Attractive force from gauge particle exchange

In summary, the conversation discusses the concept of photons as field quanta for the electromagnetic field and how their exchange can create both attractive and repulsive forces between particles. The concept of virtual particles is also mentioned, which are allowed to bend some rules that real particles must follow, and their effects can be observed experimentally. The conversation also touches on the oversimplification of popular physics articles and the idea that the Coulomb potential does not necessarily depend on virtual particles. A recommended resource for understanding virtual particles is A. Zee's book "Quantum field theory in a nutshell."
  • #1
tommybee
3
0
Photons are referred to as the field quanta for the electromagnetic field.

I would like to understand how the exchange of field quanta such as photons can create an attractive force.

For example, I can see that an electron could repel another electron by hitting it with photons. (radiation pressure ?)

How can the exchange of photons create an attractive force, though ?

For example, how does the exchange of photons cause the attraction of an electron to a proton ? If a proton emits photons that hit an electron, then Newton's third law would suggest that the electron and the proton should repel each other.

Please forgive my naivete if this type of simplistic "billiard ball" physics does no apply to elementary particles.
 
Physics news on Phys.org
  • #3
These are exchange of virtual particles. Virtual particles are allowed to bend some rules which real particles must follow. You can for instance have a photon moving in one direction with a momentum in a different direction.
 
  • #4
Thanks dauto,

I had read that these field quanta are virtual particles - distinct from standard photons, etc. I would appreciate a link or other reference that explains virtual particles without oversimplification. In this case the oversimplification of some popular physics articles has lead to misconceptions such as in my original question above.

Have these virtual photons been identified (observed) experimentally ?
 
  • #5
tommybee said:
Thanks dauto,

I had read that these field quanta are virtual particles - distinct from standard photons, etc. I would appreciate a link or other reference that explains virtual particles without oversimplification. In this case the oversimplification of some popular physics articles has lead to misconceptions such as in my original question above.

Have these virtual photons been identified (observed) experimentally ?

Virtual particles cannot be observed directly but their effects can. For instance the lamb shift ix explainable as a consequence of the emission and subsequent absorption of virtual photons.
 
  • #6
A simple explanation for the attractive force in QED works w/o virtual particles. A sketch of the general idea is

fix the gauge

##A_0=0##

solve Gauß law constraint

##\nabla E = \rho##

and replace the term

##A_0\,\rho##

in the Hamiltonian with the solution for the Gauß law:

##\int d^3x\,d^3y\,\frac{\rho(x)\,\rho(y)}{|x-y|}##

This shows that the Coulomb potential does not depend on "virtual particles.
 
  • #7
Maybe not explicitly, but it seems to me that the 1/|x-y| term is essentially the propagator of a virtual photon.
 
  • #8
If you like you can interpret it that way, but it's not necessary; all physical (transversal) photon d.o.f. contribute to other terms in the Hamiltonian
 
  • #9
I think A.Zee's book "Quantum field theory in a nutshell", gives a good explanation, just in the first chapter.
 

1. What is the concept of "attractive force from gauge particle exchange"?

The concept of "attractive force from gauge particle exchange" is a fundamental principle in particle physics. It states that particles interact with each other by exchanging virtual gauge particles, such as photons, gluons, or W and Z bosons. This exchange results in either an attractive or repulsive force between the particles, depending on the type of gauge particle exchanged.

2. How does the exchange of gauge particles lead to attractive forces?

In quantum field theory, particles are described as excitations of their corresponding fields. When two particles interact, they exchange virtual gauge particles, which act as carriers of the fundamental forces. These particles are constantly being created and destroyed, and their exchange between particles results in an attractive force, similar to how a magnet attracts a metal object due to the exchange of virtual photons.

3. Can you give an example of an attractive force from gauge particle exchange?

One of the most well-known examples of an attractive force from gauge particle exchange is the electromagnetic force. Two charged particles, such as electrons, repel each other due to the exchange of virtual photons. However, if one particle has a negative charge and the other has a positive charge, the exchange of virtual photons between them results in an attractive force that pulls the particles towards each other.

4. How does the strength of the attractive force depend on the exchange of gauge particles?

The strength of the attractive force between two particles depends on the type of gauge particle being exchanged. For example, the electromagnetic force is much stronger than the weak nuclear force, which is responsible for radioactive decay. This is because the exchange of virtual photons is more frequent and has a longer range than the exchange of virtual W and Z bosons.

5. What are the implications of the attractive force from gauge particle exchange in the field of particle physics?

The concept of attractive force from gauge particle exchange has significant implications in our understanding of the fundamental forces and interactions in the universe. It helps explain the behavior of particles at the subatomic level and is a crucial aspect of the Standard Model of particle physics. It also plays a role in the development of theories, such as quantum chromodynamics and electroweak theory, which aim to unify the fundamental forces.

Similar threads

  • High Energy, Nuclear, Particle Physics
Replies
12
Views
2K
  • High Energy, Nuclear, Particle Physics
Replies
22
Views
3K
  • High Energy, Nuclear, Particle Physics
Replies
6
Views
1K
  • High Energy, Nuclear, Particle Physics
Replies
1
Views
1K
  • High Energy, Nuclear, Particle Physics
Replies
4
Views
2K
  • High Energy, Nuclear, Particle Physics
Replies
6
Views
1K
  • High Energy, Nuclear, Particle Physics
Replies
17
Views
2K
  • High Energy, Nuclear, Particle Physics
Replies
11
Views
1K
  • High Energy, Nuclear, Particle Physics
Replies
21
Views
2K
  • High Energy, Nuclear, Particle Physics
Replies
1
Views
1K
Back
Top