Nonequilibrium Two-Particle Self-Consistent Approach

TL;DR

This paper extends the two-particle self-consistent (TPSC) approach to nonequilibrium conditions, enabling the study of time-dependent correlations and responses in interacting lattice systems beyond equilibrium.

Contribution

It introduces a nonequilibrium implementation of TPSC that accurately captures local and nonlocal correlations in higher-dimensional systems during dynamic processes.

Findings

Successfully computed time-dependent spin and charge response functions.

Analyzed the evolution of effective temperatures after interaction ramps.

Validated the approach in the two-dimensional Hubbard model.

Abstract

We present the nonequilibrium implementation of the two-particle self-consistent (TPSC) approach, which has been shown to provide a reliable equilibrium description of interacting lattice systems in the weak- and intermediate-correlation regime. This method captures the effects of local and nonlocal correlations in two- and higher-dimensional systems and satisfies the Mermin-Wagner theorem. We demonstrate the versatility of nonequilibrium TPSC with calculations of the time-dependent spin and charge response functions and the evolution of effective temperatures extracted from different correlation functions, after interaction ramps in the two-dimensional Hubbard model.