Einstein’s “Spooky Action” Survives One of Physics’ Most Extreme Tests

Oxford physicists and the ATLAS collaboration at the Large Hadron Collider have for the first time shown entanglement between pairs of Z bosons produced in Higgs boson decays. The result, published in Physical Review Letters, is one of the highest-energy confirmations of quantum entanglement.

• Entanglement recorded between Z boson pairs from Higgs boson decay
• Protons collided at 13 TeV at 99.99% the speed of light
• Z boson spins reconstructed from electron and muon emission angles
• Entanglement was previously observed in top quarks in the 2023 ATLAS experiment