Density Dependence of the Momentum Distribution forHe4

Abstract

Neutron-scattering techniques have been used to determine the momentum distribution $n\left(\overrightarrow{\mathrm{p}}\right)$ for ${}_{}{}^4{}_{}{}^{}\mathrm{He}$ for different temperatures and densities. $n\left(\overrightarrow{\mathrm{p}}\right)$ is found to be a strong function of density and thus brings into question any direct relationship between the condensate fraction and the pair distribution function $g(r,T)\mathrm{}$.