# Difference between a particle and its field

1. Jul 12, 2012

### San K

What is the difference between a field and a particle?
What is a field composed off?
Do weak and strong (nuclear) interactions have any fields associated with them?

Is the below correct (even if it does not answer the above questions):

A particle is an excitation of its field.

An electron is an excitation of the electronic field
A photon is an excitation of the EM field
A boson is an excitation of the Higg's field

2. Jul 12, 2012

### Mark M

What do you mean? A particle is a localized excitation of a field, whereas a field is a continuous entity that represents something at every point (such as a force).
Yes. The strong force is mediated by gluons, so the field that corresponds to it is the gluon field. The weak force is mediated by W and Z bosons. So, they are represented by a corresponding field. Since they are vector bosons, their field is a vector field.
Yes.
When talking about matter particles, the corresponding fields are called fermionic fields. An yes, there is one for every particle.
Yes.
No. A Higgs boson is an excitation of the Higgs field. Bosons are particles with integer spins, such as photons, gluons, etc.

3. Jul 12, 2012

### San K

Thanks Mark M

Agreed.

Typographical error, sorry. I forgot to write Higgs in front.

I wonder why it has to be that - a half-integer spin particle (Gluon/Boson) holds together a full integer spin particle (Quark/Fermion).

Could it be that you need (many) Gluons to occupy the same quantum state in order to hold the Quarks together?

4. Jul 12, 2012

### Mark M

Force carriers (gauge bosons) must be bosons so that they can appear to be continuous fields in the classical limit. For a simple example, think of the electromagnetic field. On a quantum level, we can think of a superposition of trillions of photons in the same state (the tensor product of their wavefunctions), but as we scale up to a macroscopic level, this appears to be a field in the classical sense. That's why you'll never come across a fermionic field - you can't have more than one fermion in the same state.