Communications on Applied Mathematics and Computation ›› 2025, Vol. 7 ›› Issue (2): 442-469.doi: 10.1007/s42967-023-00336-z

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A Partially Random Trotter Algorithm for Quantum Hamiltonian Simulations

Shi Jin1, Xiantao Li2   

  1. 1 School of Mathematical Sciences, Institute of Natural Sciences, MOE-LSEC and SHL-MAC, Shanghai Jiao Tong University, Shanghai 200240, China;
    2 Department of Mathematics, Pennsylvania State University, University Park, State College, PA 16802, USA
  • Received:2023-04-21 Revised:2023-09-29 Accepted:2023-10-03 Online:2025-06-20 Published:2025-04-21
  • Supported by:
    Jin’s research was supported by the NSFC (Grant No. 12031013) and the Innovation Program of Shanghai Municipal Education Commission (Nos. 2021-01-07-00-02-E00087). Li’s research has been supported by the NSF (Grant Nos. DMS-1953120 and DMS-2111221).

Abstract: Given the Hamiltonian, the evaluation of unitary operators has been at the heart of many quantum algorithms. Motivated by existing deterministic and random methods, we present a hybrid approach, where Hamiltonians with large amplitude are evaluated at each time step, while the remaining terms are evaluated at random. The bound for the mean square error is obtained, together with a concentration bound. The mean square error consists of a variance term and a bias term, arising, respectively, from the random sampling of the Hamiltonian terms and the operator-splitting error. Leveraging on the bias/variance tradeoff, the error can be minimized by balancing the two. The concentration bound provides an estimate of the number of gates. The estimates are verified using numerical experiments on classical computers.

Key words: Trotter splitting, Quantum simulation, Unitary dynamics

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