Light front quantization

In theoretical physics, light front quantization refers to a specific choice of the initial degrees of freedom i.e. canonical coordinates and their momenta. While the usual option in field theory is to determine their value at a particular value of time, $t=x^0$, light cone quantization is based on null slices and the initial conditions are determined by the values of all fields at a constant value of $x^+\; =\; x^0+x^3$. The equal-time slice is a light-like hypersurface.

See also light cone gauge (that is usually imposed simultaneously).