On the properties of the four-momentum of an isolated charge + field system

Resumo

The question of the isolation of a charged particle along with its field such that the four-momentum of an entire system is a four-vector is raised. The relationships between the characteristics of a particle and a field upon such isolation have been obtained. In particular, it has been demonstrated that within the considered nonclassical models the particle mass should be greater than one-third of the field mass.