Momentum Distribution of Normal and Superfluid Helium.

P. V. E. McClintock

John W. McWane

Paul E. Sokol, Ralph O. Simmons, D. L. Price +1 more

We have measured the momentum distributions in superfluid and normal Helium 4 at identical densities using inelastic neutron scattering as a function of temperature and density. At large enough momentum transfers Q the Impulse Approximation is valid and the single particle momentum distribution n(anti p) can be extracted from the inelastic scattering spectrum. Results are reported. (WHK)

David M. Ceperley, E. L. Pollock

Path-integral methods can be employed to calculate properties of boson systems at any temperature. We have performed a number of simulations of liquid helium and have calculated the momentum distribution as a function of temperature. We find that liquid helium has a condensate below 2 K but not above. The momentum distribution is found to be non-Gaussian even in normal liquid helium. We have also calculated the difference in the momentum distribution between a boson system and a distinguishable particle system.

George B. Hess

MANFRED L. RISTIG, P. M. Lam, J. W. Clark