



01648nas a2200169   4500008004100000245006100041210006100102300001400163490000900177520116300186100002301349700001901372700001801391700001901409700001301428856003701441       2018                        eng d00aToward the first quantum simulation with quantum speedup0 aToward the first quantum simulation with quantum speedup  a9456-94610 v115 3 a<p><span style="color: rgb(51, 51, 51); font-family: &quot;Open Sans&quot;, HelveticaNeue, &quot;Helvetica Neue&quot;, Helvetica, Arial, sans-serif; font-size: 15px;">With quantum computers of significant size now on the horizon, we should understand how to best exploit their initially limited abilities. To this end, we aim to identify a practical problem that is beyond the reach of current classical computers, but that requires the fewest resources for a quantum computer. We consider quantum simulation of spin systems, which could be applied to understand condensed matter phenomena. We synthesize explicit circuits for three leading quantum simulation algorithms, using diverse techniques to tighten error bounds and optimize circuit implementations. Quantum signal processing appears to be preferred among algorithms with rigorous performance guarantees, whereas higher-order product formulas prevail if empirical error estimates suffice. Our circuits are orders of magnitude smaller than those for the simplest classically infeasible instances of factoring and quantum chemistry, bringing practical quantum computation closer to reality.</span></p>1 aChilds, Andrew, M.1 aMaslov, Dmitri1 aNam, Yunseong1 aRoss, Neil, J.1 aSu, Yuan  uhttps://arxiv.org/abs/1711.10980