Optimal tracking for pairs of qubit states
Abstract
In classical control theory, tracking refers to the ability to perform measurements and feedback on a classical system in order to enforce some desired dynamics. In this paper we investigate a simple version of quantum tracking, namely, we look at how to optimally transform the state of a single qubit into a given target state, when the system can be prepared in two different ways, and the target state depends on the choice of preparation. We propose a tracking strategy that is proved to be optimal for any input and target states. Applications in the context of state discrimination, state purification, state stabilization and state-dependent quantum cloning are presented, where existing optimality results are recovered and extended.
Cite
@article{arxiv.0802.3896,
title = {Optimal tracking for pairs of qubit states},
author = {Paulo E. M. F. Mendonca and Alexei Gilchrist and Andrew C. Doherty},
journal= {arXiv preprint arXiv:0802.3896},
year = {2008}
}
Comments
15 pages, 8 figures. Extensive revision of text, optimality results extended, other physical applications included