Activation of post-quantum steering

Journal article

There are possible physical theories that give greater violations of Bell’s inequalities than the corresponding Tsirelson bound, termed post-quantum non-locality. Such theories do not violate special relativity, but could give an advantage in certain information processing tasks. There is another way in which entangled quantum states exhibit non-classical phenomena, with one notable example being Einstein–Podolsky–Rosen (EPR) steering; a violation of a bipartite Bell inequality implies EPR steering, but the converse is not necessarily true. The study of post-quantum EPR steering is more intricate, but it has been shown that it does not always imply post-quantum non-locality in a conventional Bell test. In this work we show how to distribute resources in a larger network that individually do not demonstrate post-quantum non-locality but violate a Tsirelson bound for the network. That is, we show how to activate post-quantum steering so that it can now be witnessed as post-quantum correlations in a Bell scenario. One element of our work that may be of independent interest is we show how to self-test a bipartite quantum assemblage in a network, even assuming post-quantum resources.

Authors: Belén Sainz, A; Skrzypczyk, P; Hoban, MJ

• Publication status: Published
• Peer review status: Peer reviewed
• Publisher: IOP Publishing
• Journal: New Journal of Physics
• Volume: 27
• Issue: 12
• Article number: 124508
• Publication date: 2025-12-08
• Acceptance date: 2025-11-20
• DOI: 10.1088/1367-2630/ae21fe
• EISSN: 1367-2630
• ISSN: 1367-2630
• Language: English
• Keywords: Podolsky; post-quantum nonlocality; Einstein; self-testing; Rosen steering; Bell nonlocality