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X-WR-CALDESC:Events for CMSA
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DTSTART;TZID=America/New_York:20241120T150000
DTEND;TZID=America/New_York:20241120T160000
DTSTAMP:20241115T183220Z
CREATED:20241010T135347Z
LAST-MODIFIED:20241115T183220Z
UID:10003593-1732114800-1732118400@cmsa.fas.harvard.edu
SUMMARY:A new construction of c = 1 conformal blocks
DESCRIPTION:Mathematical Physics and Algebraic Geometry Seminar \nSpeaker: Qianyu Hao\, University of Geneva \nTitle: A new construction of c = 1 conformal blocks\n\nAbstract: The Virasoro conformal blocks are very interesting since they have many connections to other areas of math and physics. For example\, when c = 1\, they are related to tau functions of Painlevé equations. I will first explain what Virasoro conformal blocks are. Then I will describe a new way to construct Virasoro blocks at c = 1 on C by using the “abelian” Heisenberg conformal blocks on a branched double cover of C. The main new idea in our work is to use a spectral network. It is closely related to the idea of nonabelianization of the flat connections in the work of Gaiotto-Moore-Neitzke and Neitzke-Hollands. This nonabelianization construction enables us to compute the harder-to-get Virasoro blocks using the simpler abelian objects. This is based on a joint work with Andrew Neitzke.
URL:https://cmsa.fas.harvard.edu/event/mathphys_112024/
LOCATION:CMSA Room G10\, CMSA\, 20 Garden Street\, Cambridge\, MA\, 02138\, United States
CATEGORIES:Mathematical Physics and Algebraic Geometry
ATTACH;FMTTYPE=image/png:https://cmsa.fas.harvard.edu/media/CMSA-Mathematical-Physics-and-Algebraic-Geometry-11.20.2024.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20241114T100000
DTEND;TZID=America/New_York:20241114T110000
DTSTAMP:20241112T151542Z
CREATED:20241107T191256Z
LAST-MODIFIED:20241112T151542Z
UID:10003598-1731578400-1731582000@cmsa.fas.harvard.edu
SUMMARY:(Un)likely intersections
DESCRIPTION:Mathematical Physics and Algebraic Geometry Seminar \nSpeaker: Tom Scanlon\, UC Berkeley \nTitle: (Un)likely intersections\n\nAbstract: The Zilber-Pink conjectures predicts that for an ambient special variety  (such as an abelian variety or a Shimura variety)\, if   is an irreducible algebraic subvariety which is not contained a proper special subvariety of  (e.g. a proper algebraic subgroup in the abelian variety case or a variety of Hodge type in the case of Shimura varieties)\, then the union of the unlikely intersections  as  ranges over the special subvarieties of  with  is not Zariski dense in .  While various instances of this conjecture have been proven\, it remains open in most cases of interest.  In this lecture\, I will describe some of my work with Jonathan Pila in which we prove an effective function field version of this conjecture along with a counterpart to the Zilber-Pink conjecture proven with Sebastian Eterović:  after accounting for some geometric obstructions\, the likely intersections\, i.e. the union of the intersections  with  special and \,  are dense in the Euclidean topology in .   Our techniques for both results come from o-minimal complex analysis and differential algebra.\n\n 
URL:https://cmsa.fas.harvard.edu/event/mathphys_111424/
LOCATION:CMSA Room G10\, CMSA\, 20 Garden Street\, Cambridge\, MA\, 02138\, United States
CATEGORIES:Mathematical Physics and Algebraic Geometry
ATTACH;FMTTYPE=image/png:https://cmsa.fas.harvard.edu/media/CMSA-Mathematical-Physics-and-Algebraic-Geometry-11.14.2024.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20241107T100000
DTEND;TZID=America/New_York:20241107T110000
DTSTAMP:20241104T171029Z
CREATED:20241104T150020Z
LAST-MODIFIED:20241104T171029Z
UID:10003597-1730973600-1730977200@cmsa.fas.harvard.edu
SUMMARY:Bounds and Dualities of Type II Little String Theories
DESCRIPTION:Mathematical Physics and Algebraic Geometry Seminar \nSpeaker: Fabian Ruehle (Northeastern University) \nTitle: Bounds and Dualities of Type II Little String Theories \nAbstract: The goal of this seminar is to introduce Type II Little String Theories (LSTs)\, which are six-dimensional supersymmetric QFTs. We explore how to geometrically engineer these theories within the context of M-/F-theory (top-down) as well as consistent QFT realizations (bottom-up). After that\, we turn to the worldsheet theory of LSTs\, which are two-dimensional N=(0\,4) SCFTs. Using anomaly inflow and unitarity\, we derive strong constraints on the rank of their global symmetry algebras.
