Gluon field
In theoretical particle physics, the gluon field is a four vector field characterizing the propagation of gluons in the strong interaction between quarks. It plays the same role in quantum chromodynamics as the electromagnetic four-potential in quantum electrodynamics - the gluon field constructs the gluon field strength tensor.
Throughout, Latin indices take values 1, 2, ..., 8 for the eight gluon color charges, while Greek indices take values 0 for timelike components and 1, 2, 3 for spacelike components of four-dimensional vectors and tensors in spacetime. Throughout all equations, the summation convention is used on all color and tensor indices, unless explicitly stated otherwise.
Gluons can have eight colour charges so there are eight fields, in contrast to photons which are neutral and so there is only one photon field.
The gluon fields for each color charge each have a "timelike" component analogous to the electric potential, and three "spacelike" components analogous to the magnetic vector potential. Using similar symbols:
where n = 1, 2, ... 8 are not exponents but enumerate the eight gluon color charges, and all components depend on the position vector r of the gluon and time t. Each is a scalar field, for some component of spacetime and gluon color charge.
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