QUANTUM AND CLASSICAL BEHAVIOR OF SINGLE-PARTICLE DYNAMICS IN DENSE LIQUID-HE-4

Inelastic-neutron-scattering measurements at high exchanged momentum have been performed in fluid He4 along a supercritical isochore in the 4.2-50 K temperature range. The data have been analyzed in the plane-wave impulse approximation to obtain the root-mean-square values of the particle momentum. Deviations from classical behavior have been interpreted as arising from the quantum nature of the particle oscillations in the framework of a cell model for the fluid. © 1994 The American Physical Society.