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Detecting multipartite entanglement

Andrew C. Doherty·Pablo A. Parrilo·Federico M. Spedalieri
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Abstract

We discuss the problem of determining whether the state of several quantum mechanical subsystems is entangled. As in previous work on two subsystems we introduce a procedure for checking separability that is based on finding state extensions with appropriate properties and may be implemented as a semidefinite program. The main result of this work is to show that there is a series of tests of this kind such that if a multiparty state is entangled this will eventually be detected by one of the tests. The procedure also provides a means of constructing entanglement witnesses that could in principle be measured in order to demonstrate that the state is entangled.

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Andrew C. Doherty, Pablo A. Parrilo, Federico M. Spedalieri. 2004-07-19. Detecting multipartite entanglement. https://doi.org/10.1103/physreva.71.032333

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