Energy Losses in a Many-Body System

Abstract

The energy loss problem is formulated in such a way as to include all losses simultaneously. The lifetime and energy losses of a particle in a well-defined single-particle state with small transition probability are found to be related to the self-energy operator. As an illustration of the application of the relation obtained, a derivation of the Bethe sum rule and the Čerenkov losses is given for a particle incident on a many-body system.