Metastable Thermodynamic States Near the Critical Point ofHe3

Abstract

We report the first measurements of the specific heat of a metastable, superheated, pure liquid (${\mathrm{He}}^3$). The specific heat shows no evidence of any singularity near the onset of metastability. We have also observed the lifetimes of metastable states as the ${\mathrm{He}}^3$ is cooled at constant density. For densities near the critical density, lifetimes decrease abruptly in an extremely narrow, reproducible temperature interval. This may indicate the onset of an "intrinsic" instability.