新闻内容：
报 告 人: 唐维 博士（北京大学）
邀请人：杨丽平
时 间： 2018年5月17号（星期四）下午2:00
地点：物理学院LE201（理论物理平台）
Abstract : Recently, entropy corrections on nonorientable manifolds such as the Klein bottle are proposed as a universal characterization of critical systems with an emergent conformal field theory (CFT). We show that entropy corrections on the Klein bottle can be interpreted as a boundary effect via transforming the Klein bottle into an orientable manifold with nonlocal boundary interactions, based on which we propose an efficient quantum Monte Carlo (QMC) method to extract such universal boundary entropies. For rational CFTs, we perform the QMC simulation in the quantum q-state Potts model with q=2; 3; 4 and compare the calculation results with the CFT predictions. Beyond the rational CFT, we prove that in the compactified boson CFT, when the square of the compactification radius is not a rational number, the universal Klein bottle entropy still exists, and it depends only on the compactification radius. To verify this CFT prediction, we perform QMC simulations in the XXZ model and compare the numerical results with the CFT predictions. Due to the direct connection between the compactification radius and the Luttinger parameter, the relation between the compactification radius and the Klein bottle entropy also provides a new method to extract the Luttinger parameter from lattice models.
References:
[1] Hong-Hao Tu, Phys. Rev.Lett. 119, 261603 (2017).
[2] Wei Tang, Lei Chen, Wei Li, X. C. Xie, Hong-Hao Tu, and Lei Wang, Phys. Rev. B, 96, 115136(2017), Editors' suggestion.
[3] Wei Tang, X. C. Xie, Lei Wang, and Hong-Hao Tu, arXiv:1805.01300 (2018).
About the speaker:
Wei Tang received the B.S. degree from Nanjing University in 2016. Now he is a Ph.D. student at the international center for quantum materials of Peking University.
