Abstract

We introduce a new kind of quantum measurement that is defined to be symmetric in the sense of uniform Fisher information across a set of parameters that uniquely represent pure quantum states in the neighborhood of a fiducial pure state. The measurement is locally informationally complete—i.e., it uniquely determines these parameters, as opposed to distinguishing two arbitrary quantum states—and it is maximal in the sense of a multiparameter quantum Cramér-Rao bound. For a -dimensional quantum system, requiring only local informational completeness allows us to reduce the number of outcomes of the measurement from a minimum close to but below , for the usual notion of global pure-state informational completeness, to .

Date

2016

Authors

Nan Li, Christopher Ferrie, Jonathan A Gross, Amir Kalev, Carlton M Caves

Journal

Physical review letters

Volume

116

Issue

18

Pages

180402

Publisher

American Physical Society