Unbiased simulation of nearClifford 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 nonCliffordness 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 nonClifford 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.
 Authors:

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 Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Quantum Computing Inst.
 Publication Date:
 Grant/Contract Number:
 AC0500OR22725
 Type:
 Accepted Manuscript
 Journal Name:
 Physical Review A
 Additional Journal Information:
 Journal Volume: 95; Journal Issue: 6; Journal ID: ISSN 24699926
 Publisher:
 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
 Language:
 English
 Subject:
 71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; quantum algorithms; quantum computation; quantum simulation; quantum information
 OSTI Identifier:
 1376419
 Alternate Identifier(s):
 OSTI ID: 1367363; OSTI ID: 1399949
Bennink, Ryan S., Ferragut, Erik M., Humble, Travis S., Laska, Jason A., Nutaro, James J., Pleszkoch, Mark G., and Pooser, Raphael C.. Unbiased simulation of nearClifford quantum circuits. United States: N. p.,
Web. doi:10.1103/PhysRevA.95.062337.
Bennink, Ryan S., Ferragut, Erik M., Humble, Travis S., Laska, Jason A., Nutaro, James J., Pleszkoch, Mark G., & Pooser, Raphael C.. Unbiased simulation of nearClifford quantum circuits. United States. doi:10.1103/PhysRevA.95.062337.
Bennink, Ryan S., Ferragut, Erik M., Humble, Travis S., Laska, Jason A., Nutaro, James J., Pleszkoch, Mark G., and Pooser, Raphael C.. 2017.
"Unbiased simulation of nearClifford quantum circuits". United States.
doi:10.1103/PhysRevA.95.062337. https://www.osti.gov/servlets/purl/1376419.
@article{osti_1376419,
title = {Unbiased simulation of nearClifford quantum circuits},
author = {Bennink, Ryan S. and Ferragut, Erik M. and Humble, Travis S. and Laska, Jason A. and Nutaro, James J. and Pleszkoch, Mark G. and Pooser, Raphael C.},
abstractNote = {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 nonCliffordness 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 nonClifford 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.},
doi = {10.1103/PhysRevA.95.062337},
journal = {Physical Review A},
number = 6,
volume = 95,
place = {United States},
year = {2017},
month = {6}
}