Correlations within the Non-Equilibrium Green's Function Method

TL;DR

This paper explores how correlations are incorporated within the Non-equilibrium Green's Function method, demonstrating the evolution of quantum many-body systems and improving state preparation via adiabatic switching and cooling.

Contribution

It introduces a systematic way to include correlations in NGF for nuclear matter and finite systems, enhancing the understanding of their ground-state properties.

Findings

Correlations can be systematically incorporated in NGF.

Adiabatic switching combined with cooling improves state preparation.

Ground-state characteristics are achieved in nuclear matter models.

Abstract

Non-equilibrium Green's Function (NGF) method is a powerful tool for studying the evolution of quantum many-body systems. Different types of correlations can be systematically incorporated within the formalism. The time evolution of the single-particle Green's functions is described in terms of the Kadanoff-Baym equations. The current work initially focuses on introducing the correlations within infinite nuclear matter in one dimension and then in a finite system in the NGF approach. Starting from the harmonic oscillator Hamiltonian, by switching on adiabatically the mean-field and correlations simultaneously, a correlated state with ground-state characteristics is arrived at within the NGF method. Furthermore the use of cooling to for improving the adiabatic switching is explored.