Polarized superfluidity in the attractive Hubbard model with population imbalance

Abstract

We study a two-component Fermi system with attractive interactions and different populations of the two species in a cubic lattice. For an intermediate coupling we find a uniformly polarized superfluid which is stable down to very low temperatures. The momentum distribution of this phase closely resembles that of the Sarma phase, characterized by two Fermi surfaces. This phase is shown to be stabilized by a potential energy gain, as in a BCS superfluid, in contrast to the unpolarized BEC which is stabilized by kinetic energy. We present general arguments suggesting that preformed pairs in the unpolarized superfluid favor the stabilization of a polarized superfluid phase.

4+ pages, 4 figures, new version

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Cited by in corpus (28)

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• Ultra-cold Polarized Fermi Gases
• Quantum Simulation of the Hubbard Model: The Attractive Route
• Quantum phase diagram of fermion mixtures with population imbalance in one-dimensional optical lattices
• Magnetism and domain formation in SU(3)-symmetric multi-species Fermi mixtures
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• Superfluid state in the periodic Anderson model with attractive interactions
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• Dimensional Crossover in a Spin-imbalanced Fermi gas
• Polarized superfluid state in a three-dimensional fermionic optical lattice
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