Diffusive charge transport in the gapped 1D Hubbard model at all finite temperatures

TL;DR

This paper demonstrates that charge transport in the gapped 1D Hubbard model is normal diffusive at all finite temperatures, challenging previous hydrodynamic and KPZ scaling predictions of superdiffusive behavior.

Contribution

It identifies mechanisms explaining the temperature dependence of spin and charge transport, showing charge transport is normal diffusive at all finite temperatures.

Findings

Charge transport is normal diffusive at all finite T.

Contradicts hydrodynamic and KPZ predictions of superdiffusion.

Provides mechanisms for temperature-dependent transport behavior.

Abstract

Studies relying on hydrodynamic theory and Kardar-Parisi-Zhang (KPZ) scaling have found that in the one-dimensional Hubbard model spin and charge transport are for all temperatures T > 0 anomalous superdiffusive at zero magnetic field, h = 0, and zero chemical potential, {\mu} = 0, respectively. However, this contradicts recent exact results that at very low temperature charge transport rather is normal diffusive. In this Letter we identify the mechanisms that control the different types of temperature dependence of the h = 0 spin and {\mu} = 0 charge transport and find that the latter is normal diffusive for all finite temperatures T > 0, in contrast to the hydrodynamic theory and KPZ scaling predictions.