Pairing and vortex lattices for interacting fermions in optical lattices with a large magnetic field.
We study the structure of a pairing order parameter for spin-1/2 fermions with attractive interactions in a square lattice under a uniform magnetic field. Because the magnetic translation symmetry gives a unique degeneracy in the single-particle spectrum, the pair wave function has both zero and finite-momentum components coexisting, and their relative phases are determined by a self-consistent mean-field theory. We present a microscopic calculation that can determine the vortex lattice structure in the superfluid phase for different flux densities. Phase transition from a Hofstadter insulator to a superfluid phase is also discussed.
Zhai
Hui
H
Institute for Advanced Study, Tsinghua University, Beijing, 100084, China. hzhai@mail.tsinghua.edu.cn
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