Static and Dynamic Critical Phenomena near the Superfluid Transition in 4He

Abstract

It is widely appreciated that the superfluid transition in liquid 4He is an exceptionally suitable system for detailed experimental investigations of continuous phase transitions. Its merits and limitations have been discussed in detail elsewhere, 1,2 and the experimental results on the static properties have been reviewed in detail.2 In the present lectures, I would like to provide a summary of some recent developments in our understanding of the static properties and then discuss the behavior of the singularities of transport properties. Before proceeding to this, however, it is useful to review recent more general developments not limited to the superfluid transition which pertain to the nature of confluent singularities. These singularities have a strong bearing on the interpretation of experimental results near phase transitions.