Finite temperature Drude weight of an integrable Bose chain

TL;DR

This paper investigates the finite temperature Drude weight of an integrable bosonic chain, revealing universal low-temperature behavior, confirming results with thermodynamic Bethe ansatz, and providing numerical analysis across temperature ranges.

Contribution

It introduces a comprehensive analysis of the finite temperature Drude weight in an integrable Bose chain, including universal low-temperature behavior and numerical results.

Findings

Low-temperature Drude weight is universal and described by a Gaussian model.

Thermodynamic Bethe ansatz confirms low-temperature results.

Numerical calculations of D(T) across temperature ranges.

Abstract

We study the Drude weight $D(T)$ at finite temperatures $T$ of an integrable bosonic model where the particles interact via nearest-neighbour coupling on a chain. At low temperatures, $D(T)$ is shown to be universal in the sense that this region is equivalently described by a Gaussian model. This low-temperature limit is also relevant for the integrable one-dimensional Bose gas. We then use the thermodynamic Bethe ansatz to confirm the low-temperature result, to obtain the high temperature limit of $D(T)$ and to calculate $D(T)$ numerically.