Rostock 2019 – scientific programme

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Q: Fachverband Quantenoptik und Photonik

Q 41: Poster: Quantum Optics and Photonics II

Q 41.10: Poster

Wednesday, March 13, 2019, 16:15–18:15, S Fobau Physik

Bound entanglement in d x d symmetric mixed states — •Marcel Seelbach Benkner — University of Siegen, Germany

Entanglement is the key resource that enables many quantum information processing tasks, and its detection and quantification has been considered at length in the past decades. However, even in the bipartite case, open questions still remain to be answered. So-called bound entangled states are especially enigmatic, and remain elusive to be fully characterized both theoretically and experimentally. Bound entanglement appears in highly mixed states, for which entanglement quantification methods are generically hard to implement. We introduce a family of bipartite mixed quantum states in arbitrary dimensions, where invariance under cyclic permutations of the local basis elements and phase rotations is the defining property. We apply several entanglement detection criteria, and show that a sizable part of the family is bound entangled. Furthermore we solve the separability problem for a subset of these states. To get quantitative results on the entanglement of the family, we consider the case of two ququarts and compute a lower bound for the linear entropy using semidefinite programming. Because our family is defined through symmetries, these results stand also as lower bounds for the linear entropy of generic nonsymmetric states of the same dimension.