1,169 research outputs found
Entanglement conditions for two-mode states
We provide a class of inequalities whose violation shows the presence of
entanglement in two-mode systems. We initially consider observables that are
quadratic in the mode creation and annihilation operators and find conditions
under which a two-mode state is entangled. Further examination allows us to
formulate additional conditions for detecting entanglement. We conclude by
showing how the methods used here can be extended to find entanglement in
systems of more than two modes.Comment: 4 pages, replaced with published versio
Entanglement criteria and nonlocality for multi-mode continuous variable systems
We demonstrate how to efficiently derive a broad class of inequalities for
entanglement detection in multi-mode continuous variable systems. The
separability conditions are established from partial transposition (PT) in
combination with several distinct necessary conditions for a quantum physical
state, which include previously established inequalities as special cases.
Remarkably, our method enables us to support Peres' conjecture to its full
generality within the framework of Cavalcanti-Foster-Reid-Drummond multipartite
Bell inequality [Phys. Rev. Lett. 99}, 210405 (2007)] that the nonlocality
necessarily implies negative PT entangled states.Comment: 4 pages, publishe
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