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Q: Fachverband Quantenoptik und Photonik
Q 32: Quantum Information: Concepts and Methods V
Q 32.5: Talk
Wednesday, March 8, 2017, 15:30–15:45, P 2
Quantum fidelity of symmetric multipartite states — •Antoine Neven1, Pierre Mathonet2, Otfried Gühne3, and Thierry Bastin1 — 1CESAM Research Unit, Institut de Physique Nucléaire, Atomique et de Spectroscopie, Université de Liège, 4000 Liège, Belgium — 2Département de Mathématique, Université de Liège, 4000 Liège, Belgium — 3Naturwissenschaftlich-Technische Fakultät, Universität Siegen, D-57068 Siegen, Germany
For two symmetric quantum states one may be interested in maximizing the overlap under local operations applied to one of them. The question arises whether the maximal overlap can be obtained by applying the same local operation to each party. We show [1] that for two symmetric multiqubit states and local unitary transformations this is the case; the maximal overlap can be reached by applying the same unitary matrix everywhere. For local invertible operations (stochastic local operations assisted by classical communication equivalence), however, we present counterexamples, demonstrating that considering the same operation everywhere is not enough.
[1] A. Neven, P. Mathonet, O. Gühne, and T. Bastin, Phys. Rev. A 94, 052332 (2016).