent description of how quanta behave
relative how particles of like charge repel each other. However, there
is no description of how particles of opposite charge attract each
other.
Is the a similar explanation of how particles of opposite charge
attrack each other through such quanta?

Yes. The same description works equally well although it is a little
less obvious.

It doesn't work. Exchange particles are ''virtual particles''
- as the name says, purely fictitious objects -, introduced solely
to let the complicated multidimensional integrals arising in quantum
field theory (and abbreviated by Feynamn diagrams) look somewhat
tangible. See the entry ''How real are 'virtual particles'?''
in my theoretical physics FAQ at
http://www.mat.univie.ac.at/~neum/physics-faq.txt

Thus any 'explanations' of what virtual particles do is meaningless.
You could as well ask how the person (virtual image) in the mirror
you are looking manages to move its hand when you lift your hand.


This is often asserted as though a definite fact, but it is actually
just a point of view,

one to which Feynman himself did not subscribe. He
considered that we should not distinguish between real and virtual
particles.

On 2007-02-08, Oh No <NotI@charlesfrancis.wanadoo.co.uk> wrote:
Thus spake Arnold Neumaier <Arnold.Neumaier@univie.ac.at

[...] Exchange particles are ''virtual particles''
- as the name says, purely fictitious objects -, introduced solely
to let the complicated multidimensional integrals arising in quantum
field theory (and abbreviated by Feynamn diagrams) look somewhat
tangible. See the entry ''How real are 'virtual particles'?''
in my theoretical physics FAQ at
http://www.mat.univie.ac.at/~neum/physics-faq.txt

Thus any 'explanations' of what virtual particles do is meaningless.
You could as well ask how the person (virtual image) in the mirror
you are looking manages to move its hand when you lift your hand.

This is often asserted as though a definite fact, but it is actually
just a point of view, one to which Feynman himself did not subscribe. He
considered that we should not distinguish between real and virtual
particles.

There are many points of view and yours maybe one of them, Feynman's may
be another, and mine a third. All of these points of view may be equally
valid and allowed to disagree when discussing physics informally.

However, the same can no longer be said when we leave the informal realm
in favor of the quantitative and scientific one. Then, a physicist, that
considers the question "What is a virtual particle?" in earnest, will
not be able to find a definition that satisfies what is usually mean by
both "virtual" and "particle".

The only definition that I know of that most can agree on is: a "virtual
particle" is an internal line on in a Feynman diagram. Since Feynman
diagrams only lives on paper, then so do virtual particles. A
quantitative treatment of these wiggly lines on papar as "particles" is
truly impossible.

Oh No schrieb:

Thus any 'explanations' of what virtual particles do is meaningless.
You could as well ask how the person (virtual image) in the mirror
you are looking manages to move its hand when you lift your hand.


This is often asserted as though a definite fact, but it is actually
just a point of view,

It is the only correct point of view.

There is no way to observe
virtual particles, and the name was chosen to reflect this.

Observed particles are always onshell, hence massless for photons,
whereas it is an easy exercise that the virtual photon mediating
electromagnetic interaction of two electrons in the tree approximation
is never onshell.

one to which Feynman himself did not subscribe. He
considered that we should not distinguish between real and virtual
particles.

Please give a reference, not from his writing for laymen, where he often
simplifies things beynd what would be scientifically acceptable, but a
reference in a journal or his textbook.

Thus spake Arnold Neumaier <Arnold.Neumaier@univie.ac.at
Oh No schrieb:

Thus any 'explanations' of what virtual particles do is meaningless.
You could as well ask how the person (virtual image) in the mirror
you are looking manages to move its hand when you lift your hand.

This is often asserted as though a definite fact, but it is actually
just a point of view,
It is the only correct point of view.

Please don't substitute dogmatism for logic in scientific argument.

There is no way to observe
virtual particles, and the name was chosen to reflect this.

At best this is semantically tautologous and of little worth.

Observed particles are always onshell, hence massless for photons,
whereas it is an easy exercise that the virtual photon mediating
electromagnetic interaction of two electrons in the tree approximation
is never onshell.

Again, that is a matter of semantics and definitional truism.

Energy is an empirical quantity and as such is strictly only meaningful in
measurement.

one to which Feynman himself did not subscribe. He
considered that we should not distinguish between real and virtual
particles.
Please give a reference, not from his writing for laymen, where he often
simplifies things beynd what would be scientifically acceptable, but a
reference in a journal or his textbook.

You denigrate Feynman.

He specifically states that he means his account
in QED to be scientifically correct. Are you calling him a liar for
saying that he sees no reason to distinguish? You may also refer to
Schweber, qed and the men who made it for confirmation that this was
Feynman's view.

