论文标题
在远距离XYZ旋转链中的连续时间晶体和多体疤痕之间调节
Tuning between continuous time crystals and many-body scars in long-range XYZ spin chains
论文作者
论文摘要
非平衡多体系统中的持续振荡动力学是刺激性崩溃的诱人表现,它继续引起很多关注。最近的工作集中在两类此类系统上:离散的时间晶体和量子多体疤痕(QMB)。尽管这两个系统主机振荡动力学,但其起源预计将在根本上不同:离散时间晶体是一个阶段,它会自发打破$ \ mathbb {z} _2 _2 _2 $对外部定期驱动器的对称性,而QMBS则跨越了非热功能特征的亚空间,形成了Sueigenstate(2)Algebra代表。在这里,我们提出一个基本问题:是否有一个物理系统可以在这两个动态现象之间进行调整?与以前的许多工作相反,我们研究了表现出细头化的非传播的,强调的系统中\ emph {连续}时间晶体(CTC)的可能性。我们引入了远程XYZ自旋模型,并表明它既包括CTC相位又包括QMB。我们使用数值模拟基于精确的对角线化和热力学极限中的时间依赖性变异原理来绘制动态相图。我们确定了QMB和CTC顺序共存的制度,并讨论了揭示其相似性以及关键差异的实验协议。
Persistent oscillatory dynamics in non-equilibrium many-body systems is a tantalizing manifestation of ergodicity breakdown that continues to attract much attention. Recent works have focused on two classes of such systems: discrete time crystals and quantum many-body scars (QMBS). While both systems host oscillatory dynamics, its origin is expected to be fundamentally different: discrete time crystal is a phase of matter which spontaneously breaks the $\mathbb{Z}_2$ symmetry of the external periodic drive, while QMBS span a subspace of non-thermalizing eigenstates forming an su(2) algebra representation. Here we ask a basic question: is there a physical system that allows to tune between these two dynamical phenomena? In contrast to much previous work, we investigate the possibility of a \emph{continuous} time crystal (CTC) in undriven, energy-conserving systems exhibiting prethermalization. We introduce a long-range XYZ spin model and show that it encompasses both a CTC phase as well as QMBS. We map out the dynamical phase diagram using numerical simulations based on exact diagonalization and time-dependent variational principle in the thermodynamic limit. We identify a regime where QMBS and CTC order co-exist, and we discuss experimental protocols that reveal their similarities as well as key differences.