Physicists confirm quantum entanglement in some of the heaviest, most fleeting particles ever created

[Pete14]

Physicists at the University of Oxford, working with the ATLAS experiment at CERN's Large Hadron Collider, have helped confirm that quantum entanglement occurs even among some of the heaviest and shortest lived particles ever produced in a laboratory. The result, published in Physical Review Letters, comes from studying Z boson pairs produced when a Higgs boson briefly splits into two Z bosons before each decays further into pairs of electrons or muons. By reconstructing the angles at which those final decay particles were emitted, researchers could infer the spins of the original Z bosons and test whether they were genuinely linked by entanglement.

Einstein famously called entanglement spooky action at a distance, and it has previously been demonstrated across a range of systems including photons, electrons, and trapped ions, all comparatively stable and long lived by particle physics standards. Extending that same demonstration to Z bosons produced in collisions at trillions of times higher energy than typical laboratory quantum experiments, and existing for only an almost unimaginably brief fraction of a second before decaying, represents a genuinely different regime for testing whether quantum mechanics holds up as cleanly as it does at more familiar, gentler energy scales.

Beyond its purely fundamental significance, Oxford researchers frame this as part of a growing effort to borrow tools and concepts from quantum information science and apply them directly to particle physics data analysis. That cross pollination is helping physicists develop more sensitive analytical techniques for collider data generally, with the potential to reveal subtle effects that might eventually point toward genuinely new physics beyond the current Standard Model.

Professor Barr, who co-leads a major interdisciplinary project at Oxford exploring the foundations of quantum mechanics at high energies, framed the broader motivation as testing quantum mechanics under the most extreme conditions physically achievable, at energies and length scales where the theory might conceivably start to break down in ways that would have profound consequences for the foundations of physics itself

Physicists Uncover Spooky Quantum Effectphys.org