https://doi.org/10.1140/epjp/s13360-024-05143-w
Regular Article
Control landscapes for high-fidelity generation of C-NOT and C-PHASE gates with coherent and environmental driving
1
Department of Mathematical Methods for Quantum Technologies, Steklov Mathematical Institute of Russian Academy of Sciences, 8 Gubkina str, 119991, Moscow, Russia
2
University of Science and Technology MISIS, 4 Leninskiy Prospekt, 119991, Moscow, Russia
a
apechen@gmail.com
https://www.mathnet.ru/eng/person17991
Received:
7
November
2023
Accepted:
30
March
2024
Published online:
14
May
2024
High-fidelity generation of two-qubit gates is important for quantum computation, since such gates are components of popular universal sets of gates. Here, we consider the problem of high-fidelity generation of two-qubit C-NOT and C-PHASE (with a detailed study of C–Z) gates in presence of the environment. We consider the general situation when qubits are manipulated by coherent and incoherent controls; the latter is used to induce generally time-dependent decoherence rates. For estimating efficiency of optimization methods for high-fidelity generation of these gates, we study quantum control landscapes which describe the behavior of the fidelity as a function of the controls. For this, we generate and analyze the statistical distributions of best objective values obtained by incoherent GRadient Ascent Pulse Engineering (inGRAPE) approach. We also apply inGRAPE and a dual annealing algorithm (DAA) based on a stochastic zeroth-order method to numerically estimate minimal infidelity values. The results are different from the case of single-qubit gates and indicate a smooth trap-free behavior of the fidelity.
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© The Author(s), under exclusive licence to Società Italiana di Fisica and Springer-Verlag GmbH Germany, part of Springer Nature 2024. Springer Nature or its licensor (e.g. a society or other partner) holds exclusive rights to this article under a publishing agreement with the author(s) or other rightsholder(s); author self-archiving of the accepted manuscript version of this article is solely governed by the terms of such publishing agreement and applicable law.
