



01778nas a2200157   4500008004100000245006400041210006300105260001400168520129800182100001301480700002201493700001901515700002401534700002501558856003701583       2023                        eng d00aImproved Digital Quantum Simulation by Non-Unitary Channels0 aImproved Digital Quantum Simulation by NonUnitary Channels  c7/24/20233 a<p>Simulating quantum systems is one of the most promising avenues to harness the computational power of quantum computers. However, hardware errors in noisy near-term devices remain a major obstacle for applications. Ideas based on the randomization of Suzuki-Trotter product formulas have been shown to be a powerful approach to reducing the errors of quantum simulation and lowering the gate count. In this paper, we study the performance of non-unitary simulation channels and consider the error structure of channels constructed from a weighted average of unitary circuits. We show that averaging over just a few simulation circuits can significantly reduce the Trotterization error for both single-step short-time and multi-step long-time simulations. We focus our analysis on two approaches for constructing circuit ensembles for averaging: (i) permuting the order of the terms in the Hamiltonian and (ii) applying a set of global symmetry transformations. We compare our analytical error bounds to empirical performance and show that empirical error reduction surpasses our analytical estimates in most cases. Finally, we test our method on an IonQ trapped-ion quantum computer accessed via the Amazon Braket cloud platform, and benchmark the performance of the averaging approach.</p>1 aGong, W.1 aKharkov, Yaroslav1 aTran, Minh, C.1 aBienias, Przemyslaw1 aGorshkov, Alexey, V.  uhttps://arxiv.org/abs/2307.13028