Random qubit-states and how best to measure them

Barnett, S.M. (2010) Random qubit-states and how best to measure them. Journal of Modern Optics, 57 (3). pp. 232-238. ISSN 0950-0340

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    Abstract

    We consider the problem of measuring a single qubit, known to have been prepared in either a randomly selected pure state or a randomly selected real pure state. We seek the measurements that provide either the best estimate of the state prepared or maximise the accessible information. Surprisingly, any sensible measurement turns out to be optimal. We discuss the application of these ideas to multiple qubits and higher-dimensional systems.