Quadratic response theory for the interaction of charged particles with an electron gas

TL;DR

This paper reviews quadratic response theories within many-body perturbation theory to understand nonlinear interactions of charged particles with an electron gas, focusing on stopping power and plasmon excitations.

Contribution

It provides a comprehensive survey of quadratic response theories applied to charged particle interactions in an electron gas, emphasizing nonlinear effects and plasmon contributions.

Findings

Nonlinear corrections significantly affect stopping power calculations.

Double plasmon excitations contribute notably to energy loss.

Mean free paths for double plasmon excitations are characterized.

Abstract

A survey is presented of the theoretical status of quadratic response theories for the understanding of nonlinear aspects in the interaction of charged particles with matter. In the frame of the many-body perturbation theory we study the interaction of charged particles with the electron gas, within the random-phase approximation (RPA). In particular, nonlinear corrections to the stopping power of an electron gas for ions are analyzed, and special emphasis is made on the contribution to the stopping power coming from the excitation of single and double plasmons. Double plasmon mean free paths of swift electrons passing through an electron gas are also discussed.