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Title: Unbiased simulation of near-Clifford quantum circuits

Modeling and simulation are essential for predicting and verifying the behavior of fabricated quantum circuits, but existing simulation methods are either impractically costly or require an unrealistic simplification of error processes. In this paper, we present a method of simulating noisy Clifford circuits that is both accurate and practical in experimentally relevant regimes. In particular, the cost is weakly exponential in the size and the degree of non-Cliffordness of the circuit. Our approach is based on the construction of exact representations of quantum channels as quasiprobability distributions over stabilizer operations, which are then sampled, simulated, and weighted to yield unbiased statistical estimates of circuit outputs and other observables. As a demonstration of these techniques, we simulate a Steane [[7,1,3]]-encoded logical operation with non-Clifford errors and compute its fault tolerance error threshold. Finally, we expect that the method presented here will enable studies of much larger and more realistic quantum circuits than was previously possible.
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  1. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Quantum Computing Inst.
Publication Date:
Grant/Contract Number:
Accepted Manuscript
Journal Name:
Physical Review A
Additional Journal Information:
Journal Volume: 95; Journal Issue: 6; Journal ID: ISSN 2469-9926
American Physical Society (APS)
Research Org:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Sponsoring Org:
USDOE; Intelligence Advanced Research Projects Activity (IARPA) (United States)
Country of Publication:
United States
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; quantum algorithms; quantum computation; quantum simulation; quantum information
OSTI Identifier:
Alternate Identifier(s):
OSTI ID: 1367363; OSTI ID: 1399949