Accessible information and optimal strategies for real symmetrical quantum sources
Abstract
We study the problem of optimizing the Shannon mutual information for sources of real quantum states i.e. sources for which there is a basis in which all the states have only real components. We consider in detail the sources of equiprobable qubit states lying symmetrically around the great circle of real states on the Bloch sphere and give a variety of explicit optimal strategies. We also consider general real group-covariant sources for which the group acts irreducibly on the subset of all real states and prove the existence of a real group-covariant optimal strategy, extending a theorem of Davies (E. B. Davies, IEEE. Inf. Theory {\bf IT-24}, 596 (1978)). Finally we propose an optical scheme to implement our optimal strategies, enough simple to be realized with present technology.
Cite
@article{arxiv.quant-ph/9812062,
title = {Accessible information and optimal strategies for real symmetrical quantum sources},
author = {Masahide Sasaki and Stephen M. Barnett and Richard Jozsa and Masao Osaki and Osamu Hirota},
journal= {arXiv preprint arXiv:quant-ph/9812062},
year = {2009}
}
Comments
RevTeX, 16 pages, 4 eps figures with psfig, submitted to Phys. Rev. A, corrected output error of Fig. 1 in the previous version