KINETIC-ENERGY OF LIQUID AND SOLID HE-4

We report new path-integral calculations and measurements of the kinet ic energy of condensed helium and construct an overall dependence of k inetic energy on temperature for densities less than 70 atoms nm(-3). In the solid phase we find the kinetic energy is almost temperature in dependent and, surprisingly, has a smaller kinetic energy than the flu id near freezing at the same density. In the high temperature fluid ph ase, the excess kinetic energy decreases to zero very slowly because o f pair scattering from the repulsive interatomic potential.