Maximum Observable Correlation for a Bipartite Quantum System

Date

2006

Authors

Hall, Michael
Andersson, Erika
Brougham, Thomas

Journal Title

Journal ISSN

Volume Title

Publisher

American Physical Society

Abstract

The maximum observable correlation between the two components of a bipartite quantum system is a property of the joint density operator, and is achieved by making particular measurements on the respective components. For pure states it corresponds to making measurements diagonal in a corresponding Schmidt basis. More generally, it is shown that the maximum correlation may be characterized in terms of a correlation basis for the joint density operator, which defines the corresponding (nondegenerate) optimal measurements. The maximum coincidence rate for spin measurements on two-qubit systems is determined to be (1+s)2, where s is the spectral norm of the spin correlation matrix, and upper bounds are obtained for n -valued measurements on general bipartite systems. It is shown that the maximum coincidence rate is never greater than the computable cross norm measure of entanglement, and a much tighter upper bound is conjectured. Connections with optimal state discrimination and entanglement bounds are briefly discussed.

Description

Keywords

Keywords: Computation theory; Correlation methods; Measurement theory; Optimization; Bipartite quantum systems; Joint density operators; Schmidt basis; Spin measurements; Quantum electronics

Citation

Source

Physical Review A: Atomic, Molecular and Optical Physics

Type

Journal article

Book Title

Entity type

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2037-12-31