Speaker: Yang Qi (Fudan University)
Abstract: Symmetry-protected topological (SPT) phases are quantum states of matter beyond the Landau paradigm of classifying phases by symmetry breaking. Mathematically, the classification of such SPT phases are described as generalized cohomology theories. In this talk, I will first give a brief review of the SPT phases and how to classify them using the cohomology of groups. Then I will discuss two recent works on computing the classification of SPT phases: First, the interacting-fermion SPT states can be classified using an Atiyah-Hirzebruch Spectral Sequence, and we are working on a software package that computes this spectral sequence automatically. Second, we classify crystalline-symmetry-protected topological phases using a spectral sequence, which can be viewed as a recipe for real-space constructions of such topological phases.
Time: 13:30-14:30, Friday, 20th December, 2024
Location: Room 1410, SIMIS, Block A, No. 657 Songhu Road, Yangpu District, Shanghai
Send comments or questions to: Miguel Tierz (Seminar organizer) to tierz at simis.cn
Biography of the speaker: Dr. Yang Qi received his Ph.D. from Harvard University in 2010. He was an associate researcher in Institute for Advanced Study, Tsinghua University from 2010 to 2014, a visiting scholar at Perimeter Institute from 2014 to 2016, and a postdoc at MIT from 2016 to 2017. He joined Fudan University as a Researcher in 2017, and he was appointed as a “Xie Xide” Junior Chair Professor in 2022. Dr. Qi mainly works in the direction of theoretical studies of strongly correlated quantum many-body systems, including classification of topological phases, frustrated quantum magnets and quantum spin liquids.
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