Superfluidity of a Raman spin-orbit-coupled Bose gas at finite temperature

Abstract

We investigate the superfluidity of a three-dimensional weakly interacting Bose gas with a one-dimensional Raman-type spin-orbit coupling at both zero and finite temperatures. Using the imaginary-time Green's function within the Bogoliubov approximation, we explicitly derive analytic expressions of the current-current response functions in the plane-wave and zero-momentum phases, from which we extract the superfluid density in the limits of long wavelength and zero frequency. At zero temperature, we check that the resultant superfluid density agrees exactly with our previous analytic prediction obtained from a phase-twist approach. Both results also satisfy a generalized Josephson relation in the presence of spin-orbit coupling. At finite temperature, we find a significant non-monotonic temperature dependence of superfluid density near the transition from the plane-wave phase to the zero-momentum phase. We show that this non-trivial behavior might be understood from the sound velocity, which has a similar temperature dependence. The non-monotonic temperature dependence is also shared by Landau critical velocity, above which the spin-orbit-coupled Bose gas loses its superfluidity. Our results would be useful for further theoretical and experimental studies of superfluidity in exotic spin-orbit coupled quantum gases.

14 pages, 4 figures

References in corpus (14)

• Many-Body Physics with Ultracold Gases
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• Collective oscillations of a confined Bose gas at finite temperature in the random-phase approximation
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Cited by in corpus (5)

• Detection of roton and phonon excitations in a spin-orbit coupled Bose-Einstein condensate with a moving barrier
• Temperature-induced supersolidity in spin-orbit-coupled Bose gases
• Synthetic spin-orbit coupling for the multispin models in optical lattices
• Thermal amplification and melting of phases in spin-orbit-coupled spin-1 Bose-Einstein condensates
• Band-edge superfluid of Bose-Einstein condensates in the spin-orbit-coupled Zeeman lattice