MIT Physicists Spin Ultra-Cold Atoms To Form Quantum Tornadoes

Physicists at the Massachusetts Institute of Technology (MIT) have coaxed a bunch of ultra-chilled atoms to exhibit a never before seen phenomenon: a crystal made of “quantum tornadoes.” In the 1980s, a lot of particle physics activity that eventually led to the discovery of a new family of matter known as quantum Hall fluids and consisting of clouds of electrons suspended in magnetic fields.

Photo Insert: Quantum tornadoes

Classical physics dictates that the electrons in the Hall ‘fluid’ should repel each other and arrange themselves in an orderly lattice, forming a crystal. Except that no. Just no. Instead, the particles always adjusted their behavior to what their neighbors were doing, all in a correlated way, reported Tibi Puiu for ZME Science.

“People discovered all kinds of amazing properties, and the reason was, in a magnetic field, electrons are (classically) frozen in place—all their kinetic energy is switched off, and what’s left is purely interactions,” says Richard Fletcher, assistant professor of physics at MIT.

“So, this whole world emerged. But it was extremely hard to observe and understand.”

Fletcher and Martin Zwierlein, the Thomas A. Frank Professor of Physics at MIT, wondered if they could replicate this effect in an experiment that makes it easier to see. Electrons in a magnetic field move in very small increments, and the researchers thought that since the motion of atoms under rotation can occur over much larger length scales, they could afford to use ultracold atoms in lieu of electrons to make a nice light show.

For their study, they used lasers to trap around one million sodium atoms, cooling them to around 100 nanokelvins, a hair’s breadth away from absolute zero. A system of electromagnets both further confined the atoms and collectively spun them around like marbles in a bowl at about 100 rotations per second.

Using high-speed precision optical cameras to observe what was happening at the molecular level, the physicists found that the atoms spun into a long thread at around the 100-millisecond mark. According to the researchers, the evolution of the spinning atoms in the gas broadly mimics how Earth’s rotation creates large-scale weather patterns. A fine example of how the very small and the very large are not that disconnected as the wackiness of quantum physics might lend us to believe.

“The Coriolis effect that explains Earth’s rotational effect is similar to the Lorentz force that explains how charged particles behave in a magnetic field,” Zwierlein notes. “Even in classical physics, this gives rise to intriguing pattern formation, like clouds wrapping around the Earth in beautiful spiral motions. And now we can study this in the quantum world.” The study was published in the journal Nature.

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