Equation-of-motion approach to the critical dynamics of liquid helium at the lambda point

Abstract

A complete treatment of dynamic scaling in liquid helium at the lambda point is developed straightforwardly from explicit application of the nonlinear mode-coupling equations of motion, without Langevin noise terms. Special attention is given to the ratio w of the order-parameter and entropy relaxation rates. Various estimates indicate w = O(0.1), which produces a characteristic double-humped fluctuation spectrum, amenable to experimental verification. Further details are a thorough study of the transient solutions as well as the presentation of a new expansion scheme similar to the ɛ expansion but of superior accuracy.