Effects of quantum fluctuations on the low-energy collective modes of two-dimensional superfluid Fermi gases from the BCS to the Bose Limit
arXiv:2112.09232 · doi:10.1103/PhysRevLett.131.113001
Abstract
We investigate the effects of quantum fluctuations on the low-energy collective modes of two-dimensional (2D) -wave Fermi superfluids from the BCS to the Bose limit. We compare our results to recent Bragg scattering experiments in 2D box potentials, with very good agreement. We show that quantum fluctuations in the phase and modulus of the pairing order parameter are absolutely necessary to give physically acceptable chemical potential and dispersion relation of the low-energy collective mode throughout the BCS to Bose evolution. Furthermore, we demonstrate that the dispersion of the collective modes change from concave to convex as interactions are tuned from the BCS to the Bose regime, and never crosses the two-particle continuum, because arbitrarily small attractive interactions produce bound states in 2D.
7 pages, 4 figures; supplemental material with 5 pages, 1 figure
References in corpus (10)
- Superconductivity in single-layer films of FeSe with a transition temperature above 100 K
- Observation of a two-dimensional Fermi gas of atoms
- Observation of the Berezinskii-Kosterlitz-Thouless Phase Transition in an Ultracold Fermi Gas
- Crossover from 2D to 3D in a weakly interacting Fermi gas
- Phase structure, collective modes, and the axial anomaly in dense QCD
- Goldstone mode and pair-breaking excitations in atomic Fermi superfluids
- Spin-Imbalanced Quasi-Two-Dimensional Fermi Gases
- Excitation Spectrum and Superfluid Gap of an Ultracold Fermi Gas
- Direct observation of the Higgs amplitude mode in a two-dimensional quantum antiferromagnet near the quantum critical point
- Landau-Khalatnikov phonon damping in strongly interacting Fermi gases