Real-time dynamics at finite temperature by DMRG: A path-integral approach

TL;DR

This paper introduces a path-integral DMRG method for calculating real-time correlation functions at finite temperatures, demonstrated on the XXZ-chain, showing accurate results within a certain time limit.

Contribution

The paper presents a novel path-integral approach integrated with DMRG to compute finite-temperature real-time dynamics, extending the capabilities of existing methods.

Findings

Accurate real-time correlation functions up to a spectrum-dependent time limit.

Validation against exact results at the free fermion point.

Effective for studying finite-temperature quantum dynamics.

Abstract

We propose a path-integral variant of the DMRG method to calculate real-time correlation functions at arbitrary finite temperatures. To illustrate the method we study the longitudinal autocorrelation function of the $XXZ$-chain. By comparison with exact results at the free fermion point we show that our method yields accurate results up to a limiting time which is determined by the spectrum of the reduced density matrix.