charge ?

[1123581321]

I was wondering what gives particles charge in the first place - has it got to do with their quark constituents or something else..

 

or does it revolve around their interaction with external influence.. etc etc

[ajb]

To my mind the best explanation of what electric charge is the conserved quantity associated via Noether's theorem with the U(1) gauge symmetry of the theory.

 

Generally we have

 

[math]\textnormal{Symmetry} \longrightarrow \textnormal{Current conservation} \longrightarrow \textnormal{Conserved charge} [/math]

 

You can also think of the electric charge as the coupling parameter (or constant) between the particles and the electromagnetic field. This all comes down to a covariant derivative. In particular, in the presence of a U(1) gauge symmetry derivative becomes "modified" as

 

[math]\partial_{\mu} \rightarrow \partial_{\mu} - i e A_{\mu}[/math],

 

where [math]A_{\mu}[/math] is the electromagnetic field (or connection). The electric charge [math]e[/math] allows the electromagnetic field to couple with other fields, like the Dirac field describing the electron via the covariant derivative.

[alpha2cen]

Important thing is same charge particles repel each other. That makes every related equations.