The influence of F-wave pairing fluctuations on sound propagation in superfluid 3He-A

The theory of sound propagation in pair-correlated Fermi liquids developed previously by Wolfle, with additional F-wave pairing fluctuations, is applied to the ABM state. Expressions for the anisotropic sound absorption and velocity at arbitrary temperature and frequency in the collisionless limit are derived. The F-wave pairing fluctuations give a large effect on the normal-flapping mode frequency at low temperatures. The corresponding shift in the sound attenuation peak of this collective mode provides a sensitive probe of the F-wave pair coupling constant g3. There is also a pronounced effect on the super-flapping mode attenuation peak, which becomes well defined when F-wave pairing fluctuations are considered