报告题目：Topological and Trivial Valence-Bond Orders in Higher-Spin Kitaev Models
报告时间：2026年4月8日星期三10:00
报告地点：物理楼329会议室
报告人：Dr. Yuchi He
邀请人：邹海源 研究员
报告人单位：Ghent University
报告人简介：
Yuchi He obtained his PhD in the physics department of Carnegie Mellon University, USA in 2020. Before that, he earned his BS from Peking University. He worked as a postdoc at RWTH Aachen University and the University of Oxford. Now he is a postdoc at Ghent University and a visiting researcher at Oxford. His primary research interest is phases and dynamics of strongly correlated quantum many-body systems. One-dimensional and two-dimensional systems are investigated by applying and developing effective theory and tensor network methods. Most recently, he has been interested in twisted transition metal dichalcogenides and frustrated magnetism.
报告摘要：
We boost the performance of gradient optimization of (dense) iPEPS to D>10 and chi>500. Combining novel data analysis techniques, we find a new phase of matter in Kitaev type of frustrated magnets: spontaneous valence-bond solid with topological order. We investigate the quantum phases of higher-spin Kitaev models using tensor network methods. Our results reveal distinct bond-ordered phases for spin-1, spin- 3/2, and spin-2 models. In all cases, we find translational symmetry breaking with unit cells being tripled by forming valence-bond orders. However, these three phases are distinct, forming plaquette order, topological dimer order, and non-topological dimer order, respectively. Our findings are based on a cross-validation between variational two-dimensional tensor network calculations: an unrestricted exploration of symmetry-broken states versus the detection of symmetry breaking from cat-state behavior in symmetry-restricted states. The origin of different orders can also be understood from a theoretical analysis. Our work sheds light upon the interplay between topological and symmetry-breaking orders as well as their detection via tensor networks. Our improvement of VUMPS algorithm and gradient descent method will be discussed.