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BEGIN:VEVENT
DTSTART;TZID=America/New_York:20250429T161500
DTEND;TZID=America/New_York:20250429T181500
DTSTAMP:20260607T065147
CREATED:20250414T213151Z
LAST-MODIFIED:20250428T143404Z
UID:10003740-1745943300-1745950500@cmsa.fas.harvard.edu
SUMMARY:Algebraic approach to the bow construction
DESCRIPTION:Geometry and Quantum Theory Seminar \nSpeakers: Anadil Saeed Rao (Northeastern) and Vasily Krylov (CMSA/Harvard) \nTitle: Algebraic approach to the bow construction \nAbstract: Anadil will finish his part of the talk. Vasily will then explain how to understand moduli spaces of instantons on R^4\, monopoles on R^3\, and instantons on Taub-NUT spaces algebraically as so-called bow varieties. We will see how affine type A Nakajima quiver varieties and Slodowy slices arise as special cases of bow varieties. Time permitting\, we will also discuss applications to 3D mirror symmetry and Coulomb branches.
URL:https://cmsa.fas.harvard.edu/event/quantumgeo_42925-2/
LOCATION:Science Center 507\, 1 Oxford Street\, Cambridge\, 02138
CATEGORIES:Geometry and Quantum Theory Seminar
ATTACH;FMTTYPE=image/png:https://cmsa.fas.harvard.edu/media/CMSA-Geometry-Quantum-Theory-4.29.2025.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20250502T120000
DTEND;TZID=America/New_York:20250502T130000
DTSTAMP:20260607T065147
CREATED:20241211T195435Z
LAST-MODIFIED:20250428T151202Z
UID:10003650-1746187200-1746190800@cmsa.fas.harvard.edu
SUMMARY:Incentives for data sharing in federated learning
DESCRIPTION:Member Seminar \nSpeaker: Han Shao\, Harvard CMSA \nTitle: Incentives for data sharing in federated learning \nAbstract: Federated learning has recently emerged as a powerful approach for enabling collaboration across large populations of learning agents. However\, agents may have incentives to defect from the collaboration—that is\, to withdraw or contribute less data than expected—due to the costs of data curation and privacy concerns. This raises several key questions: What happens when agents defect\, and how can we prevent such defections? \n 
URL:https://cmsa.fas.harvard.edu/event/member-seminar-5225/
LOCATION:CMSA Room G10\, CMSA\, 20 Garden Street\, Cambridge\, MA\, 02138\, United States
CATEGORIES:Member Seminar
ATTACH;FMTTYPE=image/png:https://cmsa.fas.harvard.edu/media/CMSA-Member-Seminar-5.2.25.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20250505T150000
DTEND;TZID=America/New_York:20250505T160000
DTSTAMP:20260607T065147
CREATED:20250226T173940Z
LAST-MODIFIED:20250226T173940Z
UID:10003715-1746457200-1746460800@cmsa.fas.harvard.edu
SUMMARY:Quantum Field Theory and Physical Mathematics
DESCRIPTION:Quantum Field Theory and Physical Mathematics Seminar
URL:https://cmsa.fas.harvard.edu/event/qft_5525/
LOCATION:CMSA Room G10\, CMSA\, 20 Garden Street\, Cambridge\, MA\, 02138\, United States
CATEGORIES:Quantum Field Theory and Physical Mathematics
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20250505T163000
DTEND;TZID=America/New_York:20250505T173000
DTSTAMP:20260607T065147
CREATED:20250407T140808Z
LAST-MODIFIED:20250501T134436Z
UID:10003733-1746462600-1746466200@cmsa.fas.harvard.edu
SUMMARY:Thinking Outside the Ballot Box
DESCRIPTION:Colloquium \nSpeaker: Ariel Procaccia\, Harvard University \nTitle: Thinking Outside the Ballot Box \nAbstract: How should one design unprecedented democratic processes capable of handling enormous sets of alternatives like all possible policies\, bills\, or statements? I argue that this challenge can be addressed through a framework called generative social choice\, which fuses the rigor of social choice theory with the flexibility and power of large language models. I then explore an application of generative social choice to the problem of identifying a proportionally representative slate of opinion statements. This includes a discussion of desired properties\, an algorithm that provably achieves them\, an implementation using GPT\, and insights from an end-to-end pilot. By providing guarantees\, generative social choice could alleviate concerns about AI-driven democratic innovation and help unlock its potential.
