Disentanglement in bipartite continuous-variable systems

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

DOI:https://doi.org/10.1103/PHYSREVA.84.052330· OSTI ID:22093499

Barbosa, F. A. S.; Coelho, A. S.; Nussenzveig, P.; Martinelli, M. ^[1]; Faria, A. J. de ^[2]; Cassemiro, K. N. ^[1]; Villar, A. S. ^[1]

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1. Instituto de Fisica, Universidade de Sao Paulo, P.O. Box 66318, 05315-970 Sao Paulo (Brazil)
2. Instituto de Cie circumflex ncia e Tecnologia, Universidade Federal de Alfenas, 37715-400 Pocos de Caldas, MG (Brazil)

Entanglement in bipartite continuous-variable systems is investigated in the presence of partial losses such as those introduced by a realistic quantum communication channel, e.g., by propagation in an optical fiber. We find that entanglement can vanish completely for partial losses, in a situation reminiscent of so-called entanglement sudden death. Even states with extreme squeezing may become separable after propagation in lossy channels. Having in mind the potential applications of such entangled light beams to optical communications, we investigate the conditions under which entanglement can survive for all partial losses. Different loss scenarios are examined, and we derive criteria to test the robustness of entangled states. These criteria are necessary and sufficient for Gaussian states. Our study provides a framework to investigate the robustness of continuous-variable entanglement in more complex multipartite systems.

• OSTI ID: 22093499
• 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
74 ATOMIC AND MOLECULAR PHYSICS
DATA TRANSMISSION
LOSSES
OPTICAL FIBERS
POTENTIALS
QUANTUM ENTANGLEMENT
QUANTUM MECHANICS
QUANTUM STATES
VISIBLE RADIATION