Propagation of first sound in liquid 3He

Abstract

The dispersion of first (hydrodynamic) sound in normalfluid and superfluid 3He has been measured in a cylindrical resonator at a pressure of 18.8 bar in the frequency range between 85 kHz and 227 kHz and in the temperature range between 1.2 and 50 mK. The sound velocity measured in the normalfluid regime confirms recent theories of the slip effect in Fermi liquids; in superfluid 3He-B we find qualitative agreement between experiment and theoretical sound velocity.