Properties of a Possible Superfluid State of ³He

Abstract

RECENT results by Osheroff et al.^1,2 on anomalies in the pressure-temperature relation and n.m.r. line of ³He along the melting curve have stimulated us to consider the possibility that the much discussed^3–7 anisotropic superfluid condensation of liquid ³He may in fact be occurring. Briefly these results are: first, as the volume is varied continuously in time, the curve of pressure against time exhibits a discontinuous slope at a point labelled A and a “glitch” at a point B, the slope before and after the “glitch” remaining about the same. Second, at point A the n.m.r. line starts shifting to higher frequencies until point B; it then returns to its unshifted value, but with a reduced intensity. The temperature at point A is estimated to be about 3 mK and at point B about 2 mK. If, as the nuclear resonance results show, the first anomaly is associated with the liquid, point A can be interpreted in terms of a second order phase transition in the liquid and point B, which also shows hysteresis effects, as a first order transition.