Superflow in Solid 4He

Abstract

Kim and Chan have recently observed Non-Classical Rotational Inertia (NCRI) for solid ${}^4$He in Vycor glass, gold film, and bulk. Their low $T$ value of the superfluid fraction, ${\rho }_s/\rho \approx 0.015$, is consistent with what is known of the atomic delocalization in this quantum solid. By including a lattice mass density ${\rho }_L$ distinct from the normal fluid density ${\rho }_n$, we argue that ${\rho }_s(T)\approx {\rho }_s(0)-{\rho }_n(T)$, and we develop a model for the normal fluid density ${\rho }_n$ with contributions from longitudinal phonons and ``defectons'' (which dominate). The Bose-Einstein Condensation (BEC) and macroscopic phase inferred from NCRI implies quantum vortex lines and quantum vortex rings, which may explain the unusually low critical velocity and certain hysteretic phenomena.

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References in corpus (2)

• Cold bosonic atoms in optical lattices
• Ring exchanges and the supersolid phase of 4He

Cited by in corpus (14)

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• Hydrodynamic theory of supersolids: Variational principle and effective Lagrangian
• Theory for supersolid ${}^4$He
• Bounds for the Superfluid Fraction from Exact Quantum Monte Carlo Local Densities
• Supersolid ${}^4$He Likely Has Nearly Isotropic Superflow
• Superfluidity versus localization in bulk 4He at zero temperature
• A Wave Function Describing Superfluidity in a Perfect Crystal
• Two-body correlations and the superfluid fraction for nonuniform systems
• Theory of Supersolids beyond Mean-Field
• Generation Efficiencies for Propagating Modes in a Supersolid
• Dynamics of Supersolid state: normal fluid, superfluid, and supersolid velocities