UT physics professor explores the interactions between light and matter

Radhika Vaishnav

UT physics associate professor Xiaoqin Elaine Li is studying the interaction between light and matter in quantum materials, which could lead to advances in everyday technology as soon as the next decade.

The area Li studies is referred to as the condensed matter of physics, or the study of the interaction between atoms in forms of matter where the atoms are very tightly packed together. When atoms are in this condensed state, they come together and begin to interact with each other.

“So that is interesting when you only have a few atoms, but when there are billions and billions of atoms shoved very close together, they all start connecting with each other through the principles called quantum mechanics,” physics department chair Jack Ritchie said.

Atoms are normally connected to each other by sharing electrons. When atoms become very closely acquainted, however, they begin to lose their identity in that they are no longer attached to any other single atom. This results in an electric current, which is essentially many electrons that have wandered off from their “host” atom, Ritchie said.

Li controls and studies how atoms and photons emitted from a laser beam interact with quantum materials, which are solid-like matters with tightly packed atoms. Lasers are crucial to her research because they have the ability to emit light of the same color, such as red or blue. Li probes one of these lasers that have just one photon of a specific color with a particular amount of energy toward special quantum materials that she can control. Then, she studies how these atoms interact with each other and the materials they are in contact with.

Li was recently awarded the 2018 Edith and Peter O’Donnell Award in Science from The Academy of Medicine, Engineering and Science of Texas. Additionally, Li has received a grant from Materials Research Science and Engineering Centers to continue her research.

“(With Li’s research), it becomes possible to imagine new types of applications,” Ritchie said. “For example, we rely very heavily on silicon chips for computers and cell phones, but the type of research she does allows us to explore new types of devices that would allow us to do things faster or maybe have higher densities so they can do more things in less space, and lead to a new type of technology.”