Using adaptiveness and causal superpositions against noise in quantum metrology
Abstract
We derive new bounds on achievable precision in the most general adaptive quantum metrological scenarios. The bounds are proven to be asymptotically saturable and equivalent to the known parallel scheme bounds in the limit of large number of channel uses. This completely solves a long standing conjecture in the field of quantum metrology on asymptotic equivalence between parallel and adaptive strategies. The new bounds also allow to easily assess the potential benefits of invoking the non-standard causal superposition strategies, for which we prove, similarly to the adaptive case, the lack of asymptotic advantage over the parallel ones.
Keywords
Cite
@article{arxiv.2212.08106,
title = {Using adaptiveness and causal superpositions against noise in quantum metrology},
author = {Stanislaw Kurdzialek and Wojciech Gorecki and Francesco Albarelli and Rafal Demkowicz-Dobrzanski},
journal= {arXiv preprint arXiv:2212.08106},
year = {2023}
}
Comments
We added proof that the causal superposition channel from appendix C is well defined. We showed how to obtain a tighter bound for a parallel case (appendix D3)