Quantum Breakthrough: Top Quarks Reveal Hidden Hierarchy at Record Energies
For the first time, scientists have confirmed a hierarchy of quantum correlations in top quark-antiquark systems. The findings, made using the Large Hadron Collider (LHC), reveal strong evidence of these effects at record-breaking energy levels. This breakthrough connects high-energy physics with quantum information science in a new way.
The CMS collaboration at the LHC carried out the experiment, focusing on top quark-antiquark pairs produced at 13 TeV. Unlike earlier studies on lower-energy particles, this work examined top quarks—each with a mass of 172 GeV—using over 100,000 high-purity events. By analysing angular correlations in decay products, researchers measured entanglement through the OTOC witness observable.
The top quark's spin information is preserved in its decay, allowing precise quantification of quantum correlations. The team identified four types in a clear hierarchy: discord, entanglement, steering, and Bell correlation. Notably, the observed discord exceeded 5σ, providing robust proof of quantum effects in this extreme energy regime.
Advanced techniques, including machine learning and boosted topologies, helped distinguish entanglement from classical correlations. These methods also enabled sensitivity to quantum chromodynamics (QCD) effects at distances as small as 10⁻¹⁹ metres. The results mark the first time such correlations have been probed at this scale in a collider environment.
This work opens new possibilities for studying quantum mechanics using high-energy particle data. The LHC's ability to explore quantum phenomena at unprecedented energy levels could lead to further discoveries. Scientists now have a powerful tool to investigate fundamental aspects of quantum information in extreme conditions.
