Quantum Effects Discovered in Top Quark Pairs Challenge Classical Physics

A new study by the CMS collaboration has revealed quantum effects in top quark-antiquark pairs. The findings challenge classical predictions and offer a fresh perspective on particle interactions. The results have been published in Physical Review D. The team observed discord, a basic quantum correlation, at over 5σ significance in several phase space regions. This marks the first experimental confirmation of a hierarchy in quantum correlations for top quarks, with discord as the foundation.

They also detected steerability, a more complex form of entanglement, with a significance exceeding 3σ in a high-energy system. Additionally, magic—another quantum correlation measure—was observed at 5σ significance in multiple regions.

No Bell correlation was found within the examined phase space, which aligns with existing theoretical models. Together, discord, steerability, and magic signals point to intricate quantum connections shaping top quark behaviour. The findings provide direct evidence of quantum effects where classical physics predicts none. They also introduce a new framework for interpreting collider data. The study strengthens the understanding of quantum correlations in high-energy particle systems.