https://doi.org/10.1140/epja/s10050-024-01314-6
Regular Article - Theoretical Physics
Restoring symmetries in quantum computing using Classical Shadows
Université Paris-Saclay, CNRS/IN2P3, IJCLab, 91405, Orsay, France
b
denis.lacroix@ijclab.in2p3.fr
Received:
30
January
2024
Accepted:
8
April
2024
Published online:
24
May
2024
We introduce a method to enforce some symmetries starting from a trial wave-function prepared on quantum computers that might not respect these symmetries. The technique eliminates the necessity for performing the projection on the quantum computer itself. Instead, this task is conducted as a post-processing step on the system’s “Classical Shadow”. Illustrations of the approach are given for the parity, particle number, and spin projectors that are of particular interest in interacting many-body systems. We compare the method with another classical post-processing technique based on direct measurements of the quantum register. We show that the present scheme can be competitive to predict observables on symmetry-restored states once optimization through derandomization is employed. The technique is illustrated through its application to compute the projected energy for the pairing model Hamiltonian.
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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.
