In electromagnetism the two particles interact due to exchange of photons.Can anyone explain this statement?

Question

In electromagnetism the two particles interact due to exchange of photons.Can anyone explain this statement?

Answer 1

its true

because electrons are quite far away from the protons and when the 2 particles interact , they become a single one by exchanging the protons.  

Answer 2

Charged particles interact via the electromagnetic field. In classical physics (non-quantum) the electromagnetic field can be described by the Maxwell equations. These equations explain the interaction of charged particles as well as the propagation of electromagnetic waves, e.g. light, radio waves, x-ray.

However, when it was discovered that electromagnetic waves have particles, i.e. photons, there was need for a new way to describe the electromagnetic field.

There are various ways of so called quantization. The Feynman path-integral is an early successful way to describe the electromagnetic interaction. The theory is called Quantum Electrodynamics (QED).

In this theory, every aspect of the electromagnetic field is described by photons. This is possible by the introduction of virtual photons.

Virtual particles are particles that are just introduced to do the math. You cannot observe virtual particles in experiment directly. To calculate the interaction of charged particles you would imagine all possible virtual photons (acting like real photons in the calculation) that can be exchanged by the particles, then you kind of sum up all the possibilities to get the probabilities of various outcomes of the experiment.

For example, say, two electrons meet, there is the possibility of electron 1 to emit a photon that will consequently be absorbed by electron 2. Another possibility is that electron 2 emits a photon that will be absorbed by electron 1. There is also the possibility, that the electrons will be swapped. An electron may emit a photon and absorb the same photon later. Each of these possibilities has a probability and a phase associated with. Say, you want to know the overall probability, for electron 1 to end up at place A and electron 2 to end up in place B, you would have to sum up all the amplitudes for all possible ways that this can be done. I cannot go into detail here. See the book source below for further information.

(Actually there is an infinite number of possibilities, but there are mathematical ways to sum up the most and neglect only those with very low probability.)

In quantum mechanics you cannot say what exactly happens in between setup and measurement of an experiment. Therefore we don't know whether the virtual particles exist. However, if you assume that there are virtual particles, you get the correct result.

So, I would rather say, the electromagnetic interaction is _described_ by the exchange of photons.

This may sound complicated, and in fact, if you want to get accurate results, the math IS quite complicated. However, to get a basic understanding of the concepts, just read R.P. Feynman's book “QED: The Strange Theory of Light and Matter”. It is illustrated and can be read without any understanding of mathematics.