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报告题目：The fine structure of the entanglement entropy in the O(2) model

报 告 人：杨丽平 重庆大学

报告时间：2016年7月11日（星期一）上午10:00

报告地点：格致楼5004报告厅

报告摘要：

We compare two calculations of the particle density in the superfluid phase of the classical XY model with a chemical potential $mu$ in 1+1 dimensions.The first relies on exact blocking formulas fromthe Tensor Renormalization Group (TRG) formulation of the transfer matrix. The second is a worm algorithm. We show that the particle number distributions obtained with the two methods agree well. We use the TRG method to calculate the thermal entropy andthe entanglement entropy. We describe the particle density, the two entropies and the topology of the world lines as we increase $mu$ to go across the superfluid phase between the first two Mott insulating phases.For a sufficiently large temporal size, this process reveals an interesting fine structure: the average particle number and the winding number of most of the world lines in the Euclidean time direction increase by one unit at a time. At each step, the thermal entropy develops a peak and the entanglement entropy increases until we reach half-filling and then decreases in a way that approximately mirror the ascent. This suggests an approximate fermionic picture.

报告人简介：

杨丽平，重庆大学讲师。2009年博士毕业于中国科学院理论物理研究所，随后赴日本，荷兰，德国进行访问研究和博士后工作，2012年入职重庆大学。入职后在瑞士，日本，北京，合肥等地进行学术交流与访问。在国际知名期刊（PRL，PR系列，JPCM等）发表文章10余篇，文章引用超过150次。在国内外学术会议上报告十余次。主要研究方向：经典/量子格点模型，量子相变，转移矩阵方法，张量重正化群算法。