Lattice Unitarity: Saturated Collisional Resistivity in Hubbard Metals

TL;DR

This study explores the resistivity saturation in strongly interacting ultracold fermions within optical lattices, revealing a universal dissipation limit and temperature-dependent behavior.

Contribution

It provides the first experimental observation of resistivity saturation in a controlled atomic system, supported by a quantitative dissipation model using a renormalized scattering matrix.

Findings

Resistivity saturates at a universal value independent of interaction strength.

Temperature dependence of resistivity aligns with theoretical high-temperature predictions.

The results offer a microscopic understanding of resistivity bounds in low-density metals.

Abstract

We investigate the interaction-induced resistivity of ultracold fermions in a three-dimensional optical lattice. In situ observations of transport dynamics enable the determination of real and imaginary resistivity. In the strongly interacting metallic regime, we observe a striking saturation of the current-dissipation rate towards a value that is independent of the interaction strength. This phenomenon is quantitatively captured by a dissipation model that uses a renormalized two-body scattering matrix. We further measure the temperature dependence of resistivity in the strongly interacting limit and discuss the predicted asymptotic high-temperature behavior. Our results provide a clear microscopic understanding of bounded resistivity of low-density metals, thus providing a useful benchmark for studies of strongly correlated atomic and electronic systems.