Conductivity of quantum-spin chains: A Quantum Monte Carlo approach

TL;DR

This paper uses Quantum Monte Carlo methods to analyze the transport properties of spin-1/2 chains, distinguishing between ballistic and diffusive behaviors and calculating key transport parameters.

Contribution

It introduces a careful analysis technique of QMC data to differentiate transport types and provides detailed transport coefficients for both integrable and non-integrable quantum-spin chains.

Findings

Quantum Monte Carlo can distinguish ballistic from diffusive transport.

Drude weight, relaxation time, and mean-free path are computed for different chains.

Phenomenological relations between transport and thermal response are discussed.

Abstract

We discuss zero-frequency transport properties of various spin-1/2 chains. We show, that a careful analysis of Quantum Monte-Carlo (QMC) data on the imaginary axis allows to distinguish between intrinsic ballistic and diffusive transport. We determine the Drude weight, current-relaxation life-time and the mean-free path for integrable and a non-integrable quantum-spin chain. We discuss, in addition, some phenomenological relations between various transport-coefficients and thermal response functions.