报告题目：Complexity growth of operators in the SYK model and in JT gravity 

报告人：冼卓宇   博士（中国科学院理论物理研究所）

报告时间：2020 年 11 月 19 日（周四）15：30          

报告地点：在线报告（ 腾讯会议 ID : 537 4946 4937）

报告摘要：

The concepts of operator size and complexity can statistically characterize the growth of Heisenberg operators. Here we study partially entangled thermal states in the Sachdev-Ye-Kitaev (SYK) model and their dual description in terms of operators inserted in the interior of a black hole in Jackiw-Teitelboim (JT) gravity. We compare a microscopic definition of complexity in the SYK model known as Krylov-complexity to the volume-complexity in JT gravity and find that both quantities show an exponential-to-linear growth behavior. We also calculate the growth of operator size under time evolution and find connections between size and complexity. While the notion of operator size saturates at the scrambling time, our study suggests that complexity, which is well defined in both quantum systems and gravity theories, can serve as a useful measure of operator evolution at both early and late times.

报告人简介：冼卓宇，2009年-2013年在华南理工大学获得学士学位；2013年-2018年在中国科学院高能物理研究所获得博士学位；2018年-2020年在中国科学院理论物理研究所从事博士后研究工作。其主要研究方向为反德西特时空/凝聚态理论对应（AdS/CMT）和Sachdev-Ye-Kitaev模型中的相变、输运和纠缠。已在国内外学术期刊PRL, JHEP, PRB上发表论文10篇。