近日，中国科学技术大学的彭新华及其研究小组与清华大学的翟荟以及复旦大学的张鹏飞等人合作并取得一项新进展。经过不懈努力，他们揭示随机相互作用自旋模型中的涌现普适猝灭动力学。相关研究成果已于2024年10月14日在国际知名学术期刊《自然—物理学》上发表。

该研究团队报道了通过在固态核磁共振系统中监测自旋去极化过程对普适动力学的实验观察，该系统由一组随机相互作用的自旋描述。自旋去极化可与高温下的时间自旋-自旋相关函数相关联。研究人员发现，这些相关函数遵循一种普适的函数形式。

这一发现有助于研究人员确定自旋去极化动力学中导致普适性的主要相互作用过程。这一观察结果表明，即使在高温下的非平衡动力学中，也存在普适性，从而补充了低能物理中已确立的普适性。

据悉，尽管量子多体系统在微观层面存在差异，但其低能平衡态物理中往往会出现普适行为。近年来，人们对研究量子多体系统远离平衡态的动力学越来越感兴趣。这种动力学通常涉及超出传统低能理论描述范围的高激发态。当前研究的主题是，在这种非平衡动力学中是否也会出现普适性。

附：英文原文

Title: Emergent universal quench dynamics in randomly interacting spin models

Author: Li, Yuchen, Zhou, Tian-Gang, Wu, Ze, Peng, Pai, Zhang, Shengyu, Fu, Riqiang, Zhang, Ren, Zheng, Wei, Zhang, Pengfei, Zhai, Hui, Peng, Xinhua, Du, Jiangfeng

Issue&Volume: 2024-10-14

Abstract: Universal behaviour often emerges in the low-energy equilibrium physics of quantum many-body systems, despite their microscopic differences. Recently, there has been a growing interest in studying the far-from-equilibrium dynamics of quantum many-body systems. Such dynamics usually involve highly excited states beyond the traditional low-energy theory description. Whether universality can also emerge in such non-equilibrium dynamics is the subject of current research. Here, we report the experimental observation of universal dynamics by monitoring the spin depolarization process in a solid-state nuclear magnetic resonance system, described by an ensemble of randomly interacting spins. The spin depolarization can be related to temporal spin–spin correlation functions at high temperatures. We discover that these correlation functions obey a universal functional form. This finding helps us identify the dominant interacting processes in the spin depolarization dynamics that lead to universality. Our observation demonstrates the existence of universality even in non-equilibrium dynamics at high temperatures, thereby complementing the well-established universality in low-energy physics.

DOI: 10.1038/s41567-024-02664-0

Source: https://www.nature.com/articles/s41567-024-02664-0