Q-CORR_Quantenkorrelationen - von zwei zu vielen Teilchen
Zusammenfassung der Projektergebnisse
Detecting and experimentally verifying genuine multipartite entanglement, i.e., entanglement truly involving several parties, which cannot be generated using local operations and classical communication from bipartite entangled states, is still a hard task. Yet, given the possible applications, it is surely worth it. Nonclassical correlations between measurement results are the characteristic property of entangle quantum states. Yet, although this is so remarkably strong for pairs of particles, it becomes quite fuzzy for an increasing number of parties. Correlations also provide a useful way to characterize a state and to describe joint measurements of several observers, the standard definition of correlations does not comply with some basic postulates. In this project this has been demonstrated with the provocative experimental result of studying quantum states both in theory and in experiment, which violates multi-party Bell inequalities, but do not show any multi-partite correlations. We have proposed a class of multipartite (highdimensional) states without standard correlations, which provide some testbed for studying operationally meaningful redefinitions of multipartite quantum correlations. The requirement to find the optimal alignment between the observers of multi-party quantum states is of course carefully addressed in all the experiments. However, what happens, if we cannot warrant enough stability in the experiment? Or, seen from a different viewpoint, how much can I say about a quantum state from random measurements of multiple observers? This can be answered to the positive. Entanglement can be identified, and even multi-party states can be distinguished solely based on studying the correlations between the observers. To prove entanglement it is indeed not necessary to perfectly align all the observers with respect to each other. The statistics of the correlations is clearly different as the perfect correlations still survive when analyzing the frequency of the correlation values for the different states.
Projektbezogene Publikationen (Auswahl)
-
Higher dimensional entanglement without correlations. The European Physical Journal D, 73(2).
Kłobus, Waldemar; Laskowski, Wiesław; Paterek, Tomasz; Wieśniak, Marcin & Weinfurter, Harald
-
Multipartite entanglement analysis from random correlations. npj Quantum Information, 6(1).
Knips, Lukas; Dziewior, Jan; Kłobus, Waldemar; Laskowski, Wiesław; Paterek, Tomasz; Shadbolt, Peter J.; Weinfurter, Harald & Meinecke, Jasmin D. A.
-
Cooperation and dependencies in multipartite systems. New Journal of Physics, 23(6), 063057.
Kłobus, Waldemar; Miller, Marek; Pandit, Mahasweta; Ganardi, Ray; Knips, Lukas; Dziewior, Jan; Meinecke, Jasmin; Weinfurter, Harald; Laskowski, Wiesław & Paterek, Tomasz
-
Gaussian state entanglement witnessing through lossy compression. Physical Review A, 103(3).
Kłobus, Waldemar; Cieśliński, Paweł; Knips, Lukas; Kurzyński, Paweł & Laskowski, Wiesław
