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Title: Noise resilience of variational quantum compiling
Abstract

Variational hybrid quantum-classical algorithms (VHQCAs) are near-term algorithms that leverage classical optimization to minimize a cost function, which is efficiently evaluated on a quantum computer. Recently VHQCAs have been proposed for quantum compiling, where a target unitaryUis compiled into a short-depth gate sequenceV. In this work, we report on a surprising form of noise resilience for these algorithms. Namely, we find one often learns the correct gate sequenceV(i.e. the correct variational parameters) despite various sources of incoherent noise acting during the cost-evaluation circuit. Our main results are rigorous theorems stating that the optimal variational parameters are unaffected by a broad class of noise models, such as measurement noise, gate noise, and Pauli channel noise. Furthermore, our numerical implementations on IBM’s noisy simulator demonstrate resilience when compiling the quantum Fourier transform, Toffoli gate, and W-state preparation. Hence, variational quantum compiling, due to its robustness, could be practically useful for noisy intermediate-scale quantum devices. Finally, we speculate that this noise resilience may be a general phenomenon that applies to other VHQCAs such as the variational quantum eigensolver.

Authors:
; ; ;
Publication Date:
NSF-PAR ID:
10303243
Journal Name:
New Journal of Physics
Volume:
22
Issue:
4
Page Range or eLocation-ID:
Article No. 043006
ISSN:
1367-2630
Publisher:
IOP Publishing
Sponsoring Org:
National Science Foundation
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