Landau-Ginzburg Paradigm of Topological Phases
演讲者
Yu Zhao
时间
2025年06月11日 14:00 至 15:00
地点
A3-3-201
线上
Zoom 482 240 1589
(BIMSA)
摘要
Topologically ordered matter phases have been regarded as beyond the Landau-Ginzburg symmetry breaking paradigm of matter phases. Recent studies of anyon condensation in topological phases, however, may fit topological phases back in the Landau-Ginzburg paradigm. To truly do so, we realized that the string-net model of topological phases is in fact an effective lattice gauge theory coupled with anyonic matter once two modifications are made: (1) We reinterpret anyons as matter fields coupled to lattice gauge fields, thus extending the HGW model to a genuine Hamiltonian lattice gauge theory. (2) By explicitly incorporating the internal degrees of freedom of anyons, we construct an enlarged Hilbert space that supports well-defined gauge transformations and covariant coupling, restoring the analogy with conventional lattice gauge field theory. In this modified string-net model, topological phase transitions induced by anyon condensation and their consequent phenomena, such as order parameter fields, coherent states, Goldstone modes, and gapping gauge degrees of freedom, can be formulated as Landau's effective theory of the Higgs mechanism. To facilitate the understanding, we also compare anyon condensation to/with the Higgs boson condensation in the electroweak theory and the Cooper pair condensation.
演讲者介绍
Yu Zhao holds a B.Sc. in Physics from Fudan University and is currently a Ph.D. candidate in theoretical physics at Fudan under the supervision of Prof. Yidun Wan. His research focuses on exactly solvable models and the gauge structures of topological orders. He has authored five peer-reviewed papers in journals such as JHEP. He is now seeking a postdoctoral position.