Effect of texture on the propagation of collective modes in superfluid 3He

A phenomenological theory of collective modes in superfluid 3He-B, similar to the Leggett theory for spin dynamics, is developed. The theory can be applied to study the dynamics of collective modes in an inhomogeneous texture of the order parameter. In the presence of a magnetic field, the quantization axis of the angular momentum J that characterizes the modes varies in space in this texture. This results in a Van Hove-type texture-dependent singularity in the absorption spectrum of the ultrasound that excites the collective modes. Thus, in the texture produced by a magnetic field between parallel plates and observed with the aid of ultrasound, a collective mode with J = 2 should be split not into five modes, as it should in open geometry, but into ten. The additional splitting of the mode spectrum on account of the textures can be used to investigate vortex structures in a rotating superfluid liquid