Scientists at the University of Oklahoma and JILA at the University of Colorado Boulder have published collaborative research findings in the journal Nature that provide new insights into the behavior of superconducting materials and offer potential novel applications in the field of quantum technologies.
"Our paper reports a breakthrough in the development of quantum simulators, a type of specialized quantum computer that mimics complex physical systems that would be impossible to study or understand otherwise," said Robert Lewis-Swan, co-author and an assistant professor of atomic, molecular and optical physics in OU's Center for Quantum Research and Technology. "This work was heavily inspired by research I published in 2021 showing that this type of simulator, based on an atom-cavity system, could be adapted to observe phenomena that would be very difficult to investigate in other settings."
The researchers explored the emergence of out-of-equilibrium phases in a Bardeen-Cooper-Schrieffer, or BCS, superconductor. The BCS superconductivity theory was developed in 1957 by John Bardeen, Leon Cooper and John Robert Schrieffer, and describes how electrons moving in opposite directions can bind together into pairs that can condense into a superfluid state that can conduct electricity with zero resistance at low temperatures.
"The simulator uses atoms cooled to almost one-millionth of a degree above absolute zero trapped inside a cavity with highly reflective mirrors that bounce light back and forth for a very long time. The atoms effectively interact with each other by emitting and absorbing photons of light inside the cavity," Lewis-Swan said. "Through this atom-light system, we were able to observe all three dynamical phases in BCS superconductors for the first time."
The breakthrough findings of this study provide new insights into the behavior of superconducting materials and offer potential applications in the field of quantum technology. They also demonstrate that programmable simulators using quantum atoms and light can be used to study models that don't naturally occur in nature.
"It's intellectually stimulating to be able to work with these experimental groups that operate at such a high level," Lewis-Swan said. "As a theorist, I can write equations down on a piece of paper and I run simple numerical calculations on my computer. But it's really exciting to see my theory come alive inside the real experimental system."
Learn more about the Center for Quantum Research and Technology in the Dodge Family College of Arts and Sciences at the University of Oklahoma.
