PATH-INTEGRAL METHODS OF POSITRON-ANNIHILATION

The problem of computing the properties of a low mass quantum particle in equilibrium in a disordered medium is considered. with the advance ment of computational speed, statistical methods for sampling a comple x phase space are now viable. The Feynman-Kac path integral establishe s a connection between a quantum particle and classical polymer consis ting of p atoms. This allows the computation of quantum mechanical equ ilibrium values using well known methods devised for classical systems . Here we review the application of the path integral to the computati on the properties of thermalized positron and positronium and introduc e some new directions of investigation.