Localization in interacting, disordered, Bose systems

We use quantum Monte Carlo techniques to study a one-dimensional, disordered, interacting, Bose Hamiltonian. The effect of disorder on the Mott-insulator portion of the phase diagram is determined. We observe the destruction of superfluidity by disorder at incommensurate densities, for the first time demonstrating the emergence of a ``Bose-glass'' phase. In addition to these strong-coupling phases, we observe an unanticipated re-entrance into an Anderson-type localized regime for weak couplings.