A shimmering crystal gets its colorful appearance from the precise arrangement of its atoms in space. In 2012, Nobel Prize-winning physicist Frank Wilczek proposed that a similar kind of order could exist not in space, but in time. He suggested that certain quantum systems could organize themselves into repeating patterns that continue indefinitely without needing energy from the outside. He called these systems time crystals. They exist in their lowest energy state while still exhibiting constant, repeating motion. Scientists confirmed their existence experimentally in 2016.

Researchers at Aalto University's Department of Applied Physics have now achieved a major milestone by linking a time crystal to an external system for the first time. The study, led by Academy Research Fellow Jere Mäkinen, shows how the team converted a time crystal into an optomechanical system.…