X1-111 (2015/10/30)
Approximate action for the interaction of charged particles
Particles are studied which interact only through the electromagnetic field of each other. For such particles, up to inverse square of the speed of light it is possible to write an effective action which includes only the particles (the fields are eliminated). A method is presented for calculating this action, which is based on boosting the system from a state in which one particle is at rest.