QUROPE Quantum Information Processing and Communication in Europe

Various quantum phenomena like high-Tc superconductivity or quark confinement are still awaiting universally accepted explanations, because of the computational complexity of solving simplified theoretical models designed to capture their relevant physics. Feynman suggested solving such models by "quantum simulation" with a device designed to obey the same quantum many-body dynamics. So far, the community has mostly focused on developing the \emph{controllability} of quantum simulators. Here, we discuss the necessity of analyzing the \emph{reliability} and \emph{efficiency} of such devices under disorder, noise and other imperfections. We illustrate our concerns with numerical simulations of a paradigmatic example - a disordered quantum spin chain - where we find that disorder can decrease the reliability of a quantum simulator, although large errors are introduced only for strong disorder.