Study of Kosterlitz-Thouless Transition with Random Chemical Potential Using Quantum Monte Carlo Simulations

Disordered Bose systems have been investigated extensively theoretically and experimentally. While most studies are made for three-dimensional systems, we focus our studies on two-dimensional systems. In two-dimensional Bose systems, it is well-known that Kosterlitz-Thouless (KT) transition occurs. Our motivation is to investigate the effects of randomness on KT transition. The hardcore-Bose-Hubbard model with random chemical potential is investigated using quantum Monte Carlo simulations. Random distribution is assumed to obey the Gaussian distribution, and superfluid density and correlation functions are calculated. By changing the dispersion of the Gaussian distribution, we found that the transition temperature decreases as the dispersion increases. We obtained the phase diagram showing the superfluid (KT) phase and the disorder phase.