Can local hidden-variable theories be excluded at colliders?

Tue, 07 Apr 2026 08:28:10 +0000

Terça-feira, 14 de Abril 2026 das 16:00 às 18:00

DF Seminar Room (2-8.3), 2nd floor of Physics Building

Recently, there has been an increased interest in possible tests of locality via Bell's inequality or tests of entanglement at colliders, in particular at the LHC. These have involved various physical processes, such as top-anti-top, or tau+tau- production, or the decay of a Higgs boson to two vector bosons H->VV*.

In this talk, we argue that none of these proposals constitutes a test of locality via Bell's inequality or a test of quantum entanglement without assuming an underlying quantum field theory, such as the Standard Model. In all cases, what is measured is the momenta of the final state particles.

Using the construction proposed by Kasday (1971) in a different context, and adapted to collider scenarios by Abel, Dittmar, and Dreiner (1992), it is straightforward to construct a local hidden variable theory (LHVT) which exactly reproduces the data. This construction is only possible as the final state momenta all commute. …

Unfolding the Time Structure of Quantum Chromodynamics in Heavy-Ion Collisions

Thu, 09 Apr 2026 13:28:13 +0000

Quarta-feira, 29 de Abril 2026 das 16:00 às 18:00

Anfiteatro PA2 (Piso -1 do Pavilhão de Matemática) do IST

Ultra-relativistic heavy-ion collisions recreate, for fleeting instants, the hottest and densest conditions known in the Universe — a phase where quarks and gluons exist in a strongly-coupled state known as the Quark–Gluon Plasma (QGP). These environments, produced at facilities like the Large Hadron Collider (CERN) and the Relativistic Heavy Ion Collider (Brookhaven National Laboratory), allow us to reveal fundamental aspects of Quantum Chromodynamics (QCD), the theory of the strong interaction. Jets, collimated sprays of particles initiated by high-energy quarks or gluons, are among the most powerful probes, capable of traversing the evolving QGP and interacting with its constituents.

Traditionally studied in energy-momentum space and regarded as mathematical tools rather than physical entities, jets were long considered to be virtual constructs. Yet recent theoretical and phenomenological efforts have revealed that, in the presence of a medium, jets acquire real space-time features, a new physical layer that leave measurable imprints on experimental …

Eventos

Can local hidden-variable theories be excluded at colliders?

Unfolding the Time Structure of Quantum Chromodynamics in Heavy-Ion Collisions