Ultimate Simulator Many body problems are difficult to model analytically and are often so complex that they cannot be simulated accurately on a classical computer. Because quantum systems can be inherently correlated, it has been proposed that such systems could be used to simulate other complex problems. Buluta and Nori (p. 108 ) review the progress being made toward realizing quantum simulators, describing some of the implementations and potential applications of using such controlled quantum systems as simulator tools.