Department of Physics, Harvard University, Cambridge, Massachusetts 02138, USA.
ITAMP, Harvard-Smithsonian Center for Astrophysics, Cambridge, Massachusetts 02138, USA.
Phys Rev Lett. 2019 Feb 1;122(4):040603. doi: 10.1103/PhysRevLett.122.040603.
We analyze quantum dynamics of strongly interacting, kinetically constrained many-body systems. Motivated by recent experiments demonstrating surprising long-lived, periodic revivals after quantum quenches in Rydberg atom arrays, we introduce a manifold of locally entangled spin states, representable by low-bond dimension matrix product states, and derive equations of motion for them using the time-dependent variational principle. We find that they feature isolated, unstable periodic orbits, which capture the recurrences and represent nonergodic dynamical trajectories. Our results provide a theoretical framework for understanding quantum dynamics in a class of constrained spin models, which allow us to examine the recently suggested explanation of "quantum many-body scarring" [Nat. Phys. 14, 745 (2018)NPAHAX1745-247310.1038/s41567-018-0137-5], and establish a possible connection to the corresponding phenomenon in chaotic single-particle systems.
我们分析了强相互作用、动力学约束多体系统的量子动力学。受最近实验的启发，这些实验表明在里德堡原子阵列中量子淬火后会出现令人惊讶的长时间周期性复兴，我们引入了一组局部纠缠自旋态，它们可以用低键维矩阵乘积态表示，并使用含时变分原理推导出它们的运动方程。我们发现它们具有孤立的、不稳定的周期轨道，这些轨道捕获了重现并代表非遍历动力学轨迹。我们的结果为理解一类约束自旋模型中的量子动力学提供了一个理论框架，使我们能够检验最近提出的“量子多体伤痕”的解释[Nat. Phys. 14, 745 (2018)NPAHAX1745-247310.1038/s41567-018-0137-5]，并建立了与混沌单粒子系统中相应现象的可能联系。
