Hannover 2016 – scientific programme

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Q: Fachverband Quantenoptik und Photonik

Q 37: Quantum Information: Concepts and Methods VI

Q 37.8: Talk

Wednesday, March 2, 2016, 16:15–16:30, e214

Proving multipartite entanglement from separable marginals — •Marius Paraschiv, Nikolai Miklin, Tobias Moroder, and Otfried Gühne — Universität Siegen Department Physik Emmy-Noether-Campus Walter-Flex-Straße 3 57068 Siegen Germany

We address here the question of whether or not global entanglement of a quantum state can be inferred from local properties. Specifically, we are interested in genuinely entangled multipartite states whose two-body marginals are separable. Due to the fact that any biseparable state is also a PPT mixture, we can focus only on the class of fully decomposable entanglement witnesses. This type of witness is positive for all PPT mixtures. The problem thus formulated naturally falls within the field of semidefinite programming (SDP). By running an iteration over two different SDPs, one for the global quantum state with PPT two-body marginals, the other for the witness, fully decomposable and restricted to two-body interactions, we have found states that obey the above requirements for up to 6 qubits. We present an analytical construction of such states for an arbitrary number of particles.