Multiple period states of the superfluid Fermi gas in an optical lattice

Abstract

We study multiple period states of a two-component unpolarized superfluid Fermi gas in an optical lattice along the Bardeen-Cooper-Schrieffer (BCS) to Bose-Einstein condensate (BEC) crossover. The existence of states whose period is a multiple of the lattice spacing is a direct consequence of the non-linear behavior of the gas, which is due to the presence of the order parameter associated with superfluidity. By solving Bogoliubov-de Gennes equations for a superfluid flow with finite quasimomentum, we find that, in the BCS side of the crossover, the multiple period states can be energetically favorable compared to the normal Bloch states and their survival time against dynamical instability drastically increases, suggesting that these states can be accessible in current experiments, in sharp contrast to the situation in BECs.

16 pages, 9 figures; to appear in New J. Phys

References in corpus (13)

• Many-Body Physics with Ultracold Gases
• Theory of ultracold Fermi gases
• Hysteresis in a quantized, superfluid atomtronic circuit
• Strongly paired fermions: Cold atoms and neutron matter
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• Formation of Nuclear "Pasta" in Supernovae
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• Critical velocity of superfluid flow through single barrier and periodic potentials
• Stable periodic density waves in dipolar Bose-Einstein condensates trapped in optical lattices
• Equation of state and effective mass of the unitary Fermi gas in a 1D periodic potential
• Swallowtail Band Structure of the Superfluid Fermi Gas in an Optical Lattice
• Effects of periodic potentials on the critical velocity of superfluid Fermi gases in the BCS-BEC crossover
• Aspects of Superfluid Cold Atomic Gases in Optical Lattices

Cited by in corpus (4)

• Nonlinear Phenomena of Ultracold Atomic Gases in Optical Lattices: Emergence of Novel Features in Extended States
• Attraction-induced dynamical stability of a Bose-Einstein condensate in a nonlinear lattice
• Stabilization of Nonlinear Lattices: A Route to Superfluidity and Hysteresis
• Stabilizing period-doubled density waves by spin-orbit coupling in Bose-Einstein condensates in optical lattices