Ultracold atom quantum simulators pass first key test

Ultracold atoms trapped by laser beams make artificial materials which can be engineered with a remarkable level of control and tunability. They provide a unique toolbox for emulating the prototypical models of condensed matter physics. Before they can be trusted as quantum simulators, they need to be checked and validated against known results, for which quantum Monte Carlo simulations are ideally suited. I will give an overview of recent studies on ultracold bosonic and fermionic systems in an optical lattice, starting with time-of-flight interference patterns and single site resolution techniques for bosons. I will proceed with recent progress for fermionic systems, before addressing the open questions and conclusions.