*2019年 [#le173fee] ***[[Seminar]] [#b85254f3] 日時: May 15 (Wed.) 15:00-16:00 場所: D413 講演者: Kotaro Tamaoka (YITP) タイトル: A Generalization of the Entanglement Entropy and Holography 概要: We define a new information theoretic quantity called odd entanglement entropy (OEE) which enables us to compute the entanglement wedge cross section in holographic CFTs. The entanglement wedge cross section has been introduced as a minimal cross section of the entanglement wedge, a natural generalization of the Ryu-Takayanagi surface. First, we review basic ingredients in order to define the OEE. Then, we will explain some basic properties of the OEE. Finally, we explicitly compute the generalized entropy for mixed states in two-dimensional holographic CFT and see agreement with the entanglement wedge cross section. This talk is based on 1809.09109 (Phys. Rev. Lett. 122, 141601). -[http://www-het.ph.tsukuba.ac.jp/Seminar/tsukuba-only/2019/seminar20190515_Tamaoka.pdf 2019/5/15:slides(pdf)] ***[[Seminar]] [#b85254f3] 日時: April 11 (Thr.) 15:00-16:00 場所: Workshop room at CCS 講演者: Sato Yuki (Nagoya Univ.) タイトル: How to "cool down" Ising model on 2d dynamical triangulations 概要: The Ising model on 2d dynamical triangulations was originally introduced by Kazakov in 1986, which is a statistical system including gravitational degrees of freedom. This system is known to be critical at the finite temperature and the continuum theory defined around the critical point is the 2d gravity minimally coupled to fermions. We introduce an external parameter to the system, aiming at observing the quantum critical behavior. Tuning the parameter to a certain value the critical temperature reaches absolute zero and the resulting continuum theory at the zero temperature is NOT the 2d gravity minimally coupled to fermions. As it turns out, physics at the zero-temperature may differ depending on the "cool down speed". The talk will be based on the work with Tomo Tanaka (Phys.Rev. D98 (2018) no.2, 026026) and the work in progress with Jan Ambjorn. -[http://www-het.ph.tsukuba.ac.jp/Seminar/tsukuba-only/2019/seminar20190411_Sato.pdf 2019/4/11:slides(pdf)]