At the collider, they studied pairs of top quarks — their spins can be quantum-linked. The connection comes in different flavors: from weak 'discordant' to strong 'steerable' (which was spotted for the first time). But the most peculiar one, the 'Bell' correlation, wasn't found. It’s like two friends who always dress alike without ever planning it. Why is nature playing hide-and-seek like this?
At the Large Hadron Collider, by accelerating particles to nearly light speeds, top quarks are created — the heaviest building blocks of the Standard Model. They live for vanishingly small fractions of a second but manage to exhibit complex quantum connections.
These connections are like levels of dance synchronization. Discord is when two people move in a common rhythm but each on their own (here, entropy, a measure of disorder, is useful). With entanglement, which Erwin Schrödinger considered the essence of the quantum world, one partner instantly responds to the other's movements. Steerability is the ability of a leader to dictate the steps to a follower. And perfect harmony, like in a rehearsed ballet, is Bell correlation, named after John Stewart Bell.
CMS detected discord and steerability in top quarks but did not find Bell correlations. The surprise was 'quantum magic' — a state where quantum properties are so non-classical that they cannot be reproduced on ordinary computers.
🎯 The top quark is nearly 200 times more massive than the proton and vanishes faster than a trillionth of a second. In that brief moment, it exhibits the most complex quantum connections.
🎬 In 'The Quantum Thief,' quantum correlations are used for faster-than-light communication; the real experiment shows that connections are even more diverse — from discord to quantum magic — opening up room for imagination.