In a remarkable feat, scientists at the Large Hadron Collider (LHC) have observed quantum entanglement between fundamental particles, opening up new frontiers in our understanding of the quantum world.
Revealing Quantum Mysteries
Quantum entanglement is one of those mind-bending phenomena, where the state of one particle cannot be described independently irrespective of the state of another, no matter how far apart they are. It has not classical counterpart in the world we know – No one observed it in any target.
The observation of quantum entanglement in high energy particle collisions has taken place, ironically enough for the first time ever, at LHC. Although entanglement has been studied in the past with low-energy experiments, the LHC, by virtue of being at the cutting edge of particle physics research, is a powerful tool for probing deep into this quantum conundrum.
End of a Line for top Quarks
This week the ATLAS and CMS collaborations at the LHC are reporting that they have observed quantum entanglement between top quarks, the heaviest known elementary particles. Top quarks are produced in pairs at LHC, and the researchers focused on selecting pairs that included two slow-moving protons. In particular this would be the region in which we expect the spins of those top quarks to be most entangled.
When they looked at the electrically charged decay products of the top quarks in detail, examining how often these particles split off from each other by particular angles, they could determine whether or not these particles were entangled in their spins. The entanglement was seen by both the ATLAS and CMS teams independently, with a statistical significance greater than five standard deviations; an observation that sets aside all doubts.
The CMS collaboration also investigated high-momentum top quark pairs in which both quarks were relatively fast-moving. It showed that the relative positions and times of the two top quark decays must be such that classical exchange of information is impossible, yet spin entanglement between the top quarks was still observed.
Conclusion
The observation of quantum entanglement in top quarks at the LHC is a great milestone in our comprehension of the quantum world. With the new results, physicists have truly reached a new era in probing the depths of nature at its most fundamental level — and one that comes with an exciting menu of possibilities for exploration. It is hoped that, as long as the LHC continues to take data, it will reveal even more surprises which can help push back the frontier of our understanding.
