Low-cost error mitigation by symmetry verification

Journal article (2018)

Authors

X. Bonet Monroig Universiteit Leiden
R.E. Sagastizabal QuTech Advanced Research Centre, Kavli institute of nanoscience Delft, QCD/DiCarlo Lab - QuTech Advanced Research Centre
M Singh ImPhys/Optics - AS , Kavli institute of nanoscience Delft, QuTech Advanced Research Centre
T.E. O'Brien Universiteit Leiden
Research Group
QCD/DiCarlo Lab (QuTech Advanced Research Centre) (TU Delft)
Copyright: © 2018 X. Bonet Monroig, R.E. Sagastizabal, M Singh, T.E. O'Brien
DOI
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https://doi.org/10.1103/PhysRevA.98.062339
More Info
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Published Date

2018

Language

English

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Faculty

QuTech Advanced Research Centre

Department

Quantum Computing Division

Research Group

QCD/DiCarlo Lab

Abstract

We investigate the performance of error mitigation via measurement of conserved symmetries on near-term devices. We present two protocols to measure conserved symmetries during the bulk of an experiment, and develop a third, zero-cost, post-processing protocol which is equivalent to a variant of the quantum subspace expansion. We develop methods for inserting global and local symmetries into quantum algorithms, and for adjusting natural symmetries of the problem to boost the mitigation of errors produced by different noise channels. We demonstrate these techniques on two- and four-qubit simulations of the hydrogen molecule (using a classical density-matrix simulator), finding up to an order of magnitude reduction of the error in obtaining the ground-state dissociation curve.