Properties of the 3He A-B phase boundary

This thesis deals with various properties of the 3He A-8 phase boundary. First a review of some static properties, the surface energy and Kapitza resistance, is given. Then the symmetry of the interface is discussed. It is pointed out that, due to the presence of the condensate, many symmetries are broken. The effects of this are discussed; in par ticular it is shown that a transverse force acting across the boundary will result if a temperature difference exists between the two bulk phases. Finally the dynamics of the phase boundary is discussed via a phenomenological equation of motion. The higher temperature dissipative mechanism is ascribed to the Andreev scattering of excitations with the boundary. The predicted terminal velocity of the interface when the phases are hypercooled is shown to agree with experiment. The lower temperature dissipative mechanism is proposed to be pair-breaking, and a saturation of the terminal velocity at low temperatures is predicted.U of I OnlyThesi