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DTSTART;TZID=America/New_York:20250414T150000
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DTSTAMP:20260730T174229
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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
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CREATED:20241209T163821Z
LAST-MODIFIED:20250410T204704Z
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SUMMARY:Quantum K-theory at roots of unity
DESCRIPTION:Colloquium \nSpeaker: Andrey Smirnov\, University of North Carolina at Chapel Hill \nTitle: Quantum K-theory at roots of unity \nAbstract: In this talk\, I will discuss a version of quantum K-theory introduced by A.Okounkov\, which can be defined through quasimap counts. In this framework\, the quantum K-theory ring is obtained as a specialization of the equivariant quasimap count at $q=1$\, where $q$ is the equivariant parameter associated with the torus action on the source of the quasimaps. A related\, but less explored\, structure emerges when $q$ is specialized at the roots of unity. I will outline the key ideas behind this construction and its implications. As an application\, I’ll also describe the spectrum of $p$-curvature for the quantum connection\, which offers a new proof of a recent result by P.Etingof and A.Varchenko. This talk is based on joint work with P. Koroteev.
URL:https://cmsa.fas.harvard.edu/event/colloquium-41425/
LOCATION:CMSA Room G10\, CMSA\, 20 Garden Street\, Cambridge\, MA\, 02138\, United States
CATEGORIES:Colloquium
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