Beyond the Landau Criterion for Superfluidity

Abstract

According to the Landau criterion for superfluidity, a Bose-Einstein condensate flowing with a group velocity smaller than the sound velocity is energetically stable to the presence of perturbing potentials. We found that this is strictly correct only for vanishingly small perturbations. The superfluid critical velocity strongly depends on the strength and shape of the defect. We quantitatively study, both numerically and with an approximate analytical model, the dynamical response of a one-dimensional condensate flowing against an istantaneously raised spatially periodic defect. We found that the critical velocity $v_c$ decreases by incresing the strength of the defect $V_0$, up to to a critical value of the defect intensity where the critical velocity vanishes.

References in corpus (16)

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Cited by in corpus (15)

• Ultra-Light Dark Matter
• Stationary and non-stationary fluid flow of a Bose-Einstein condensate through a penetrable barrier
• Critical velocity for superfluid flow across the BEC-BCS crossover
• Bogoliubov-Cerenkov radiation in a Bose-Einstein condensate flowing against an obstacle
• Anisotropic superfluidity in a dipolar Bose gas
• Critical superfluid velocity in a trapped dipolar gas
• Superflow of resonantly driven polaritons against a defect
• Backscattering suppression in supersonic 1D polariton condensates
• Drag in a resonantly driven polariton fluid
• Superfluidity of the BEC at finite temperature
• Stationary states of Bose-Einstein condensed atoms rotating in an asymmetric ring potential
• Probing quantum transport by engineering correlations in a speckle potential
• Localization of an inhomogeneous Bose-Einstein condensate in a moving random potential
• Superfluids in Polymer Quantum Mechanics
• Optical Lattices: Theory