A team from the University of Chicago has announced the first evidence for “quantum superchemistry”—a phenomenon where particles in the same quantum state undergo collective accelerated reactions. The effect had been predicted, but never observed in the laboratory.
Chin’s group is experienced with herding atoms into quantum states, but molecules are larger and much more complex than atoms—so the group had to invent new techniques to wrangle them.
In the experiments, the scientists cooled down cesium atoms and coaxed them into the same quantum state. Next, they watched as the atoms reacted to form molecules.
In ordinary chemistry, the individual atoms would collide, and there’s a probability for each collision to form a molecule. However, quantum mechanics predicts that atoms in a quantum state perform actions collectively instead.
One consequence is that the reaction happens faster than it would under ordinary conditions. In fact, the more atoms in the system, the faster the reaction happens.
Another consequence is that the final molecules share the same molecular state. Chin explained that the same molecules in different states can have different physical and chemical properties—but there are times when you want to create a batch of molecules in a specific state. In traditional chemistry, you’re rolling the dice. “But with this technique, you can steer the molecules into an identical state,” he said.
More information: Zhendong Zhang et al, Many-body chemical reactions in a quantum degenerate gas, Nature Physics (2023). DOI: 10.1038/s41567-023-02139-8