Quantum Monte Carlo Study of a Positron in an Electron Gas

TL;DR

This paper uses Quantum Monte Carlo methods to study a positron in an electron gas, revealing smaller relaxation energies and unique momentum density features compared to previous predictions.

Contribution

It provides new Quantum Monte Carlo calculations of relaxation energy, pair-correlation, and momentum density for a positron in an electron gas, highlighting differences from earlier models.

Findings

Smaller relaxation energies in low-density regimes

Contact pair-correlation functions are reduced

Momentum densities show near-zero weight above Fermi momentum

Abstract

Quantum Monte Carlo calculations of the relaxation energy, pair-correlation function, and annihilating-pair momentum density are presented for a positron immersed in a homogeneous electron gas. We find smaller relaxation energies and contact pair-correlation functions in the important low-density regime than predicted by earlier studies. Our annihilating-pair momentum densities have almost zero weight above the Fermi momentum due to the cancellation of electron-electron and electron-positron correlation effects.