Proposal for measuring the finite-temperature Drude weight of integrable systems

TL;DR

This paper proposes an experimental method using local quantum quenches in fermionic quantum-gas microscopes to measure the finite-temperature Drude weight and observe ballistic transport in integrable systems, revealing coexistence of transport channels.

Contribution

It introduces a concrete experimental proposal to measure finite-temperature Drude weights and observe ballistic transport in integrable quantum systems.

Findings

Proposal for local quench experiments to measure Drude weights

Connection established between local quenches and linear-response functions

Potential to observe coexistence of ballistic and diffusive transport

Abstract

Integrable models such as the spin-1/2 Heisenberg chain, the Lieb-Liniger or the one-dimensional Hubbard model are known to avoid thermalization, which was also demonstrated in several quantum-quench experiments. Another dramatic consequence of integrability is the zero-frequency anomaly in transport coefficients, which results in ballistic finite-temperature transport, despite the presence of strong interactions. While this aspect of nonergodic dynamics has been known for a long time, there has so far not been any unambiguous experimental realization thereof. We make a concrete proposal for the observation ballistic transport via local quantum quench experiments in fermionic quantum-gas microscopes. Such an experiment would also unveil the coexistence of ballistic and diffusive transport channels in one and the same system and provide a means of measuring finite-temperature Drude weights. The connection between local quenches and linear-response functions is established via time-dependent Einstein relations.