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arXiv · 0802.3896

Optimal tracking for pairs of qubit states

Paulo E. M. F. Mendonca·Alexei Gilchrist·Andrew C. Doherty
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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.

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Paulo E. M. F. Mendonca, Alexei Gilchrist, Andrew C. Doherty. 2008-06-03. Optimal tracking for pairs of qubit states. https://doi.org/10.1103/physreva.78.012319

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