CLASSICAL BEHAVIOR OF TWO-DIMENSIONAL LIQUID 3He NEAR A QUANTUM CRITICAL POINT

Non-Fermi-liquid (NFL) behavior of the specific heat C(T) of two-dimensional (2D) liquid He-3, first uncovered in measurements almost 20 years ago, is explained in terms of intrinsic properties of this system that emerge when its density rises and the liquid becomes strongly correlated. The occurrence of a T-independent beta term in C(T) is attributed to satisfaction of the conditions for Dulong-Petit behavior by the boson part of the free energy. This unexpected classicality stems from softening of the transverse zero-sound mode (TZSM) in the density region where the anomaly in C(T), associated with a quantum critical point (QCP), is observed.