A new sound mode in liquid Helium 4?

R. Schaefer; T. Fliessbach

doi:10.1016/0375-9601(94)90870-2

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A new sound mode in liquid Helium 4?

R. Schaefer·T. Fliessbach

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Abstract

This letter is based on the hypothesis of a small entropy content of the superfluid fraction of liquid helium. We show that such a superfluid entropy gives rise to a new sound mode in a ring-shaped superleak. This mode is named sixth sound. We propose an experiment by which its sound velocity and thereby the superfluid entropy can be measured. A negative experiment would yield a new upper limit for the superfluid entropy.

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R. Schaefer, T. Fliessbach. 1995-07-13. A new sound mode in liquid Helium 4?. https://doi.org/10.1016/0375-9601(94)90870-2

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