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DTSTART;TZID=America/New_York:20250127T150000
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DTSTAMP:20260504T211234
CREATED:20240907T194212Z
LAST-MODIFIED:20250124T171827Z
UID:10003471-1737990000-1737993600@cmsa.fas.harvard.edu
SUMMARY:A homotopy of 2d SCFTs and an implication for Topological Modular Forms
DESCRIPTION:Quantum Field Theory and Physical Mathematics Seminar \nSpeaker: Vivek Saxena (YITP Stony Brook and NHETC Rutgers) \nTitle: A homotopy of 2d SCFTs and an implication for Topological Modular Forms \nAbstract: The Segal-Stolz-Teichner conjecture states that there exists an isomorphism between deformation classes of two-dimensional N=(0\,1) superconformal field theories (SCFTs) and generalized cohomology classes known as Topological Modular Forms (TMFs). Such 2d N=(0\,1) SCFTs arise naturally in physics as worldsheet theories of (possibly compactified) heterotic strings. Recently\, this connection was used to prove the absence of global anomalies in heterotic string theories and make predictions about topological terms in their low-energy effective actions\, among other things. \nIn this talk\, after giving a brief overview of these ideas\, I will describe a physics ”proof” (using methods from 2d CFT) of a mathematical conjecture of Tachikawa and Yamashita about TMF classes in degree 31. Specifically\, by examining the two worldsheet theories corresponding to two T-dual nine-dimensional spacetime non-supersymmetric heterotic string theories (namely the $(E_8)_1 \times (E_8)_1$ theory and the $(E_8)_2$ theory)\, I will argue that the $(E_8)_2$ theory corresponds to the unique nontrivial torsion element $[(E_8)_2]$ of TMF$^{31}$ with zero mod-2 elliptic genus.
URL:https://cmsa.fas.harvard.edu/event/qft_12725/
LOCATION:CMSA Room G10\, CMSA\, 20 Garden Street\, Cambridge\, MA\, 02138\, United States
CATEGORIES:Quantum Field Theory and Physical Mathematics
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