时间：2022年6月25日

地点：数学院南楼 N208

中国科学院数学与系统科学研究院

 

题　目：Reflected Entropy in Double Holography

报告人：凌意  研究员 (中科院高能物理所)

时　间：2022年6月25日10:00-11:00

摘　要：Recently, the reflected entropy is proposed in holographic approach to describe the entanglement of a bipartite quantum system in a mixed state, which is identified as the area of the reflected minimal surface inside the entanglement wedge. In this paper, we study the reflected entropy in the doubly holographic setup, which contains the degrees of freedom of quantum matter in the bulk. In this context, we propose a notion of quantum entanglement wedge cross-section, which may describe the reflected entropy with higher-order quantum corrections. We numerically compute the reflected entropy in pure AdS background and black hole background in four dimensions, respectively. In general, the reflected entropy contains the contribution from the geometry on the brane and the contribution from the CFT. We compute their proportion for different Newton constants and find that their behaviors are in agreement with the results based on the semi-classical gravity and the correlation of CFT coupled to the bath CFT.

 

题　目：Dynamical transitions in scalarization and descalarization through black hole accretion 

报告人：田雨  教授 (国科大物理学院)

时　间：2022年6月25日11:00-12:00

摘　要：We present the first fully nonlinear study on the accretion of scalar fields onto a seed black hole in anti-de Sitter spacetime in Einstein-Maxwell-scalar theory. Intrinsic critical phenomena in the dynamical transition between the bald and scalarized black holes are disclosed. In scalarizations, the transition is discontinuous and a metastable black hole acts as an attractor at the threshold. We construct a new physical mechanism to dynamically descalarize an isolated scalarized black hole. The first results on critical phenomena in descalarizations are revealed. The dynamical descalarizations can be either discontinuous or continuous at the threshold, distinguished by whether or not an attractor appears.

 

题　目：Holographic Einstein Ring of a Charged AdS Black Hole 

报告人：张宏宝  副教授 (北师大物理系)

时　间：2022年6月25日14:00-15:00

摘　要：The Einstein ring of a charged AdS black hole is presented in the framework of holography. As an oscillating Gaussian source setting on the AdS boundary propagates in the bulk, we employ the response function to detect it, and find the response function, with the help of wave optics, can produce the Einstein ring. We also investigate the effect of the charge of black hole on the ring. Our result shows that as the charge increases, the radius of the ring enlarges. In addition, we find the Einstein ring can also be given by the damping modes in bulk since the response function is related to the Green function, whose poles correspond to the quasi-normal frequency in the gravity side.