Quantifying entanglement with witness operators

Journal Article · Mon Aug 15 04:00:00 EDT 2005 · Physical Review. A

DOI:https://doi.org/10.1103/PhysRevA.72.022310· OSTI ID:20718069

We present a unifying approach to the quantification of entanglement based on entanglement witnesses, which includes several already established entanglement measures such as the negativity, the concurrence, and the robustness of entanglement. We then introduce an infinite family of new entanglement quantifiers, having as its limits the best separable approximation measure and the generalized robustness. Gaussian states, states with symmetry, states constrained to super-selection rules, and states composed of indistinguishable particles are studied under the view of the witnessed entanglement. We derive new bounds to the fidelity of teleportation d{sub min}, for the distillable entanglement E{sub D} and for the entanglement of formation. A particular measure, the PPT-generalized robustness, stands out due to its easy calculability and provides sharper bounds to d{sub min} and E{sub D} than the negativity in most of the states. We illustrate our approach studying thermodynamical properties of entanglement in the Heisenberg XXX and dimerized models.

• OSTI ID: 20718069
• Journal Information: Physical Review. A, Journal Name: Physical Review. A Journal Issue: 2 Vol. 72; ISSN 1050-2947; ISSN PLRAAN
• Country of Publication: United States
• Language: English

Related Subjects

74 ATOMIC AND MOLECULAR PHYSICS
HEISENBERG MODEL
INFORMATION THEORY
QUANTUM ENTANGLEMENT
QUANTUM TELEPORTATION
SELECTION RULES
SYMMETRY
THERMODYNAMIC PROPERTIES