Revealing Bell’s nonlocality for unstable systems in high energy physics

• Published in: The European physical journal. C, Particles and fields Particles and fields, 2012, Vol.72 (1), p.1-6, Article 1856
• Main Authors: Hiesmayr, Beatrix C., Di Domenico, Antonio, Curceanu, Catalina, Gabriel, Andreas, Huber, Marcus, Larsson, Jan-Åke, Moskal, Pawel
• Format: Article
• Language: English
• Subjects: Antimatter; Astronomy; Astrophysics and Cosmology; Bell's inequality; CP violation; Elementary Particles; Entanglement; Exact sciences and technology; Hadrons; Heavy Ions; Letter; MATEMATIK; MATHEMATICS; Measurement Science and Instrumentation; Nuclear Energy; Nuclear Physics; Physics; Physics and Astronomy; Quantum Field Theories; Quantum Field Theory; Realism; String Theory; The physics of elementary particles and fields
• ISSN: 1434-6044; 1434-6052; 1434-6052
• DOI: 10.1140/epjc/s10052-012-1856-x

Entanglement and its consequences—in particular the violation of Bell inequalities, which defies our concepts of realism and locality—have been proven to play key roles in Nature by many experiments for various quantum systems. Entanglement can also be found in systems not consisting of ordinary matter and light, i.e. in massive meson–antimeson systems. Bell inequalities have been discussed for these systems, but up to date no direct experimental test to conclusively exclude local realism was found. This mainly stems from the fact that one only has access to a restricted class of observables and that these systems are also decaying. In this Letter we put forward a Bell inequality for unstable systems which can be tested at accelerator facilities with current technology. Herewith, the long awaited proof that such systems at different energy scales can reveal the sophisticated “ dynamical ” nonlocal feature of Nature in a direct experiment gets feasible. Moreover, the role of entanglement and violation, an asymmetry between matter and antimatter, is explored, a special feature offered only by these meson–antimeson systems.