Ab initio transport results for strongly correlated fermions

TL;DR

This paper presents first-principles nonequilibrium Green function calculations for strongly correlated fermions in Hubbard clusters, revealing universal scaling laws that match experimental cold atom diffusion results.

Contribution

It introduces a novel ab initio approach using T-matrix selfenergies for finite Hubbard clusters and demonstrates universal scaling applicable to infinite systems.

Findings

Universal scaling law for expansion dynamics

Excellent agreement with cold atom experiments

Predicts dependence on interaction strength and particle number

Abstract

Quantum transport of strongly correlated fermions is of central interest in condensed matter physics. Here, we present first-principle nonequilibrium Green functions results using $T$-matrix selfenergies for finite Hubbard clusters of dimension $1,2,3$. We compute the expansion dynamics following a potential quench and predict its dependence on the interaction strength and particle number. We discover a universal scaling, allowing an extrapolation to infinite-size systems, which shows excellent agreement with recent cold atom diffusion experiments [Schneider et al., Nat. Phys. 8, 213 (2012)].