Exotic emergences in low-dimensional quantum Ising models: From E_8 to D_8^((1)) particles

报告摘要：When the transverse-field Ising chain (TFIC) at its quantum critical point is perturbed by a longitudinal field along Ising spin direction, it emerges as an integrable model containing eight particles with their scattering matrices and mass spectrum organized by the exceptional E8 Lie algebra. If it weakly couples with the other quantum critical Ising chain but without the longitudinal field, then the weak inter-chain coupling can drive the system to emerge as another integrable model with eight particles, organized by the D_8^((1)) Lie algebra. Either way, realizing the quantum criticality of the TFIC is a key step to access the two exotic integrable systems. In my talk, I will explore the quantum criticality of the TFIC and its role in identifying materials hosting TFIC quantum criticality and exotic E8 physics. My journey began with an inelastic neutron scattering experiment on CoNb2O6, sparking my exploration of E8 physics. Despite a ten-year gap, recent THz spectroscopy on the same material reignited my interest, leading us to challenge the E8 paradigm and propose the D_8^((1)) picture. I will discuss why the D_8^((1)) physics provides a comprehensive understanding for the experimental observations. Along the course, we also surprisingly found long-life-time dark particle, a special kind of many-body magnetic excitation, in the integrable system which accommodates the D_8^((1)) physics.
报告人简介：吴建达，李政道学者。长期致力于量子相变、量子临界热力学及动力学、贝特拟设及可积系统动力学等相关领域的研究工作。2004年及2007年于中国科学技术大学获得学士及硕士学位、2014年博士毕业于美国莱斯大学、2014-2017年在美国加州大学圣地亚哥分校从事博士后工作、2017-2018年担任德国马普复杂系统物理所客座研究员。2018年至今就职于上海交通大学李政道研究所及物理与天文学院。迄今已在包括PRL、Nature及Nature子刊等在内的高水平学术期刊上共发表论文三十余篇。先后在国际及国内重要学术会议、国内外科研机构及学术单位给邀请学术报告六十余次。