Simulating quantum transport with ultracold atoms and interaction effects

TL;DR

This paper extends ultracold atom simulations of quantum transport to multiple spin components, deriving a current formula, observing Fano resonances, and analyzing interaction effects on conductance in one-dimensional systems.

Contribution

It introduces a generalized scheme for simulating multi-spin quantum transport and derives a new current formula, also exploring interaction effects on conductance.

Findings

Fano resonance observed in two-spin conductance measurements.

Conductance vanishes with attractive interactions due to a spin gap.

Conductance is enhanced for repulsive interactions following a power law.

Abstract

Quantum transport can be simulated with ultracold atoms by employing spin superpositions of fermions interacting with spin-dependent potentials. Here we first extend this scheme to an arbitrary number of spin components so as to allow simulating transport through a multiterminal quantum dot and derive a current formula in terms of a spin rotation matrix and potential phase shifts. We then show that a Fano resonance manifests itself in measuring a linear conductance at zero temperature in the case of two spin components. We also study how a weak interparticle interaction in bulk affects quantum transport in one dimension with the bosonization and renormalization techniques. In particular, we find that the conductance vanishes for an attractive interaction due to a bulk spin gap, while it is enhanced for a repulsive interaction by a power law with lowering the temperature or the chemical potential difference.