On melting of Boltzmann system of quantum hard spheres

Melting of a quantum system of hard spheres has been considered in the case when the effects of Bose and Fermi statistics can be neglected. It has been found that the quantum melting line always differs from the classical line with exception for T=0, P=0, where the both lines crossed. It is shown that the classical limit is not reachable at any finite temperatures.