# Collective excitations of a BCS superfluid in the presence of two sublattices

@article{Iskin2020CollectiveEO,
title={Collective excitations of a BCS superfluid in the presence of two sublattices},
author={M. Iskin},
journal={Physical Review A},
year={2020},
volume={101},
pages={053631}
}
• M. Iskin
• Published 1 January 2020
• Physics
• Physical Review A
We consider a generic Hamiltonian that is suitable for describing a uniform BCS superfluid on a lattice with a two-point basis and study its collective excitations at zero temperature. For this purpose, we first derive a Gaussian effective action for the pairing fluctuations and then extract the low-energy dispersion relations for the in-phase Goldstone and out-of-phase Leggett modes along with the corresponding amplitude (i.e., the so-called Higgs) ones. We find that while the Goldstone mode… Expand
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