Scientists create strange quantum "domain walls" in the lab

Scientists at the University of Chicago have been able to create a new kind of quantum object at will in the lab. Domain Wall. The discovery could help researchers better understand exotic quantum particles — and could give a path to future new technologies, such as quantum electronics or quantum memory.

The study, published in the journal Nature on February 2, 2022, was conducted in Professor Cheng Chin's lab, which studies novel quantum systems and the physics that underpin them. In one of their experiments, scientists at the University of Chicago noticed an interesting phenomenon in atoms at extremely low temperatures. Under the right conditions, groups of atoms can be separated into domains and form a "wall" at the junction where they meet. This domain wall behaves like a separate quantum object.

Yao Kaixuan, lead author of the study and phD student, said: "It's a bit like a dune in the desert, it's made of sand, but the dune behaves like an object, unlike a single grain of sand. "

Scientists have glimpsed these domain walls in quantum materials, but before, they could not reliably generate and analyze them. Now, physicists at the University of Chicago have created recipes that make and carefully study these walls, and they have observed surprising behavior. Scientists are interested in orchestrating these behaviors, in part because they could be the basis for future technologies.

"We have a lot of experience in controlling atoms," said Chin, who was appointed to the Department of Physics, the James Frank Institute and the Enrico-Fermi Institute. "We know that if you push the atoms to the right, they move to the right. But here, if you push the domain wall to the right, it will move to the left. These domain walls are part of a class of phenomena known as 'emergences,' meaning they seem to follow new laws of physics, the result of the collective action of many particles as a whole.

Chin's lab studies these emergences, arguing that they could elucidate a set of laws known as dynamic gauge theory, which describes materials and other emergent phenomena in the early universe, and macroscopically, the same phenomena that could have clumped together when the first particles came together to form galaxies, stars, and planets.

Breakthroughs in this area could also enable new quantum technologies. Scientists are interested in cataloguing these behaviors, in part because they could be the basis for future technologies — for example, the foundations of modern GPS stem from scientists in the 1950s trying to test Einstein's theory of relativity.

"There could be applications for this phenomenon in making programmable quantum materials or quantum information processors — it could be used to create a more powerful way to store quantum information, or to implement new functions in materials," Chin said. "But before we can discover that, the first step is to understand how to control them."