Competing many-body instabilities in two-dimensional dipolar Fermi gases

TL;DR

This paper develops a comprehensive theoretical framework to analyze competing many-body phases in two-dimensional dipolar Fermi gases, revealing a density wave phase at certain conditions and clarifying the phase diagram.

Contribution

It introduces a unified approach using functional renormalization-group equations to treat all instabilities simultaneously, providing a clearer phase diagram.

Findings

Density wave phase at small tilting angles and strong interactions

No evidence found for the supersolid phase

Estimated critical temperatures for ordered phases

Abstract

Experiments on quantum degenerate Fermi gases of magnetic atoms and dipolar molecules begin to probe their broken symmetry phases dominated by the long-range, anisotropic dipole-dipole interaction. Several candidate phases including the p-wave superfluid, the stripe density wave, and a supersolid have been proposed theoretically for two-dimensional spinless dipolar Fermi gases. Yet the phase boundaries predicted by different approximations vary greatly, and a definitive phase diagram is still lacking. Here we present a theory that treats all competing many-body instabilities in the particle-particle and particle-hole channel on equal footing. We obtain the low temperature phase diagram by numerically solving the functional renormalization-group flow equations and find a nontrivial density wave phase at small dipolar tilting angles and strong interactions, but no evidence of the supersolid phase. We also estimate the critical temperatures of the ordered phases.