Instruments and mutual entropies in quantum information
Abstract
General quantum measurements are represented by instruments. In this paper the mathematical formalization is given of the idea that an instrument is a channel which accepts a quantum state as input and produces a probability and an a posteriori state as output. Then, by using mutual entropies on von Neumann algebras and the identification of instruments and channels, many old and new informational inequalities are obtained in a unified manner. Such inequalities involve various quantities which characterize the performances of the instrument under study; in particular, these inequalities include and generalize the famous Holevo's bound.
Cite
@article{arxiv.quant-ph/0412116,
title = {Instruments and mutual entropies in quantum information},
author = {Alberto Barchielli and Giancarlo Lupieri},
journal= {arXiv preprint arXiv:quant-ph/0412116},
year = {2007}
}
Comments
LaTeX, requires macros in mypreprint.sty, 16 pages. Submitted to Proceedings of the 25th Conference on "Quantum Probability and Related topics"