Title: Quantum Entanglement and Bell Inequality Violation at Colliders

Speaker: Kun Cheng, Peking University

Time: 02:00 pm, Apr.25th，2024

Venue: C302, New Science Building

Abstract: The research of entanglement phenomena in particle physics has been gathering pace. When massive particle pairs with spin are produced at colliders their spins are correlated. When the particle pair system is interpreted as a quantum state, the system can exhibit entanglement and can violate Bell's inequality. However, compared to measuring spin correlation, studying the quantum properties of spin states requires first defining a "quantum state", and this process has some artificial arbitrariness. The commonly used event-by-event axis choice leads to an artificial contructed state, which is basis dependent. In addition, experimentally the spin of the tt/WW cannot be measured , and one need to determine the spin density matrix of tt/WW pair from their decay final states that are detectable. Then choosing a proper Bell observable can reduce the experimental difficulty.

Bio: Kun Cheng is a fifth year PhD studuent at Peking University with a broad interest in high energy physics.He has worked on collider physics, NP beyond the SM and global symmetry of scalar potential.During his visit in University of Pittsburgh in 2023, he also became interested in spin correlation and quantum entanglement at colliders.