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THU: Thursday Contributed Sessions

THU 13: Poster Session: Applications

THU 13.20: Poster

Thursday, September 11, 2025, 16:30–18:30, ZHG Foyer 1. OG

Activation of Genuine Multipartite Entanglement and Genuine Multipartite Nonlocality — •Markus Miethlinger, Bora Ulu, Alejandro Pozas-Kerstjens, Sadra Boreiri, Pavel Sekatski, and Nicolas Brunner — Department of Applied Physics, University of Geneva, 1211 Geneva 4, Switzerland

Entanglement and nonlocality have long been central to the study of quantum foundations. It is known that bipartite nonlocality can be activated–i.e., preparing multiple copies of a local state can result in a nonlocal one–in stark contrast to bipartite entanglement, which cannot be activated. However, recent results show that genuine multipartite entanglement (GME) can be activated from fully inseparable biseparable states, and that genuine multipartite nonlocality (GMNL) can be activated using bilocal states. Furthermore, GME is recognized as a necessary condition for GMNL in the single-copy regime. Yet, the simultaneous activation of GME and GMNL–i.e., activating GMNL using biseparable states–has not been studied. Here, we show that GMNL can be activated using multiple copies of a fully local, N−1 separable state in a star network. We consider a family of states and identify a threshold number of copies for which the global state remains biseparable, as well as a sufficient condition for it to be GME above this threshold. Using a multipartite nonlocal game featuring unbounded Bell inequality violations, we derive a sufficient condition for the states to be GMNL-activatable. This result shows that single-copy GME is not a necessary condition for GMNL activation, and may indicate that GME and GMNL coincide in the asymptotic limit.

Keywords: Genuine Multipartite Entanglement; GME Activation; Genuine Multipartite Nonlocality; GMNL Activation