Lim Lih-King, Lou Cunzhong, Tian Chushun
School of Physics, Zhejiang University, 310027, Hangzhou, Zhejiang, China.
CAS Key Laboratory of Theoretical Physics and Institute of Theoretical Physics, Chinese Academy of Sciences, 100190, Beijing, China.
Nat Commun. 2024 Feb 27;15(1):1775. doi: 10.1038/s41467-024-46078-1.
Understanding fluctuation phenomena plays a dominant role in the development of many-body physics. The time evolution of entanglement is essential to a broad range of subjects in many-body physics, ranging from exotic quantum matter to quantum thermalization. Stemming from various dynamical processes of information, fluctuations in entanglement evolution differ conceptually from out-of-equilibrium fluctuations of traditional physical quantities. Their studies remain elusive. Here we uncover an emergent random structure in the evolution of the many-body wavefunction in two classes of integrable-either interacting or noninteracting-lattice models. It gives rise to out-of-equilibrium entanglement fluctuations which fall into the paradigm of mesoscopic fluctuations of wave interference origin. Specifically, the entanglement entropy variance obeys a universal scaling law in each class, and the full distribution displays a sub-Gaussian upper and a sub-Gamma lower tail. These statistics are independent of both the system's microscopic details and the choice of entanglement probes, and broaden the class of mesoscopic universalities. They have practical implications for controlling entanglement in mesoscopic devices.
理解涨落现象在多体物理的发展中起着主导作用。纠缠的时间演化对于多体物理中的广泛主题至关重要，从奇异量子物质到量子热化。源于各种信息动力学过程，纠缠演化中的涨落在概念上不同于传统物理量的非平衡涨落。对它们的研究仍然难以捉摸。在这里，我们在两类可积（相互作用或非相互作用）晶格模型的多体波函数演化中发现了一种涌现的随机结构。它导致了非平衡纠缠涨落，这些涨落属于波干涉起源的介观涨落范式。具体而言，纠缠熵方差在每一类中都遵循一个普遍的标度律，并且完整分布显示出亚高斯上尾和亚伽马下尾。这些统计特性与系统的微观细节和纠缠探针的选择无关，并拓宽了介观普遍性的类别。它们对于控制介观器件中的纠缠具有实际意义。
