Schematic drawing of the spin maser experimental setup. Credit: NTSC

Time crystals represent a new phase of matter proposed by Frank Wilczek, the Nobel laureate of Âé¶¹ÒùÔºics in 2004; they can break original time-translation symmetry and create new time oscillations spontaneously.

Recently, a joint research team from the National Time Service Center (NTSC) of the Chinese Academy of Sciences and Shanghai Jiao Tong University observed a time crystal in a maser system.

The results are in Communications Âé¶¹ÒùÔºics.

In this study, the researchers investigated a Rb-Xe hybrid atomic spin maser system. They discovered that when the interaction strength of the spin-feedback magnetic field surpasses that of the spin–DC , a distinct spin oscillation signal emerges. The signal oscillates with a totally different from that of the original spin Larmor precession, and it has random phases and shows high robustness over repeated experiments, fitting the definition of .

Dependency of the time crystal on the amplitude and phase of the feedback magnetic field. Credit: NTSC

"Our research provides an alternative scheme to the existing time crystals," said Prof. Liu Guobin, leader of the atomic spin gyroscope research group from NTSC.

The time crystal in a spin maser could potentially be used for both fundamental studies and practical applications based on precision measurement physics.

More information: Weiyu Wang et al, Observation of time crystal in a spin maser system, Communications Âé¶¹ÒùÔºics (2025).

Journal information: Communications Âé¶¹ÒùÔºics