Realization of a time-crystal in a dc-driven atom-cavity system

直流驱动原子腔系统中时间晶体的实现

• 批准号: 426796523
• 负责人: Dr. Hans Keßler
• 金额: --
• 依托单位: Institut für Laser-Physik
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2019
• 资助国家: 德国
• 起止时间: 2018-12-31 至 2022-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/426796523?language=en
• 关键词: Realization; time; crystal; dc; driven

The central objective of this proposal is to experimentally realize a dc driven time-crystal using an atom-cavity system comprising a Bose-Einstein condensate (BEC) strongly coupled to a high-finesse low-bandwidth optical cavity. To this end, I propose to employ the so far experimentally unexplored regime of pump light, which is blue detuned with respect to the relevant atomic resonances. Theoretical preparatory work indicates excellent chances that this endeavour should succeed. The mean-field and truncated Wigner simulations presented in the project description predict a rich phase diagram with four distinct many-body states: a homogenous BEC phase, a density wave phase, a time-crystal phase and a chaotic phase. Above a critical pump strength, the atomic sample forms a self-organized Bragg grating referred to as density wave phase. This phase becomes unstable above a second threshold value of the pump strength. The resulting non-equilibrium state of matter breaks the time-translation symmetry and realizes the concept of a time-crystal. All so far realized time-crystals break a discrete time-translation symmetry and are therefore called Floquet time-crystals. A notable novelty of this project is the creation of a time-crystal that breaks a continuous time-translation symmetry, such that a more stringent analogy to the concept of spatial crystals holds.

这个建议的中心目标是实验实现一个直流驱动的时间晶体使用原子腔系统，包括玻色-爱因斯坦凝聚体（BEC）强耦合到一个高精细度低带宽的光学腔。为此，我建议采用迄今为止实验上未探索的泵浦光制度，这是蓝色失谐相对于相关的原子共振。理论上的准备工作表明，这一努力取得成功的机会很大。项目描述中提出的平均场和截断维格纳模拟预测了一个丰富的相图，其中包含四种不同的多体状态：均匀BEC相，密度波相，时间晶体相和混沌相。在临界泵浦强度以上，原子样品形成称为密度波相位的自组织布拉格光栅。该相位在泵浦强度的第二阈值以上变得不稳定。由此产生的物质非平衡态打破了时间平移对称性，实现了时间晶体的概念。迄今为止，所有实现的时间晶体都打破了离散的时间平移对称性，因此被称为Floquet时间晶体。这个项目的一个值得注意的新奇是创造了一种打破连续时间平移对称的时间晶体，这样就可以更严格地类比空间晶体的概念。