URL:https://cmsa.fas.harvard.edu/event/mathphys_11724/
LOCATION:CMSA Room G10\, CMSA\, 20 Garden Street\, Cambridge\, MA\, 02138\, United States
CATEGORIES:Mathematical Physics and Algebraic Geometry
ATTACH;FMTTYPE=image/png:https://cmsa.fas.harvard.edu/media/CMSA-Mathematical-Physics-and-Algebraic-Geometry-11.7.2024.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20241031T100000
DTEND;TZID=America/New_York:20241031T110000
DTSTAMP:20241022T180010Z
CREATED:20241022T175333Z
LAST-MODIFIED:20241022T180010Z
UID:10003596-1730368800-1730372400@cmsa.fas.harvard.edu
SUMMARY:Mirror Construction for Nakajima Quiver Varieties
DESCRIPTION:Mathematical Physics and Algebraic Geometry Seminar \nSpeaker: Ju Tan (Boston University) \nTitle: Mirror Construction for Nakajima Quiver Varieties \nAbstract: Quiver possesses a rich representation theory. On the one hand\, it exhibits a deep connection with instantons and coherent sheaves as illuminated by the ADHM construction and the works of many others. On the other hand\, quivers also capture the formal deformation space of a Lagrangian submanifold. In this talk\, we will discuss these relations more explicitly from the perspective of SYZ mirror symmetry. In particular\, we will introduce the notion of framed Lagrangian immersions\, the Maurer-Cartan deformation spaces of which are Nakajima quiver varieties/ stacks. Besides\, we will realize the ADHM construction as a mirror symmetry phenomenon. This is based on the joint work with Jiawei Hu and Siu-Cheong Lau. \n  \n 
URL:https://cmsa.fas.harvard.edu/event/mathphys_103124/
LOCATION:CMSA Room G10\, CMSA\, 20 Garden Street\, Cambridge\, MA\, 02138\, United States
CATEGORIES:Mathematical Physics and Algebraic Geometry
ATTACH;FMTTYPE=application/pdf:https://cmsa.fas.harvard.edu/media/CMSA-Mathematical-Physics-and-Algebraic-Geometry-10.31.2024.docx.pdf
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20241024T100000
DTEND;TZID=America/New_York:20241024T110000
DTSTAMP:20241018T144254Z
CREATED:20241018T143428Z
LAST-MODIFIED:20241018T144254Z
UID:10003595-1729764000-1729767600@cmsa.fas.harvard.edu
SUMMARY:Heterotic Little String Theories and Inequivalent Genus-One Fibrations
DESCRIPTION:Mathematical Physics and Algebraic Geometry Seminar \nSpeaker: Hamza Ahmed\, Northeastern University \nTitle: Heterotic Little String Theories and Inequivalent Genus-One Fibrations \nAbstract: Little String Theories (LSTs) are 6D Supersymmetric quantum field theories (SQFTs) with an additional physical relation called T-duality. This enables us to arrange them into equivalence classes\, where each equivalence class has 6D LSTs that lead to the same 5D effective theory when compactified on a circle. The problem of finding T-dual LSTs can be mapped to the problem of finding inequivalent genus-one fibrations of the same non-compact Calabi-Yau (CY) threefold. For T-dual theories\, certain field theory data is expected to match\, which then implies certain invariants of inequivalent fibrations. Focusing on theories with 8 supercharges (Heterotic LSTs)\, we use this geometry-field theory equivalence to study the T-duality landscape\, particularly in the case where the genus-one fiber does not have a section\, leading to what are called twisted T-dual theories. Based on the excellent agreement we find between the geometry and field theory arguments\, we conjecture the existence of a new class of twisted T-duals for which no geometric construction is known. \n  \n 
URL:https://cmsa.fas.harvard.edu/event/mathphys_102424/
LOCATION:Virtual
CATEGORIES:Mathematical Physics and Algebraic Geometry
ATTACH;FMTTYPE=image/png:https://cmsa.fas.harvard.edu/media/CMSA-Mathematical-Physics-and-Algebraic-Geometry-10.24.2024.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20241003T100000
