时间：9月23日（周一）14:00

地点：勤园20-518

报告摘要：

We derive corrections to the sub-leading logarithmic term of the entanglement entropy in systems with spontaneous broken continuous symmetry. Using quantum Monte Carlo simulations, we show that the improved scaling formula leads to much better estimations of the number of Goldstone modes in the two-dimensional square lattice spin-1/2 Heisenberg model and bilayer spin-1/2 Heisenberg model in systems of rather small sizes, compared with previous results. Furthermore, we study the scaling behavior of the Rényi entanglement entropy with smooth boundaries at the putative deconfined critical point separating the Néel antiferromagnetic and valence-bond-solid states of the two-dimensional J-Q3 model. By using our improved scaling formula, we observe a sub-leading logarithmic term with a coefficient indicating the presence of four Goldstone modes, signifying the presence of an SO(5) symmetry at the transition point, which spontaneously breaks into an O(4) symmetry in the thermodynamic limit. This result supports the conjecture that an SO(5) symmetry emerges at the transition point, but reveals the transition to be weakly first-order. Thus, we demonstrate a novel approach to detect emergent continuous symmetry and, more importantly, identify weakly first-order phase transitions efficiently, which have been notoriously challenging for conventional methods.

报告人简介：

邓泽辉，北京计算科学研究中心博士后。2011年进入北京师范大学物理学系，攻读理论物理专业统计物理方向，2016年获得理学博士学位。主要研究方向低维量子体系中的新奇物态与量子相变、量子多体纠缠。近期分别在Physical Review Letters 和Physical Review B上发表了最新的研究进展。