Wigner function quantum molecular dynamics

TL;DR

This paper explores extending classical molecular dynamics to quantum systems using Wigner functions, addressing challenges in wave packet methods and proposing a general alternative approach for simulating quantum many-body systems.

Contribution

It introduces a novel quantum molecular dynamics method based on Wigner functions, overcoming limitations of wave packet approaches for unbound electrons in gases and plasmas.

Findings

Developed a general framework for quantum molecular dynamics using Wigner functions.

Identified limitations of wave packet methods in describing strong interactions.

Proposed an alternative approach to simulate quantum many-body systems effectively.

Abstract

Classical molecular dynamics (MD) is a well established and powerful tool in various fields of science, e.g. chemistry, plasma physics, cluster physics and condensed matter physics. Objects of investigation are few-body systems and many-body systems as well. The broadness and level of sophistication of this technique is documented in many monographs and reviews, see for example \cite{Allan,Frenkel,mdhere}. Here we discuss the extension of MD to quantum systems (QMD). There have been many attempts in this direction which differ from one another, depending on the type of system under consideration. One direction of QMD has been developed for condensed matter systems and will not discussed here, e.g. \cite{fermid}. In this chapter we are dealing with unbound electrons as they occur in gases, fluids or plasmas. Here, one strategy is to replace classical point particles by wave packets, e.g. \cite{fermid,KTR94,zwicknagel06} which is quite successful. At the same time, this method struggles with problems related to the dispersion of such a packet and difficulties to properly describe strong electron-ion interaction and bound state formation. We, therefore, avoid such restrictions and consider a completely general alternative approach. We start discussion of quantum dynamics from a general consideration of quantum distribution functions.