DTEND;TZID=America/New_York:20241003T110000
DTSTAMP:20240927T183006Z
CREATED:20240927T144416Z
LAST-MODIFIED:20240927T183006Z
UID:10003592-1727949600-1727953200@cmsa.fas.harvard.edu
SUMMARY:Enumerative geometry and modularity in two-modulus K3-fibered Calabi-Yau threefolds
DESCRIPTION:Mathematical Physics and Algebraic Geometry Seminar \nSpeaker: Chuck Doran\, Harvard CMSA \nTitle: Enumerative geometry and modularity in two-modulus K3-fibered Calabi-Yau threefolds \nAbstract: Smooth $M_m$-polarized K3-fibered Calabi-Yau (CY) 3-folds have been classified in terms of the choice of a generalized functional invariant and\, in the case $m=1$\, a generalized homological invariant. The resulting geometries generally exhibit a small number of complex structure moduli greater or equal to two. A concrete choice of these invariants realizes (almost all of) the known Calabi-Yau geometries with exactly two moduli and allows us to describe completely the structure of the corresponding moduli spaces. The corresponding variations of Hodge structure are entirely determined by the regular periods\, for which we obtain a generic expression in terms of $m$ and three integers $i\,j\,s$. Using the form of this period and Batyrev-Borisov mirror symmetry we explicitly construct the corresponding mirror CY 3-folds with two Kaehler moduli and show consistency with the DHT conjecture. In the cases with $s=0$\, the mirror CY 3-folds are again K3-fibered but with the mirror $<2m>$-polarization. The generic form of the periods allows us to derive generic modular expressions for the A-model topological string free energies and we argue that those are a consequence of a Tyurin degeneration of the generalized functional invariant with the central fiber being an $M_m$-polarized K3. This is joint work with Boris Pioline and Thorsten Schimannek.
URL:https://cmsa.fas.harvard.edu/event/mathphys_10324/
LOCATION:CMSA Room G10\, CMSA\, 20 Garden Street\, Cambridge\, MA\, 02138\, United States
CATEGORIES:Mathematical Physics and Algebraic Geometry
ATTACH;FMTTYPE=image/png:https://cmsa.fas.harvard.edu/media/CMSA-Mathematical-Physics-and-Algebraic-Geometry-10.3.2024.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20240926T100000
DTEND;TZID=America/New_York:20240926T110000
DTSTAMP:20240920T143613Z
CREATED:20240917T135417Z
LAST-MODIFIED:20240920T143613Z
UID:10003508-1727344800-1727348400@cmsa.fas.harvard.edu
SUMMARY:Witten deformation for non-Morse functions and gluing formulas 
DESCRIPTION:Mathematical Physics and Algebraic Geometry \nSpeaker: Junrong Yan (Northeastern University) \nTitle: Witten deformation for non-Morse functions and gluing formulas \nAbstract: Witten deformation is a versatile tool with numerous applications in mathematical physics and geometry. In this talk\, we will focus on the analysis of Witten deformation for a family of non-Morse functions\, which leads to a new technique for studying the gluing formulas of global spectral invariants (such as eta invariants\, analytic torsions\, and some invariants related to Feynman diagrams\, etc.). We will then discuss some applications of this new method. \n 
URL:https://cmsa.fas.harvard.edu/event/mathphys_92624/
LOCATION:CMSA Room G10\, CMSA\, 20 Garden Street\, Cambridge\, MA\, 02138\, United States
CATEGORIES:Mathematical Physics and Algebraic Geometry
ATTACH;FMTTYPE=image/png:https://cmsa.fas.harvard.edu/media/CMSA-Mathematical-Physics-and-Algebraic-Geometry-09.26.2024.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20240919T100000
DTEND;TZID=America/New_York:20240919T110000
DTSTAMP:20240917T155533Z
CREATED:20240917T135258Z
LAST-MODIFIED:20240917T155533Z
