Topological superradiance in a degenerate Fermi gas

TL;DR

This paper predicts a novel topological superradiant phase in a degenerate Fermi gas within a cavity, driven by cavity-induced spin-orbit coupling, leading to a topological phase transition detectable via momentum-space signatures.

Contribution

It introduces the concept of topological superradiance in a Fermi gas and maps its phase diagram, revealing a critical point and methods for experimental detection.

Findings

Existence of a topological superradiant phase in a Fermi gas.

Identification of a critical quadracritical point separating phase boundaries.

Proposed detection method via momentum-space density distribution.

Abstract

We predict the existence of a topological superradiant state in a two-component degenerate Fermi gas in a cavity. The superradiant light generation in the transversely driven cavity mode induces a cavity-assisted spin-orbit coupling in the system and opens a bulk gap at half-filling. This mechanism can simultaneously drive a topological phase transition in the system, yielding a topological superradiant phase. We map out the steady-state phase diagram of the system in the presence of an effective Zeeman field, and identify a critical quadracritical point beyond which the topological and the conventional superraidiant phase boundaries separate. We also propose to detect the topological phase transitions based on the unique signatures in the momentum-space density distribution.