Dissipation mechanisms near the superfluid3He transition in aerogel

The dissipation mechanisms (Q-1) near the superfluid 3He transition in aerogel was investigated using the torsion pendulum technique. It was found that with pure 3He the Q-1 decerases at the onset of superfluidity. It was also found that when phase separated 3He-4He mixtures are introduced into the aerogel, the Q-1 does not decrease as rapidly and eventually increases for the highest 4He content. A model for the related attenuation of transverse sound α that takes into account elastic and inelastic scattering processes was also presented.