Particle physicists Detect Hints of quantum Entanglement in Top Quark Decay at Large Hadron Collider
Geneva, Switzerland – Physicists at the Large Hadron Collider (LHC) are reporting initial observations suggesting a connection between particle physics and quantum facts theory, perhaps offering a new way to test the foundations of quantum mechanics. Experiments focusing on the decay of top quarks – the heaviest known elementary particle – are yielding data that could illuminate the nature of entanglement and the transition from the quantum to the classical world, researchers announced in July.
The work, stemming from the ATLAS collaboration, builds on years of high-energy collisions at the LHC. According to Dr. Maarten Vos, a physicist involved in the research, the team has already produced a “tangible spin-off” in the form of new data analysis techniques applicable to both particle physics and quantum information science.
The core of the investigation centers on probing entanglement – a phenomenon where two or more particles become linked and share the same fate,no matter how far apart they are. Researchers are asking basic questions about what happens to entangled systems when particles decay. “What happens to your entangled system after the top quark decays? Will the daughters of the top quark still be entangled with the anti-top quark?” Vos asked, noting that while quantum field theory predicts continued entanglement, it has never been experimentally verified.
Beyond confirming theoretical predictions, the experiments offer a unique perspective on the quantum-to-classical transition. when a top quark decays into lighter particles, it appears to “choose” a spin direction, influencing the direction those particles travel. “Mathematically, it’s an equivalent process to making a measurement,” explained Dr. Shelly Barr, suggesting this decay process provides a novel angle for studying how quantum uncertainty resolves into definite classical states.
Some physicists are even hoping to use the LHC to investigate the nature of time itself. Dr. Olga Demina aims to experimentally demonstrate the Page-Wootters mechanism, a 1983 theory proposed by Don Page and William Wootters suggesting time may not be a fundamental property, but rather an emergent one arising from entanglement between spatial configurations. The mechanism was previously demonstrated with photons in 2013, and Demina hopes to replicate it using elementary particles.
However, the approach isn’t without its critics. Dr. Herbert Dreiner from the university of Bonn argues in two recent preprints (available here and here) that the methodology is circular.He contends that relating the angular motion of decay products to the quarks’ spins requires using quantum mechanics itself, making it impossible to truly test quantum mechanics.
This debate highlights a broader sentiment within the field. “There is a sense that you’re always looking for new things to do,” said Martin White, acknowledging the need for evolving research goals after 17 years of LHC experiments. Despite the skepticism, Vos remains optimistic. “You start pulling on the thread, and you don’t know what you’re going to come up with.”
The LHC continues to operate, and further analysis of the data is expected to provide more definitive answers to these fundamental questions about the universe and the bizarre world of quantum mechanics.
