Self‐Consistent Scheme for Evaluating the Pressure Dependent Zero‐Sound Velocity in Normal Liquid 3 He

Using the theoretical model developed recently for liquid 3 He, the pressure dependent zero‐sound velocities at T = 0 K are calculated by a self‐consistent procedure. Introducing a pseudopotential for the effective interaction between two 3 He atoms of parallel and antiparallel spin, reasonable agreement with the experimental data of Wheatley et al. is found. An exact agreement with the experimental value is obtained by introducing a term into the theory to account for the local field corrections to the bare particle‐hole propagator beyond the random phase approximation (RPA) in a parametric way. The present theory seems to indicate the propagation of a new kind of sound wave in liquid 3 He.