Collective Excitations of Rotating Dipolar Fermi Gases in the Fractional Quantum Hall Regime

TL;DR

This paper studies the collective excitations in rotating dipolar Fermi gases within the fractional quantum Hall regime, revealing a gapped spectrum with a roton minimum and signs of incipient crystallization.

Contribution

It applies magneto-roton theory to dipolar Fermi gases, providing new insights into their excitation spectrum and phase behavior in the fractional quantum Hall regime.

Findings

Finite energy gap in long wavelength limit

Deepened roton minimum near certain filling factors

Absence of low-lying single-particle excitations

Abstract

We apply the magneto-roton theory of the fractional quantum Hall effect to study the collective excitation spectrum of rotating dipolar Fermi gases. The predicted spectrum has a finite energy gap in the long wavelength limit and a roton minimum at finite wave vector. The roton minimum being deepened from filling factor 1/3 to filling factor 1/5 is a signature of incipient crystallization near filling factor 1/7. We also demonstrate that there are no low-lying single-particle excitations below the roton mode. The fractional-quantum-Hall fluid rotating dipolar fermions behaves as an incompressible superfluid at low temperature.