Inside the 20-year quest to unravel the bizarre realm of 'quantum superchemistry'

By Sam Lemonick, March 29, 2024, LiveScience.com

More than two decades ago, scientists predicted that at ultra-low temperatures, many atoms could undergo 'quantum superchemistry' and chemically react as one. They've finally shown it's real.

Chemistry depends on heat.

Atoms or molecules bounce around randomly, collide, and form other molecules. At higher temperatures, atoms collide more and the rate at which atoms become molecules increases. Below a certain temperature, the reaction won't happen at all.

But something very weird happens at the lowest temperatures. In this extreme cold, there is essentially no heat energy, yet chemical reactions happen faster than they do at high temperatures.

Quantum superchemistry is a strange phenomenon in which particles undergo collective chemical reactions. It was finally demonstrated in 2023, when ultra-cold cesium atoms were converted to cesium molecules, and then back again. (Image credit: koto_feja via Getty Images)

And it was finally demonstrated last year, more than 20 years after physicists first proposed it.

In that experiment, University of Chicago physicist Cheng Chin and colleagues coaxed a group of cesium atoms at just a few nanokelvin into the same quantum state. Amazingly, each atom did not interact separately. Instead, 100,000 atoms reacted as one, almost instantaneously.

The first demonstration of this weird process has opened a window for scientists to better understand how chemical reactions operate in the strange realm of quantum mechanics, which governs the behavior of subatomic particles. It also may help to simulate quantum phenomena that classic computers struggle to model accurately, such as superconductivity.

But what happens after that, as with so many advances in research, is hard to predict. Chin, for one, has no plans to stop studying this strange form of chemistry

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