标题： 无极化预热离散时间晶体 显示英文标题

标题： Unpolarized prethermal discrete time crystal

摘要： 预热离散时间晶体（DTCs）是一类非平衡物质相，表现出对周期驱动的鲁棒次谐波响应，且不需要无序环境。 先前预热DTCs的实现依赖于自发或诱导有限极化现象的存在。 在这里，我们引入了一类新的预热DTCs，称为未极化预热离散时间晶体（UPDTCs），它不需要有限极化。 通过研究一个周期性驱动囚禁离子的自旋模型，我们表明，在抗磁初始状态下，稳健的倍周期动力学可以在交错磁化自相关函数中持续存在，即使交错磁化本身消失。 关键见解是量子涨落本身足以揭示相干DTC样动力学。 我们证明，在高频驱动下，UPDTCs的寿命呈指数级增长，这与Floquet预热一致。 我们的结果扩展了已知的预热时间晶体的特性，并强调了量子效应在稳定新型非平衡相中的作用。 我们提出了一个实验方案，以在囚禁离子模拟器中观察UPDTCs。 显示英文摘要

摘要： Prethermal discrete time crystals (DTCs) are a class of nonequilibrium phases of matter that exhibit robust subharmonic responses to periodic driving without requiring disorder. Prior realizations of prethermal DTCs have relied on the presence of either spontaneous or induced finite polarization. Here, we introduce a new class of prethermal DTCs termed unpolarized prethermal discrete time crystals (UPDTCs) that do not require finite polarization. By studying a spin model of periodically driven trapped ions, we show that robust period-doubled dynamics can persist in the autocorrelation function of the staggered magnetization for paramagnetic initial states, even when the staggered magnetization itself vanishes. The key insight is that quantum fluctuations alone are sufficient to reveal coherent DTC-like dynamics. We demonstrate that UPDTCs are exponentially long-lived in the high-frequency driving regime, consistent with Floquet prethermalization. Our results expand the known phenomenology of prethermal time crystals and underscore the role of quantum effects in stabilizing novel nonequilibrium phases. We propose an experimental protocol to observe UPDTCs in trapped-ion simulators.