Detecting multipartite entanglement

  title={Detecting multipartite entanglement},
  author={Andrew C. Doherty and Pablo A. Parrilo and Federico M. Spedalieri},
  journal={Physical Review A},
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… 
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