5
$\begingroup$

I am trying to understand how photons as the force carrier for the electromagnetic force (or field) manifest themselves in a flow of electric charge, i.e. an electric current. Both standard (classical) model explanations and field explanations are welcome. I am a layman, so ... be gentle?

After doing some reading, research, digging, and crying, I keep returning to some explanations that seem to describe the photon's role best (but yet, I still think they might be inaccurate).

For instance, someone described it this way: electrons move through a wire in a line (direct current) because they are repelled by each other, thus they "push" each other down the wire. This pushing is expressed by photons (some say "virtual", i.e. mathematical not "real", photons) being exchanged between the electrons that "push" the electrons away from each other. Yet, if these (virtual?) photons push out in all directions, they would push against both electrons in the wire (for a simplified line of single electrons each having one in "front" and one "behind"). However, the dry cell (battery) reaction forcing electrons out one end and drawing them in at the other tips the balance, if you will, keeping the electrons moving in the direction of the current.

Alternately, I've heard it this way: a photon is a ripple in the photon field. The "ripple" is what we have been trying to (somewhat inaccurately) describe with the word "particle". As the photon moves, it interacts with (some say "creates") an electric field and a magnetic field (the electric and magnetic fields are perpendicular to each other). The photons that make up a static electric or magnetic field are virtual, i.e. their energy and momentum don't satisfy the conditions of "real" photons: E = p*c. Photons are emitted and absorbed by charged particles constantly. A charged particle is thus constantly emitting and absorbing virtual (i.e. mathematically described) photons. Photons only interact with charged particles, not with each other. Every photon is surrounded by a group/cadre/entourage of electrons (and other charged particles), through these associated charged particles, a photon can interact with another photon. Presumptively (and likely erroneously), the movement of these photons drives the electrons down our wire to complete the electric circuit and are thus responsible for the electric current.

Finally, there is this thing (which I love): https://www.youtube.com/watch?v=rxqZczaSA9c

... but what the heck is that? An electron constantly sucking in photons and spitting them about, but what are the four "rings" they are going through? Ripples in the electromagnetic field?

$\endgroup$
  • 1
    $\begingroup$ It sounds like your understanding is pretty good already. Just a couple things to keep in mind. (1) Always keep the quantum and classical pictures separate. A connection between them is not straightforward. For example, as you have pointed out, it is incorrect to say, "a photon interacts with an electromagnetic field". (2) Imagine a train running on tracks at a constant speed with no friction. Do it's cars push each other? No. And yet it keeps running in the initial direction. Do they push if it runs with friction? Yes, but relatively little. Same with electrons in the wire, no surprises. $\endgroup$ – safesphere May 29 '18 at 6:50
  • $\begingroup$ The youtube video you linked to has no scientific value whatsoever. Anyone can post a random animated picture and claim it represents some new theory. $\endgroup$ – Stéphane Rollandin May 29 '18 at 11:43

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Browse other questions tagged or ask your own question.