Bonn 2025 – wissenschaftliches Programm
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QI: Fachverband Quanteninformation
QI 20: Quantum Networks (joint session QI/Q)
QI 20.1: Hauptvortrag
Mittwoch, 12. März 2025, 14:30–15:00, HS VIII
Generating entangled states in quantum networks — •Nikolai Wyderka1, Justus Neumann1, Tulja Varun Kondra1, Kiara Hansenne2, Lisa T. Weinbrenner2, Hermann Kampermann1, Otfried Gühne2, and Dagmar Bruß1 — 1Institut für Theoretische Physik III, Heinrich-Heine-Universität Düsseldorf, Universitätsstraße 1, 40225 Düsseldorf, Germany — 2Naturwissenschaftlich-Technische Fakultät, Universität Siegen, Walter-Flex-Straße 3, 57068 Siegen, Germany
Which states can be generated in quantum networks? We investigate this question in n-partite quantum networks connected by bipartite sources, assuming local operations and shared randomness (LOSR). We show that for many target states, the question can be reduced to the tripartite network scenario.
Consequently, we show that for the class of multipartite graph states, the reducibility is connected to the task of Greenberger-Horne-Zeilinger (GHZ) state extraction. Here, one asks whether n parties that share a graph state and are distributed into three groups can create a GHZ state shared between them using only group-local unitary operations. We show that for each connected graph state, it is always possible to find a tripartition that yields at least one GHZ state.
Finally, we exploit our findings to derive fidelity bounds on states preparable in LOSR networks with any graph state by deriving strong fidelity bounds in tripartite quantum networks.
Keywords: Quantum networks; graph states; entanglement