Oh No schrieb:
Thus spake Arnold Neumaier <Arnold.Neumaier@univie.ac.at
Oh No schrieb:

Thus any 'explanations' of what virtual particles do is
meaningless.
You could as well ask how the person (virtual image) in the mirror
you are looking manages to move its hand when you lift your hand.

This is often asserted as though a definite fact, but it is actually
just a point of view,
It is the only correct point of view.
Please don't substitute dogmatism for logic in scientific argument.

I don't write only for you but for all readers of s.p.r.,
who can make their own judgment about the quality of my statements.
Calling my statement dogmatism doesn't diminish its truth.

I gave a scientific argument, which you apparently did not recognize,

and much more can be found in my theoretical physics FAQ at
http://www.mat.univie.ac.at/~neum/physics-faq.txt


There is no way to observe
virtual particles, and the name was chosen to reflect this.
At best this is semantically tautologous and of little worth.

It reflects the opinion of those who coined the notion.

Observed particles are always onshell, hence massless for photons,
whereas it is an easy exercise that the virtual photon mediating
electromagnetic interaction of two electrons in the tree approximation
is never onshell.
Again, that is a matter of semantics and definitional truism.

Yes, it is a matter of semantics (= meaning), which is on my side.
You can bend the words by redefining everything to your taste.
I don't have this choice since I want to represent objective knowledge,
so I use the words according to their best use.

Energy is an empirical quantity and as such is strictly only meaningful in
measurement.

Your usage of the word is completely off the mark.
Energy is also a theoretical quantity, and as such is meaningful
and of highest importance in most of theoretical physics.

Virtual particles, on the other hand, are _only_ a theoretical
quantity, without any empirical content.

Thus any 'explanations' of what virtual particles do is meaningless.
You could as well ask how the person (virtual image) in the mirror
you are looking manages to move its hand when you lift your hand.

On 6 Feb, 23:32, Arnold Neumaier <Arnold.Neuma...@univie.ac.at> wrote:

Thus any 'explanations' of what virtual particles do is meaningless.
You could as well ask how the person (virtual image) in the mirror
you are looking manages to move its hand when you lift your hand.

I don't think this analogon is quite appropriate: the crucial
difference is that the person in the mirror is never going to hit you
i.e. he doesn't have any physical impact whatsoever on the world. The
virtual particle in contrast is supposed to be associated with a very
real and measurable physical force. So in this sense, it appears
somewhat inconsistent to deny the reality of virtual particles.

Anyway, whether real or virtual, there is in my view a conceptual
problem with the idea of field quanta transmitting fundamental forces:
with this model, a fundamental force is effectively reduced to a
macroscopic force due to the interaction of the intermediating field
quanta with the particles, rather than an interaction between the
particles themselves. Not only this, but the concept doesn't actually
achieve what it is supposed to achieve (namely to eliminate the
concept of an action-at-a-distance) because now there is instead to
explain by means of which (very real) force the field quanta transmit
their momentum to the particle. In this respect, the whole concept
seems to be somewhat circular and thus inconsistent.

Thus spake Igor Khavkine <igor.kh@gmail.com

There are many points of view and yours maybe one of them, Feynman's may
be another, and mine a third. All of these points of view may be equally
valid and allowed to disagree when discussing physics informally.

Indeed. Ultimately a particular view may be shown to be correct, but
that is not the situation at the moment. I merely caution against
adopting a particular view as though it is established fact.

However, the same can no longer be said when we leave the informal realm
in favor of the quantitative and scientific one. Then, a physicist, that
considers the question "What is a virtual particle?" in earnest, will
not be able to find a definition that satisfies what is usually mean by
both "virtual" and "particle".

Finding answers to such questions is what I would regard as the object
of scientific research. One should not be too restrictive in this kind
of research. It may well be that what is usually meant by the word
"particle" does not correspond to anything in nature. For example, I
think that many people envisage a particle as a classical object which
has a position in space. But we do also discuss particles as quantum
objects. The usual definition of particle must be revised, but it does
not follow from that that no definition is possible.

[...] The paper in a Feynman diagram
is another matter. That really does have no physical meaning.

The very real and measurable physical force can be quite satisfactorily
described without reference to virtual particles.

Hence, whether you
consider virtual particles real has no bearing on the description on
measurements.

This may be subject of research, but not in physics. In physics, there
already is a definition of particle, both classically and quantum
mechanically.

Thus, the statement that a "virtual particle" is not a
particle is formal, true, and has already been given in precise language
in this discussion.

You may invent your own definition, but then you're no longer speaking
the same language as other physicists.