Acoustic Spectroscopy of Superfluid 3He in Aerogel
نویسندگان
چکیده
N. Mulders Department of Physics and Astronomy, University of Delaware, 223 Sharp Laboratory, Newark, Delaware 19716 (Received 21 December 1998) Liquid 3He in 98%-porous aerogel simultaneously possesses properties of a disordered p-wave superfluid and an elastic solid. We have observed two sound modes of superfluid 3He in aerogel. The first (fast) sound is a compression wave, and the second (slow) sound is the out-of-phase oscillation of the superfluid and the normal component that is coupled to the elastic aerogel matrix. A measurement of the slow sound velocity allows an accurate determination of the superfluid fraction. [S0031-9007(99)08991-7]
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