Monte Carlo Simulations of Hard-Core Bosons on a 3D Lattice

A model of hard-core bosons on a 3D lattice has been studied using both quantum Monte Carlo and classical Monte Carlo techniques. We have calculated the transition temperature for Bose--Einstein condensation, the zero temperature penetration depth and the specific heat critical amplitude, and have explored the hyperuniversal scaling relationship between these quantities pertaining to the expected 3D-XYcritical point. As a conclusion we draw a phenomenological analogy between the model studied and extreme type-II superconductors.