UID:10003507-1726740000-1726743600@cmsa.fas.harvard.edu
SUMMARY:Feynman graph integrals from topological holomorphic theories 
DESCRIPTION:Mathematical Physics and Algebraic Geometry Seminar \nSpeaker: Minghao Wang (Boston University) \nTitle: Feynman graph integrals from topological holomorphic theories \nAbstract: Feynman graph integrals from topological theories were developed by M. Kontsevich\, S. Axelrod and I. M. Singer in 1990s. These integrals have many mathematical applications\, such as knot invariants\, operad theory and formality theorems. In this talk\, I will talk about Feynman graph integrals from topological-holomorphic theories. In particular\, I will prove the finiteness of Feynman graph integrals when spacetime is flat spaces and a vanishing result of graph integrals. Combining the vanishing result with Batalin-Vilkovisky(BV) formalism\, we can show the absence of anomalies of topological-holomorphic theories on flat spaces with at least two topological dimensions. As a consequence\, we can construct factorization algebras of quantum observables. This is a joint with Brian Williams.
URL:https://cmsa.fas.harvard.edu/event/mathphys_91924/
LOCATION:CMSA Room G10\, CMSA\, 20 Garden Street\, Cambridge\, MA\, 02138\, United States
CATEGORIES:Mathematical Physics and Algebraic Geometry
ATTACH;FMTTYPE=image/png:https://cmsa.fas.harvard.edu/media/CMSA-Mathematical-Physics-and-Algebraic-Geometry-09.19.2024.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20240912T100000
DTEND;TZID=America/New_York:20240912T110000
DTSTAMP:20240917T140551Z
CREATED:20240907T170232Z
LAST-MODIFIED:20240917T140551Z
UID:10003412-1726135200-1726138800@cmsa.fas.harvard.edu
SUMMARY:Twisted Tools for (Untwisted) Quantum Field Theory
DESCRIPTION:Mathematical Physics and Algebraic Geometry \nSpeaker: Justin Kulp (Simons Center for Geometry and Physics) \nTitle: Twisted Tools for (Untwisted) Quantum Field Theory \nAbstract: One of the most important properties of QFTs is that they can be deformed by “turning on interactions.” Essentially every observable can be viewed as coupling the theory to some external system. Famously\, adding interactions (generically) breaks scale invariance\, leading to familiar ideas of EFTs and RG flows in the space of QFTs. An underappreciated fact is that one can actually consider flows generated by any transformation\, not just the usual scale transformations. \nIn my talk\, I will discuss a flow in the space of QFTs coming from (an analogue of) BRST symmetry. The beta-function for this “BRST-flow” controls deformations of the QFT and is highly mathematically constrained\, endowing the space of interactions with an L∞ algebra structure. The structure constants/brackets of the L∞ algebra are highly computable (requiring only a first course in QFT to compute) and contain familiar information such as anomalies and Operator Product Expansion coefficients. I will prove a non-renormalization theorem for holomorphic-topological QFTs with more than one topological direction\, which can be thought of as a generalization of a formality theorem of Kontsevich. Time permitting\, I will discuss how this formalism enables the systematic computation of minimal BPS operators in supersymmetric QFTs and describe the “holomorphic confinement” of N=1 SYM.  Based on arXiv:2403.13049.
URL:https://cmsa.fas.harvard.edu/event/mathphys_91224/
LOCATION:CMSA Room G10\, CMSA\, 20 Garden Street\, Cambridge\, MA\, 02138\, United States
CATEGORIES:Mathematical Physics and Algebraic Geometry
ATTACH;FMTTYPE=image/png:https://cmsa.fas.harvard.edu/media/CMSA-Mathematica-Physics-and-Algebraic-Geometry-09.12.2024.png
END:VEVENT
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