Abstract
We investigate the superfluid (SF) to Bose-glass (BG) quantum phase transition using extensive quantum Monte Carlo simulations of two-dimensional hard-core bosons in a random box potential. critical properties are studied by thorough finite-size scaling of condensate and SF densities, both vanishing at the same critical disorder . Our results give the following estimates for the critical exponents: , , . Furthermore, the probability distribution of the SF response displays striking differences across the transition: while it narrows with increasing system sizes in the SF phase, it broadens in the BG regime, indicating an absence of self-averaging, and at the critical point is scale invariant. Finally, high-precision measurements of the local density rule out a percolation picture for the SF-BG transition.
- Received 16 January 2015
DOI:https://doi.org/10.1103/PhysRevLett.114.155301
© 2015 American Physical Society