Reversing quantum dynamics with near-optimal quantum and classical fidelity
Quantum Physics
2026-01-21 v2
Abstract
We consider the problem of reversing quantum dynamics, with the goal of preserving an initial state's quantum entanglement or classical correlation with a reference system. We exhibit an approximate reversal operation, adapted to the initial density operator and the ``noise'' dynamics to be reversed. We show that its error in preserving either quantum or classical information is no more than twice that of the optimal reversal operation. Applications to quantum algorithms and information transmission are discussed.
Cite
@article{arxiv.quant-ph/0004088,
title = {Reversing quantum dynamics with near-optimal quantum and classical fidelity},
author = {H. Barnum and E. Knill},
journal= {arXiv preprint arXiv:quant-ph/0004088},
year = {2026}
}
Comments
Revised to correct an error in the proof of the main theorem that prevented the extension to ensembles of more than one density matrix. Edited for clarity