Hydrodynamic theory of supersolids: Variational principle and effective Lagrangian

Abstract

We develop an effective low-energy, long-wavelength theory of a bulk supersolid--a putative phase of matter with simultaneous crystallinity and Bose condensation. Using conservation laws and general symmetry arguments we derive an effective action that correctly describes the coupling between the Bose condensation and the elasticity of the solid. We use our effective action to calculate the correlation and response functions for the supersolid, and we show that the onset of supersolidity produces peaks in the response function, corresponding to propagating second sound modes in the solid. Throughout our work we make connections to existing work on effective theories of superfluids and normal solids, and we underscore the importance of conservation laws and symmetries in determining the number and character of the collective modes.

12 pages, 2 figures, submitted to PRB

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Cited by in corpus (21)

• Excitation spectrum of a supersolid
• Elementary excitations of ultracold soft-core bosons across the superfluid-supersolid phase transition
• Rotating a supersolid dipolar gas
• Supersolidity in ultra-cold dipolar gases
• Sound, superfluidity and layer compressibility in a ring dipolar supersolid
• Quantum hydrodynamics for supersolid crystals and quasicrystals
• Hydrodynamics of a superfluid smectic
• Excitations of a two-dimensional supersolid
• Decoupled sound and amplitude modes in trapped dipolar supersolids
• Excitations of a binary dipolar supersolid
• Observation of supersolid-like sound modes in a driven quantum gas
• Sounds waves and fluctuations in one-dimensional supersolids
• Classification of a supersolid: Trial wavefunctions, Symmetry breakings and Excitation spectra
• Quantum fluctuations in one-dimensional supersolids
• Supersolid spectroscopy
• Honeycomb supersolid -- Dirac points and shear-instability induced crystal transitions
• Anomalous dispersion of shear waves in dipolar supersolids
• Anomalous Doppler effect in superfluid and supersolid atomic gases
• Andreev-Lifshitz Hydrodynamics Applied to an Ordinary Solid under Pressure
• Andreev-Lifshitz Supersolid Hydrodynamics Including the Diffusive Mode
• Excitations and anisotropic sound in planar dipolar supersolids with tilted dipoles