Zhao Hanqing, Smalyukh Ivan I
Department of Physics, University of Colorado, Boulder, CO, USA.
International Institute for Sustainability with Knotted Chiral Meta Matter (WPI-SKCM²), Hiroshima University, Hiroshima, Japan.
Nat Mater. 2025 Sep 4. doi: 10.1038/s41563-025-02344-1.
Time crystals are unexpected states of matter that spontaneously break time-translation symmetry either in a discrete or continuous manner. However, spatially mesoscale space-time crystals that break both space and time symmetries have not been reported. Here we report a continuous space-time crystal in a nematic liquid crystal driven by ambient-power, constant-intensity unstructured light. Our numerically constructed four-dimensional configurations exhibit good agreement with these experimental findings. Although meeting the established criteria to identify time-crystalline order, both experiments and computer simulations reveal a space-time crystallization phase formed by particle-like topological solitons. The robustness against temporal perturbations and spatiotemporal dislocations shows the stability and rigidity of the studied space-time crystals, which relates to their locally topological nature and many-body interactions between emergent spontaneously twisted, particle-like solitonic building blocks. Their potential technological utility includes optical devices, photonic space-time crystal generators, telecommunications and anti-counterfeiting designs, among others.
时间晶体是一种意想不到的物质状态，它以离散或连续的方式自发地打破时间平移对称性。然而，尚未有关于同时打破空间和时间对称性的空间中尺度时空晶体的报道。在此，我们报告了一种由环境功率、恒定强度的非结构化光驱动的向列型液晶中的连续时空晶体。我们通过数值构建的四维构型与这些实验结果显示出良好的一致性。尽管符合确定时间晶体序的既定标准，但实验和计算机模拟均揭示了由类粒子拓扑孤子形成的时空结晶相。对时间扰动和时空位错的鲁棒性表明了所研究的时空晶体的稳定性和刚性，这与其局部拓扑性质以及涌现的自发扭曲的类粒子孤子构建块之间的多体相互作用有关。它们潜在的技术用途包括光学器件、光子时空晶体发生器、电信和防伪设计等。
