Quasiparticle motion in superfluidHe3and Kapitza resistance ofHe3A-Bphase boundary

Abstract

In this paper we investigate the motion of quasiparticles in superfluid ${}_{}{}^3{}_{}{}^{}\mathrm{He}$. The Bogoliubov–de Gennes equation is generalized to an arbitrary type of pairing. For the case of a unitary p-wave state, the ballistic description of Greaves and Leggett is shown to follow when the spatial variation of the order parameter is slow on the scale of a coherence length. We also investigate the equation of motion of the excitation spin in this case. We apply our equations to investigate the transport of energy across the ${}_{}{}^3{}_{}{}^{}\mathrm{He}$ A-B phase boundary, where in particular we show that a Kapitza resistance exists. The feasibility of measuring this resistance is discussed.