Quantum observables over time for information recovery
File(s)
Published version
Author(s)
Bressanini, Gabriele
Kim, Myungshik
Kwon, Hyukjoon
Hanif, Farhan
Type
Journal Article
Abstract
We introduce the concept of quantum observables over time (QOOT), an operator that jointly describes two observables at two distinct time points, as a dual of the quantum state over time formalism. We provide a full characterization of the conditions under which a QOOT can be properly defined, via a no-go theorem. We use QOOTs to establish a notion of time-reversal for generic quantum channels with respect to a reference observable, enabling the systematic construction of recovery maps that preserve the latter. These recovery maps, although generally non-physical, can be decomposed into realizable channels, enabling their application in noiseless expectation value estimation tasks. We provide explicit examples and compare our protocol with other error mitigation methods. We show that our protocol retrieves the noiseless expectation value of the reference observable and can achieve optimal sampling overhead, outperforming probabilistic error cancellation.
Date Issued
2026-08-01
Date Acceptance
2026-05-18
Citation
Physical Review Research, 2026, 8 (3)
ISSN
2643-1564
Publisher
American Physical Society (APS)
Journal / Book Title
Physical Review Research
Volume
8
Issue
3
Copyright Statement
Copyright © 2026 The Author(s). Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOI.
License URL
Identifier
10.1103/schg-nl3m
Publication Status
Published
Article Number
033208
Date Publish Online
2026-08-19