URL:https://cmsa.fas.harvard.edu/event/colloquium-5525/
LOCATION:CMSA Room G10\, CMSA\, 20 Garden Street\, Cambridge\, MA\, 02138\, United States
CATEGORIES:Colloquium
ATTACH;FMTTYPE=image/png:https://cmsa.fas.harvard.edu/media/CMSA-Colloquium-5.5.2025.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20250506T161500
DTEND;TZID=America/New_York:20250506T181500
DTSTAMP:20260607T065147
CREATED:20250407T174129Z
LAST-MODIFIED:20250407T174129Z
UID:10003738-1746548100-1746555300@cmsa.fas.harvard.edu
SUMMARY:Geometry and Quantum Theory Seminar
DESCRIPTION:Geometry and Quantum Theory Seminar
URL:https://cmsa.fas.harvard.edu/event/quantumgeo_5625/
LOCATION:Science Center 507\, 1 Oxford Street\, Cambridge\, 02138
CATEGORIES:Geometry and Quantum Theory Seminar
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20250509T120000
DTEND;TZID=America/New_York:20250509T130000
DTSTAMP:20260607T065147
CREATED:20241211T195446Z
LAST-MODIFIED:20250506T153832Z
UID:10003649-1746792000-1746795600@cmsa.fas.harvard.edu
SUMMARY:Asset pricing with heterogeneous agents
DESCRIPTION:Member Seminar \nSpeaker: Sergiy Verstyuk\, Harvard CMSA \nTitle: Asset pricing with heterogeneous agents \nAbstract: This talk will introduce the basics of continuous-time finance\, discuss important existing theories and models\, as well as present some new asset pricing results in a setting with many heterogeneous investors. (Joint work with Puskar Mondal.) \n 
URL:https://cmsa.fas.harvard.edu/event/member-seminar-5925/
LOCATION:CMSA Room G10\, CMSA\, 20 Garden Street\, Cambridge\, MA\, 02138\, United States
CATEGORIES:Member Seminar
ATTACH;FMTTYPE=image/png:https://cmsa.fas.harvard.edu/media/CMSA-Member-Seminar-5.9.25.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20250512T150000
DTEND;TZID=America/New_York:20250512T160000
DTSTAMP:20260607T065147
CREATED:20250226T174007Z
LAST-MODIFIED:20250605T134144Z
UID:10003716-1747062000-1747065600@cmsa.fas.harvard.edu
SUMMARY:An index for 2d invertible phases of quantum many-body systems
DESCRIPTION:Quantum Field Theory and Physical Mathematics Seminar \nSpeaker: Nikita Sopenko\, IAS \nTitle: An index for 2d invertible phases of quantum many-body systems
URL:https://cmsa.fas.harvard.edu/event/qft_51225/
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-5.12.25-1.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20250512T163000
DTEND;TZID=America/New_York:20250512T173000
DTSTAMP:20260607T065147
CREATED:20250407T140851Z
LAST-MODIFIED:20250506T191033Z
UID:10003734-1747067400-1747071000@cmsa.fas.harvard.edu
SUMMARY:Factorizations for data analysis
DESCRIPTION:Colloquium \nSpeaker: Anna Seigal\, Harvard University \nTitle: Factorizations for data analysis \nAbstract: We can find structure in data by factoring it into building blocks\, which should be interpretable for the context at hand. A classical example is principal component analysis (PCA)\, which uses the eigendecomposition of the covariance matrix to find axes of variation in a dataset. Starting from PCA\, I will discuss matrix and tensor factorizations for data analysis\, and the linear and multilinear algebra that underpins their theoretical properties. We will see examples from causal inference\, independent component analysis\, and dimensionality reduction.
