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DTSTART;TZID=America/New_York:20250407T150000
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DTSTAMP:20260417T062622
CREATED:20250128T192454Z
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UID:10003694-1744038000-1744041600@cmsa.fas.harvard.edu
SUMMARY:Quantum Field Theory and Physical Mathematics
DESCRIPTION:Quantum Field Theory and Physical Mathematics Seminar \nSpeaker: Matthew Yu (Oxford) \nTitle: A new tangential structure for type IIA string theory \nAbstract: The Green-Schwarz anomaly cancellation condition says that the target space of heterotic string theory must come with a string structure for the theory to be consistent. In this talk we discuss a new tangential structure called string^h\, first introduced by Devalapurkar\, as a spin^c analogue of string. Approximating the correct tangential structure of string theory has many implications\, primarily is the Swampland program via the cobordism conjecture of Mcnamara and Vafa. We will show that the spectrum of string^h has the notable property that it orients tmf_1(n)\, just like how the spectrum of string orients tmf\, by the work of Ando-Hopkins-Rezk. Finally we will show that the anomaly condition of the partition function of M-theory\, studied by Diaconescu-Moore-Witten is implied by a string^h structure on the target space of type IIA\, in parallel to the Green-Schwarz anomaly for heterotic string theory\, and discuss applications for anomaly cancellation.
URL:https://cmsa.fas.harvard.edu/event/qft_4725/
LOCATION:CMSA Room G10\, CMSA\, 20 Garden Street\, Cambridge\, MA\, 02138\, United States
CATEGORIES:Quantum Field Theory and Physical Mathematics
ATTACH;FMTTYPE=image/png:https://cmsa.fas.harvard.edu/media/CMSA-QFT-and-Physical-Mathematics-4.7.25.png
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DTSTART;TZID=America/New_York:20250414T150000
DTEND;TZID=America/New_York:20250414T160000
DTSTAMP:20260417T062622
CREATED:20250128T192515Z
LAST-MODIFIED:20250409T174327Z
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SUMMARY:The Extended Vertex Algebra of 4d N = 2 SCFTs and their Higher Products
DESCRIPTION:Quantum Field Theory and Physical Mathematics Seminar \nSpeaker: Mitch Weaver\, KAIST \nTitle: The Extended Vertex Algebra of 4d N = 2 SCFTs and their Higher Products \nAbstract: Every 4d N=2 superconformal field theory contains a BPS protected sub-algebra of local operators that has the structure of a vertex operator algebra (VOA). This VOA is identified by passing to the cohomology of a nilpotent supercharge\, T\, whose local operator cohomology is represented by twist-translated Schur operators with support in a Euclidean two-plane. When working in 4d Minkowski space\, this cohomology admits a web of three extended operators (called descent operators) that are constructed from each Schur operator in the VOA\, have worldvolume support in the Lorentzian two-plane that is transverse to the Euclidean plane supporting the VOA\, and behave as point-like insertions in the plane of the VOA\, i.e. as new chiral operators. The combined result is the extended vertex algebra (EVA): a universal extension of the VOA that canonically has the structure of a quasi-VOA\, i.e. a vertex algebra (VA) with no conformal vector but which still possesses a representation of sl(2). After reviewing the VOA of Schur operators\, I will explain the origin of the descent operators and present the OPEs for a subsector of the EVA in the free hyper SCFT.\nTime permitting\, I will also describe the construction and basic properties of a set of higher products that are associated to each descent operator. Such products function as higher dimensional versions of 2d chiral algebra λ-brackets\, i.e. positive mode operators: they are defined on the EVA and map to the operators appearing in the singular terms of OPEs involving descent operators. Their existence offers a route toward sl(2) symmetry enhancement of the EVA and suggests the latter has structural properties that are common to the higher dimensional chiral algebras describing the minimal twists of 3d N = 2 and 4d N = 1 SQFTs. This talk is based on [2211.04410] and forthcoming work.
URL:https://cmsa.fas.harvard.edu/event/qft_41425/
LOCATION:Hybrid – G10
CATEGORIES:Quantum Field Theory and Physical Mathematics
ATTACH;FMTTYPE=image/png:https://cmsa.fas.harvard.edu/media/CMSA-QFT-and-Physical-Mathematics-4.14.25.png
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