Thermal conductivity of the one-dimensional Fermi-Hubbard model

TL;DR

This paper investigates the thermal conductivity of the one-dimensional Fermi-Hubbard model at finite temperature, revealing ballistic transport due to integrability and the effects of breaking it on energy diffusion.

Contribution

It provides detailed calculations of the thermal Drude weight's temperature and filling dependence, and explores how integrability breaking affects transport properties.

Findings

Ballistic thermal transport in the integrable model.

Vanishing Drude weights when integrability is broken.

Ballistic energy spread in local quenches with inhomogeneous energy profiles.

Abstract

We study the thermal conductivity of the one-dimensional Fermi-Hubbard model at finite temperature using a density matrix renormalization group approach. The integrability of this model gives rise to ballistic thermal transport. We calculate the temperature dependence of the thermal Drude weight at half filling for various interactions and moreover, we compute its filling dependence at infinite temperature. The finite-frequency contributions originating from the fact that the energy current is not a conserved quantity are investigated as well. We report evidence that breaking the integrability through a nearest-neighbor interaction leads to vanishing Drude weights and diffusive energy transport. Moreover, we demonstrate that energy spreads ballistically in local quenches with initially inhomogeneous energy density profiles in the integrable case. We discuss the relevance of our results for thermalization in ultra-cold quantum gas experiments and for transport measurements with quasi-one dimensional materials.