Collision Drag Effect on Propagation of Sound in Liquid ${}^3$He in Aerogel

Abstract

Sound propagation in a Fermi liquid with impurities is studied using the Landau-Boltzmann equation and the result is compared with a recent experiment in liquid ${}^3$He in aerogel by Northwestern University group. The sound absorption calculated using the fixed impurity model is a few orders of magnitude larger than the experiment. We take into account the simultaneous motion of aerogel molecules and propose a model in which the momentum loss of ${}^3$He quasi-particles during the collisions with the aerogel is converted to a drag force that acts on the aerogel molecules. This collision drag model gives a reasonable description for the temperature and the pressure dependence of observed sound velocity and absorption.

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References in corpus (1)

• Magnetic Susceptibility of the Balian-Werthamer Phase of 3He in Aerogel

Cited by in corpus (5)

• Ultrasound attenuation of superfluid ${}^3$He in aerogel
• Porosity dependence of sound propagation in liquid ${}^4$He filled aerogel
• Collision Drag Effect on Two-Fluid Hydrodynamics of Superfluid 3He in Aerogel
• Knudsen-to-Hydrodynamic Crossover in Liquid 3He in a High-Porosity Aerogel
• Proposal to Observe Transverse Sound in Normal Liquid ${}^3$He in Aerogel