Evrim Yazgin
Cosmos science journalist
Smashing protons together at CERN’s Large Hadron Collider has led to the first observation of quantum entanglement of quarks.
Einstein once called quantum entanglement “spooky action at a distance.”
It is an effect in quantum mechanics where 2 or more particles become linked. The “entangled” particles share a single physical state and share information instantaneously. Theoretically, this entangled state persists no matter how far apart the particles are separated.
This effect is being investigated for potential technological advances including “unhackable” encryption in quantum computers.
Entanglement has been observed in electrons, streams of photons, molecules and even across many atoms.
The new study, published in Nature, reports the highest energy observation of entanglement.
It uses data from the Large Hadron Collider (LHC) ATLAS collaboration. The results were later confirmed by another experiment using the CMS (Compact Muon Solenoid) detector at the LHC.
“While particle physics is deeply rooted in quantum mechanics, the observation of quantum entanglement in a new particle system and at much higher energy than previously possible is remarkable,” says ATLAS spokesperson Andreas Hoecker. “It paves the way for new investigations into this fascinating phenomenon, opening up a rich menu of exploration as our data samples continue to grow.”
The LHC collaborations observed quantum entanglement between a top quark and its antimatter counterpart.
Quarks are fundamental particles which make up the protons and neutrons in atomic nuclei. There are 17 fundamental particles in the Standard Model of particle physics. Six of them are different kinds of quarks: up, down, strange, charm, bottom and top.
The top quark is the heaviest known fundamental particle. Its mass is about 184 times that of a proton – about the same as a rhenium atom.
ATLAS and CMS physicists observed quark entanglement through proton-proton collisions at an energy of 13 teraelectronvolts (roughly 2 millionths of a joule). The experiments ran between 2015 and 2018.
They noticed the quarks’ spin entangled by measuring the direction of the particles produced by the decay of the quarks.
“With measurements of entanglement and other quantum concepts in a new particle system and at an energy range beyond what was previously accessible, we can test the Standard Model of particle physics in new ways and look for signs of new physics that may lie beyond it.” says CMS spokesperson Patricia McBride.
