From nonlocality transitivity to entanglement transitivity and more

19 January 2026

Title: From nonlocality transitivity to entanglement transitivity and more

Speaker: Professor, Deputy Director Yeong-Cherng Liang, Department of Physics | QFort, National Cheng Kung University, Taiwan

Abstract of Talk : In this seminar, I shall first recall the phenomenon of Bell-nonlocality and the related transitivity problem --- a problem that concerns the possibility of inferring the Bell-nonlocality of certain marginals in a multipartite scenario based on partial information. Then, I explain how considering this problem has led to the analogous entanglement transitivity problem. Surprisingly, one can always find examples of entanglement transitivity by considering the marginal density matrices of Haar-random tripartite pure states. In a similar spirit, we have also shown that large marginals are generically entangled across all cuts. Finally, I demonstrate how examples of entanglement transitivity have led to the first quantum-realizable notion of nonlocality transitivity.

Profile of Speaker: Yeong-Cherng Liang is a quantum theorist specializing in the studies of entanglement, Bell-nonlocality, and other quantum features, as well as their applications in quantum information processing tasks. He is currently a Physics Professor and the Deputy Director of the Center for Quantum Frontiers of Research & Technology based at the National Cheng Kung University, Taiwan. He obtained his Ph.D. from the University of Queensland in 2008 and held postdoctoral positions at the University of Sydney, the University of Geneva, and ETH Zürich. Among others, he is a co-recipient of the Paul Ehrenfest Best Paper Award for Quantum Foundations for the Year 2023