For the first time, researchers from Universität Hamburg's Institute of Laser Physics have created a time crystal that spontaneously breaches continuous time translation symmetry.

They describe their findings in a study published online by Science on Thursday, June 9, 2022.

Nobel Laureate Franck Wilczek was the one who initially presented the concept of a time crystal.

The time translation symmetry in a dynamical many-body system suddenly breaks when a time crystal forms, similar to how water spontaneously turns into ice near the freezing point, breaking the system's translation symmetry.

Researchers have discovered discrete or Floquet time crystals in regularly driven closed and open quantum systems in recent years.

However, in all prior experiments, a time-periodic drive has broken the continuous-time translation symmetry,' explains Dr. Hans Keßler of Prof. Andreas Hemmerich's group at the Cluster of Excellence CUI: Advanced Imaging of Matter.

'The goal for us was to create a system that breaks the continuous time translation symmetry on its own.'

The researchers used a Bose-Einstein condensate inside an optical high-finesse cavity in their experiment.

They found a limit cycle phase defined by emergent periodic oscillations of the intracavity photon number accompanied by atomic density cycling through recurrent patterns using a time-independent pump.

They discovered that the oscillations' temporal phase takes random values between 0 and 2, as one would expect from spontaneously broken continuous symmetry.

The researchers established the durability of the dynamic phase by locating the stability area in the relevant parameter space and demonstrating the persistence of the limit cycle oscillations even in the presence of strong temporal perturbations.