Flow-Induced Charge Modulation in Superfluid Atomic Fermions Loaded into an Optical Kagome Lattice

TL;DR

This paper investigates how superflow in an optical kagome lattice induces charge density modulations in superfluid fermions, revealing a supersolid-like state with enhanced critical current and transition temperature, potentially observable experimentally.

Contribution

It demonstrates that superflow causes spatial modulations in superfluid density and order parameter in a kagome lattice, highlighting the role of lattice geometry and flatband effects.

Findings

Superflow induces charge density and order parameter modulations.

The superfluid state exhibits enhanced critical current and transition temperature.

The modulated superfluid state is experimentally realizable.

Abstract

We study the superfluid state of atomic fermions in a tunable optical kagome lattice motivated by recent experiments. We show that imposed superflow induces spatial modulations in the density and order parameter of the pair condensate and leads to a charge modulated superfluid state analogous to a supersolid state. The spatial modulations in the superfluid emerge due to the geometric effect of the kagome lattice that introduces anisotropy in hopping amplitudes of fermion pairs in the presence of superflow. We also study superflow instabilities and find that the critical current limited by the dynamical instability is quite enhanced due to the large density of states associated with the flatband. The charge modulated superfluid state can sustain high temperatures close to the transition temperature that is also enhanced due to the flatband, and is therefore realizable in experiments.