Yes, the most massive particle shows a “spooky action at a distance”
- The top quark, discovered in 1995, is the most massive elementary particle ever, surpassing even the Higgs boson.
- Because of its atypical size compared to other quarks, scientists were curious whether it exhibits quantum entanglement like other particles.
- Now, both ATLAS and CMS experiments at CERN’s Large Hadron Collider have detected entanglement between top quarks. This discovery could help to unravel further mysteries of this incredible “spooky action at a distance.”
Essentially, every atom consists of two elementary particles: electrons and quarks. But not all quarks are the same. In fact, the standard model of physics – which was developed over the course of half a century – distinguishes six different types, including up, down, strange, charming, bottom and top quarks. Scientists only discovered the top quark about 30 years ago and it was the last piece of the quark puzzle. Because unlike the other quarks, the top quark is large compared to its subatomic brothers.
Top quarks have an impressive energy of 175.6 gigaelectronvolts (GeV) – about the same mass as the nucleus of gold – but only exist for 15 to 24 seconds before decaying into free particles. Due to the (relatively) massive mass of the top quark, it took decades after the discovery of the bottom quark for the US Fermilabs to develop an accelerator. able to detect the elusive particle.
In the 30 years since then, the study of the top quark has opened up new worlds of particle physics, and the discovery of the Higgs boson in 2012 revealed the close connection between the two particles. Now scientists at CERN have turned to studying the quantum properties of the top quark and discovered that, despite their mass, top quarks exhibit quantum entanglement like other elementary particles.
In fall 2023, the Toroidal LHC Apparatus (ATLAS) experiment discovered entanglement between two top quarks, and earlier this week another CERN detector – the Compact Muon Solenoid (CMS) – also discovered quantum entanglement between top quarks. according to CERN. Specifically, the team discovered entanglement between the unstable top quark and its antimatter partner over distances “greater than what can be bridged by information travelling at the speed of light,” a press release states. In the famous words of Albert Einstein, what is known as “Spooky effect at a distance.”
To illustrate this strange effect of quantum mechanics, Regina Demina of the University of Rochester describes the idea in vivid terms in a Facebook video: She was part of the original team that discovered the top quark in 1995, was co-leader of a team that built the tracking device to search for the Higgs boson, and now leads the CMS team at the Large Hadron Collider at CERN:
“In a faraway land there lived a king. His name was Top, and he received news that his country was being attacked by his enemy. So he sent messengers to tell his constituents to defend themselves, but then he has a nightmare and changes his decision. And again he sent messengers to communicate his decision. He is constantly wavering and no one knows what his decision will be in the next moment. But there is one village that actually knows its decision exactly every time. The king of this village is Anti-Top. These are the particles we are dealing with: they know each other’s state of mind at any given moment.”
This type of entanglement is a hot topic in quantum information and quantum computing research, but top quarks can only be created in colliders. Even if they are not used in such next-generation machines, the discovery of their entanglement could answer questions about the nature of this “spooky action at a distance” – questions such as whether this entanglement persists after a particle decays and what ultimately resolves this entanglement.
It has been a long journey of discovery with regard to the top quark and there are probably many more secrets to be uncovered.
Darren lives in Portland, has a cat, and writes/edits about science fiction and how our world works. You can find his previous work at Gizmodo and Paste if you look hard enough.
The surprising connection of the Star-Spangled Banner to the English city
Veterans campaign to restore World War II tank memorial in Monessen City Park
North Korea criticizes Kishida’s visit to Germany as “collusion” with war criminals
About The Author
