Quantum-geometric perspective on spin-orbit-coupled Bose superfluids


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Subasi A. L. , Iskin M.

PHYSICAL REVIEW A, vol.105, no.2, 2022 (Journal Indexed in SCI) identifier identifier identifier

  • Publication Type: Article / Article
  • Volume: 105 Issue: 2
  • Publication Date: 2022
  • Doi Number: 10.1103/physreva.105.023301
  • Title of Journal : PHYSICAL REVIEW A

Abstract

We employ the Bogoliubov approximation to study how the quantum geometry of the helicity states affects the superfluid properties of a spin-orbit-coupled Bose gas in continuum. In particular we derive the low-energy Bogoliubov spectrum for a plane-wave condensate in the lower helicity band and show that the geometric contributions to the sound velocity are distinguished by their linear dependences on the interaction strength; that is, they are in sharp contrast to the conventional contribution which has a square-root dependence. We also discuss the roton instability of the plane-wave condensate against the stripe phase and determine their phase-transition boundary. In addition we derive the superfluid density tensor by imposing a phase twist on the condensate order parameter and study the relative importance of its contribution from the interband processes that is related to the quantum geometry.