QUASI-POSITRONIUM IN METALS

Abstract

A variational search is made for a quasi-bound state of an electron–positron pair in a metal. The basic equation used is the effective Schrödinger equation derived from the electron–positron propagator in an approximation which accurately accounts for the two-body correlations. It is found that no such state exists in metals and hence it can have no influence on the positron annihilation rates. However, the state appears for electron gases of sufficiently low density, [Formula: see text],* and thus determines the low-density annihilation rates.