URL:https://cmsa.fas.harvard.edu/event/colloquium-51225/
LOCATION:CMSA Room G10\, CMSA\, 20 Garden Street\, Cambridge\, MA\, 02138\, United States
CATEGORIES:Colloquium
ATTACH;FMTTYPE=image/png:https://cmsa.fas.harvard.edu/media/CMSA-Colloquium-5.12.2025.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20250514T120000
DTEND;TZID=America/New_York:20250514T130000
DTSTAMP:20260607T065147
CREATED:20250501T182905Z
LAST-MODIFIED:20250502T173004Z
UID:10003746-1747224000-1747227600@cmsa.fas.harvard.edu
SUMMARY:Report on the Perimeter Institute Theory+AI Workshop
DESCRIPTION:Conference Reports  \nSpeaker: Hugo Cui\, Harvard CMSA \nTitle: Report on the Perimeter Institute Theory+AI Workshop \nAbstract: I will give a survey and brief summary of some of the talks given at the Theory+AI Workshop: Theoretical Physics for AI event organized by Perimeter Institute in April\, on approaches to machine learning theory inspired from physics. \nLink : https://events.perimeterinstitute.ca/event/993/
URL:https://cmsa.fas.harvard.edu/event/confrep_51425/
LOCATION:CMSA 20 Garden Street Cambridge\, Massachusetts 02138 United States
CATEGORIES:Conference Reports
ATTACH;FMTTYPE=image/png:https://cmsa.fas.harvard.edu/media/CMSA-Conference-Reports-5.14.2025.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20250516T120000
DTEND;TZID=America/New_York:20250516T130000
DTSTAMP:20260607T065147
CREATED:20250218T161047Z
LAST-MODIFIED:20250513T152517Z
UID:10003714-1747396800-1747400400@cmsa.fas.harvard.edu
SUMMARY:Echo Chamber: RL Post-training Amplifies Behaviors Learned in Pretraining
DESCRIPTION:Member Seminar \nSpeaker: Samy Jelassi\, CMSA \nTitle: Echo Chamber: RL Post-training Amplifies Behaviors Learned in Pretraining \nAbstract: Reinforcement Learning has become a crucial step in training state-of-the-art language models such as DeepSeek-R1 for solving mathematical problems. In this talk\, I will first review the mechanisms of Reinforcement Learning fine-tuning. Then\, I will present a systematic end-to-end study of RL fine-tuning for mathematical reasoning\, training models entirely from scratch on different mixtures of fully open datasets and fine-tuning them with RL. Doing so allows us to investigate the effects of the pretraining data mixture on the behavior of RL\, and its interaction with the model size and choices of the algorithm hyperparameters. Our study reveals that RL algorithms consistently converge towards a dominant output distribution\, amplifying patterns in the pretraining data. We also find that models of different scales trained on the same data mixture will converge to distinct output distributions\, suggesting that there are scale-dependent biases in model generalization. \nThe second part of the talk is based on a joint work with Rosie Zhao\, Alex Meterez\, Cengiz Pehlevan\, Sham Kakade and Eran Malach: https://arxiv.org/abs/2504.07912 \n 
URL:https://cmsa.fas.harvard.edu/event/member-seminar-51625/
LOCATION:CMSA Room G10\, CMSA\, 20 Garden Street\, Cambridge\, MA\, 02138\, United States
CATEGORIES:Member Seminar
ATTACH;FMTTYPE=image/png:https://cmsa.fas.harvard.edu/media/CMSA-Member-Seminar-5.16.25.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20250731T110000
DTEND;TZID=America/New_York:20250731T120000
DTSTAMP:20260607T065147
CREATED:20250730T163542Z
LAST-MODIFIED:20250730T182012Z
UID:10003759-1753959600-1753963200@cmsa.fas.harvard.edu
SUMMARY:Joint BHI/CMSA Foundation Seminar: The semiclassical energy outflux emerging from a collapsing shell
