Surface waves and bulk Ruderman mode of a bosonic superfluid vortex crystal in the lowest Landau level

Abstract

We determine and analyze collective normal modes of a finite disk-shaped two-dimensional vortex crystal formed in a compressible bosonic superfluid in an artificial magnetic field. Using the microscopic Gross-Pitaevskii theory in the lowest Landau level approximation, we generate vortex crystal ground states and solve the Bogoliubov-de Gennes equations for small amplitude collective oscillations. We find chiral surface waves that propagate at frequencies larger than those of the bulk Tkachenko modes. Furthermore, we study low frequency bulk excitations and identify a torsional Ruderman mode, which we find is well-described by a previously developed low-energy effective field theory.

13 pages, 9 figures, V2 contains an appendix discussing external potentials; a supplementary video is found on YouTube via https://youtu.be/hb0aN2aNNbQ

References in corpus (6)

• Many-Body Physics with Ultracold Gases
• Crystallization of Bosonic Quantum Hall States
• Bosonic superfluid on lowest Landau level
• Chiral Edge Modes in Helmholtz-Onsager Vortex Systems
• Two Nambu-Goldstone zero modes for rotating Bose-Einstein condensates
• Rayleigh waves and cyclotron surface modes of gyroscopic metamaterials

Cited by in corpus (5)

• Equatorial Waves in Rotating Bubble-Trapped Superfluids
• On quantum melting of superfluid vortex crystals: from Lifshitz scalar to dual gravity
• Rotating anisotropic Bose gas with large number of vortices
• Non-commutative effective field theory of the lowest Landau level superfluid
• Effective field theory for the superfluid vortex lattice from coset construction