Exciting the Higgs Mode in a Strongly Interacting Fermi Gas by Interaction Modulation

Phys Rev Lett. 2024 Oct 11;133(15):150403. doi: 10.1103/PhysRevLett.133.150403.

Abstract

We study the Higgs mode of a strongly interacting Fermi gas in the crossover regime between a fermionic and bosonic superfluid. By periodically modulating the interaction strength of the gas, we parametrically excite the Higgs mode and study its resonance frequency and line width as a function of both interaction strength and temperature. We find that the resonance frequency at low temperature agrees with a local-density approximation of the pairing gap. Both frequency and line width do not exhibit a pronounced variation with temperature, which is theoretically unexpected, however, in qualitative agreement with a different recent study.