Quantum correlations and least disturbing local measurements

Journal Article · Tue Nov 15 04:00:00 EST 2011 · Physical Review. A

DOI:https://doi.org/10.1103/PHYSREVA.84.052329· OSTI ID:22093498

Rossignoli, R.; Canosa, N.; Ciliberti, L. ^[1]

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1. Departamento de Fisica-IFLP, Universidad Nacional de La Plata, C.C. 67, La Plata (1900) (Argentina)

We examine the evaluation of the minimum information loss due to an unread local measurement in mixed states of bipartite systems, for a general entropic form. Such a quantity provides a measure of quantum correlations, reducing for pure states to the generalized entanglement entropy, while in the case of mixed states it vanishes just for classically correlated states with respect to the measured system, as the quantum discord. General stationary conditions are provided, together with their explicit form for general two-qubit states. Closed expressions for the minimum information loss as measured by quadratic and cubic entropies are also derived for general states of two-qubit systems. As an application, we analyze the case of states with maximally mixed marginals, where a general evaluation is provided, as well as X states and the mixture of two aligned states.

• OSTI ID: 22093498
• Journal Information: Physical Review. A, Journal Name: Physical Review. A Journal Issue: 5 Vol. 84; ISSN 1050-2947; ISSN PLRAAN
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
CORRELATIONS
ENTROPY
EVALUATION
LOSSES
MIXED STATE
MIXTURES
QUANTUM ENTANGLEMENT
QUANTUM MECHANICS
QUANTUM STATES
QUBITS