Conditions for compatibility of quantum state assignments
Abstract
Suppose N parties describe the state of a quantum system by N possibly different density operators. These N state assignments represent the beliefs of the parties about the system. We examine conditions for determining whether the N state assignments are compatible. We distinguish two kinds of procedures for assessing compatibility, the first based on the compatibility of the prior beliefs on which the N state assignments are based and the second based on the compatibility of predictive measurement probabilities they define. The first procedure leads to a compatibility criterion proposed by Brun, Finkelstein, and Mermin [BFM, Phys. Rev. A 65, 032315 (2002)]. The second procedure leads to a hierarchy of measurement-based compatibility criteria which is fundamentally different from the corresponding classical situation. Quantum mechanically none of the measurement-based compatibility criteria is equivalent to the BFM criterion.
Cite
@article{arxiv.quant-ph/0206110,
title = {Conditions for compatibility of quantum state assignments},
author = {Carlton M. Caves and Christopher A. Fuchs and Ruediger Schack},
journal= {arXiv preprint arXiv:quant-ph/0206110},
year = {2009}
}
Comments
REVTEX 4, 19 pages, 1 postscript figure