Researchers at the University of Colorado Boulder have achieved a significant breakthrough in condensed matter physics by successfully creating visible time crystals using liquid crystals. This innovative approach, detailed in the journal Nature Materials on September 4, 2025, allows for the direct observation of these unique structures under standard laboratory conditions. This marks a departure from previous methods that relied on complex quantum systems.
The study, titled "Space-time crystals from particle-like topological solitons," was led by graduate student Hanqing Zhao and Professor Ivan Smalyukh. Time crystals represent a novel phase of matter characterized by periodic motion in time without continuous energy input, challenging conventional thermodynamic principles. Unlike spatial crystals with repeating patterns in space, time crystals exhibit a dynamic, time-based order. The foundational concept of time crystals was first proposed by Nobel laureate Frank Wilczek in 2012.
The CU Boulder team's method involves utilizing rod-shaped liquid crystal molecules confined within glass cells. When exposed to specific light sources, these molecules induce persistent motion patterns that can be observed as time-evolving structures. These patterns remain stable for extended periods, demonstrating the robustness of the time crystal phase. The formation of "kinks," localized distortions in the molecular arrangement, plays a crucial role. Under light exposure, dye molecules coating the glass exert forces that create these kinks, causing them to move and interact in complex, choreographed sequences.
This advancement holds considerable promise for practical applications. The ability to observe time crystals directly under an ordinary microscope simplifies experimental setups and paves the way for integration into tangible technologies. Potential applications include ultra-secure authentication measures, such as "time watermarks" on currency, and advanced data storage solutions by stacking multiple layers of these time crystals to create intricate patterns.
Previous efforts to create time crystals involved quantum systems, notably in 2021 when a team utilized Google's Sycamore quantum processor. However, the CU Boulder group's innovation stands out by harnessing classical liquid crystals, making direct observation feasible and significantly simplifying experimental procedures. This marks a crucial step in translating the theoretical promise of time crystals from abstract quantum phenomena to practical, observable realities.
The experimental setup involves sandwiching liquid crystals between glass plates coated with light-responsive dye molecules. When illuminated, these dyes exert mechanical forces on the liquid crystals, triggering the emergence of kinks. These topological solitons, acting as discrete, quasi-particle entities, interact to produce collective temporal ordering grounded in classical physics, bridging the gap between quantum time crystals and macroscopic observable effects. This breakthrough enriches fundamental physics by providing a tangible manifestation of time-translation symmetry breaking in a classical system, challenging long-held assumptions and inspiring new theoretical and experimental investigations.