Scientists discover first evidence of matter-matter coupling

A new study reveals the first-ever evidence of matter-matter coupling.

Tyler MacDonald | Oct 19, 2019

A new study from Rice University scientists revealed the first evidence of Dicke cooperativity in a matter-matter system. The findings could help evolve our understanding of quantum magnetism and spintronics.

The team used a magnetic field to induce cooperativity among spins within a crystalline compound created primarily from erbium and iron.

"This is an emerging subject in condensed matter physics," Kono said. "There's a long history in atomic and molecular physics of looking for the phenomenon of ultrastrong cooperative coupling. In our case, we'd already found a way to make light and condensed matter interact and hybridize, but what we're reporting here is more exotic."

Dicke cooperativity occurs when incoming radiation causes a group of atomic dipoles to couple, much like gears within a motor that don't touch.

"Dicke was an unusually productive physicist," Kono said. "He had many high-impact papers and accomplishments in almost all areas of physics. The particular Dicke phenomenon that's relevant to our work is related to superradiance, which he introduced in 1954. The idea is that if you have a collection of atoms, or spins, they can work together in light-matter interaction to make spontaneous emission coherent. This was a very strange idea."

"The interaction we're talking about is really atomistic," Kono concluded. "We show two types of spin interacting in a single material. That's a quantum mechanical interaction, rather than the classical mechanics we see in light-matter coupling. This opens new possibilities for not only understanding but also controlling and predicting novel phases of condensed matter."

The findings were published in Science.