When you pop a tray of water into the freezer, you get ice cubes. Now, researchers from CU Boulder and the University of Toronto have achieved a similar transition using clouds of ultracold atoms.
In a study published today in the journal Science Advances, the team discovered that it could nudge these quantum materials to undergo transitions between “dynamical phases”—essentially, jumping between two states in which the atoms behave in completely different ways.
“This happens abruptly, and it resembles the phase transitions we see in systems like water becoming ice,” said study coauthor Ana Maria Rey. “But unlike that tray of ice cubes in the freezer, these phases don’t exist in equilibrium. Instead, atoms are constantly shifting and evolving over time.”
The findings, she added, provide a new window into materials that are hard to investigate in the laboratory.
“If you want to, for example, design a quantum communications system to send signals from one place to another, everything will be out of equilibrium,” said Rey, a fellow at JILA, a joint institute between CU Boulder and the National Institute of Standards and Technology (NIST). “Such dynamics will be the key problem to understand if we want to apply what we know to quantum technologies.”
Credit: “Turning water into ice in the quantum realm”, Daniel Strain, University of Colorado Boulder