What is the force of attraction?

robert wrote:

Actually, force by the exchange of intermediate particles isn't as
classical as this. It's not really like two people tossing a basketball
back & forth. The wave functions of the particles must be taken into
account. A moving particle has a wave function which defines its
positional probability along the axis of travel. The whole function, a
wave packet, has a group velocity corresponding to the velocity of a
classical particle.

Let's say that a proton issues a photon. The group velocity of the
packet carries it to the neighborhood of an electron. But the photon's
wave function may extend well to the far side of the electron, and
there is some probability that the electron will interact with the
photon from that direction, rather than the direction from which the
wave group is coming. In that case, the electron aquires a negative
momentum contribution from the photon, and an increment of motion
towards the original proton.

-Mark Martin

> Actually, force by the exchange of intermediate particles isn't as

That's what I *meant* to say...

odin wrote:

Sure. I was speaking on your behalf. I am your Congressman. >

-Mark Martin

[Only registered users see links. ] wrote:

This is the correct answer, but it does beg an interesting question.
Where does this show up in the path integral?
That is, if I'm comparing e-e- and e-e+ scattering, I should see
somewhere in the first couple of orders of the perturbative expansion a
term or an interference between terms that the photon momentum that
dominates comes from different directions in the two cases. I've looked
for this and failed, and would appreciate it if someone who has found
this difference could point it out. Either a snippet of the calculation
or a reference to a text where the difference is calculated would
suffice.

PD

Thanks for the reply. One question though - if the photon has a probability
of interacting with the proton from either side, why do we never see a
proton being repelled by an electron - why does the photon from the
"positive" source always interact with the negatively charged particle from
the "other side" to make the force an attractive one? Shouldn't it be 50-50
on which side of the proton the photon's probability wave collapses?



<[Only registered users see links. ]> wrote in message
news:1132096867.393108.218460@g14g2000cwa.googlegr oups.com...

robert wrote:

That's a very good question, and that's effectively what PD is
asking in relation to this issue. As it turns out, I've found a pretty
interesting page that interprets electric charge signs and the
difference between repulsive & attractive forces as the difference
between the direction of time in quantum mechanical interactions.

[Only registered users see links. ]

-Mark Martin