Double occupancies in a disordered, atomic Mott insulator

Understanding the interplay between disorder and interactions in quantum systems is not only of fundamental interest but has practical relevance, such as in the field of materials engineering. A complete understanding for the combination of these ingredients remains elusive. We explore this problem in a new regime by trapping an ultracold strongly interacting atomic Bose gas in a 3D optical disordered lattice. We measure how the fraction of doubly occupied sites is affected by the addition of disorder and compare our observations to a simple site-decoupled model. By varying the entropy of the gas, the more complex problem of finite temperature is also investigated.