DESCRIPTION:Joint BHI/CMSA Foundation Seminar \nLocation: BHI seminar room \nSpeaker: Noa Zilberman (Princeton University) \nTitle: The semiclassical energy outflux emerging from a collapsing shell \nAbstract: When a compact object collapses to form a black hole\, quantum field theory predicts the emission of an energy outflux to future null infinity\, which later relaxes to Hawking radiation. Within the semiclassical framework\, we derive a simple\, closed form\, analytical expression for the energy outflux emitted from a spherical thin null shell collapsing to form a black hole. In particular\, this energy outflux vanishes (quadratically in r-2M) as the shell approaches the horizon. This result refutes claims that the Hawking energy outflux originates from the collapsing body\, showing instead that it develops in a broad strong-field region. Additionally\, this vanishing implies that semiclassical backreaction cannot prevent or significantly affect the classical process of gravitational collapse and horizon formation (as sometimes claimed). \n 
URL:https://cmsa.fas.harvard.edu/event/joint-bhi-cmsa-foundation-seminar-the-semiclassical-energy-outflux-emerging-from-a-collapsing-shell/
LOCATION:Black Hole Initiative\, 20 Garden Street\, Cambridge MA\, CMSA\, 20 Garden Street\, Cambridge\, MA\, 02138\, United States
CATEGORIES:Foundation Seminar
ATTACH;FMTTYPE=image/png:https://cmsa.fas.harvard.edu/media/CMSA-BHI-Joint-Foundations-Seminar-07.31.25-scaled.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20250902T161500
DTEND;TZID=America/New_York:20250902T183000
DTSTAMP:20260607T065147
CREATED:20250829T204330Z
LAST-MODIFIED:20250902T170240Z
UID:10003773-1756829700-1756837800@cmsa.fas.harvard.edu
SUMMARY:Fukaya category and gauge theory
DESCRIPTION:Geometry and Quantum Theory Seminar \nSpeaker: Saman Habibi Esfahani\, Harvard CMSA \nTitle: Fukaya category and gauge theory \nAbstract: After setting up some background\, I will discuss the Fukaya $A_\ infty$-category and several instances where it appears in gauge theory\, such as in the study of flat connections on Riemann surfaces\, holomorphic sections of some hyperkähler bundles\, and instantons and holomorphic curves in K3 surfaces. If time permits\, I will also outline potential applications of these ideas to the study of 3-manifolds and manifolds with special holonomy. \n  \n 
URL:https://cmsa.fas.harvard.edu/event/quantumgeo_9225/
LOCATION:Science Center 507\, 1 Oxford Street\, Cambridge\, 02138
CATEGORIES:Geometry and Quantum Theory Seminar
ATTACH;FMTTYPE=image/png:https://cmsa.fas.harvard.edu/media/CMSA-Geometry-Quantum-Theory-9.2.25.edit_-scaled.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20250909T161500
DTEND;TZID=America/New_York:20250909T183000
DTSTAMP:20260607T065147
CREATED:20250829T204407Z
LAST-MODIFIED:20250908T135742Z
UID:10003774-1757434500-1757442600@cmsa.fas.harvard.edu
SUMMARY:Higher categories of cobordisms
DESCRIPTION:Geometry and Quantum Theory Seminar \nSpeaker: Lorenzo Riva \nTitle: Higher categories of cobordisms \nAbstract: I will give a brief introduction to topological field theories from a higher categorical perspective. After saying a few things about higher categories\, I will define a family of n-categories of bordisms and talk about their universal properties. I will try to squeeze in the canonical example — representations of the 2-dimensional oriented bordism 2-category are separable symmetric Frobenius algebras — and\, time permitting\, talk about my current work. \n 
URL:https://cmsa.fas.harvard.edu/event/quantumgeo_9925/
LOCATION:Science Center 507\, 1 Oxford Street\, Cambridge\, 02138
CATEGORIES:Geometry and Quantum Theory Seminar
ATTACH;FMTTYPE=image/png:https://cmsa.fas.harvard.edu/media/CMSA-Geometry-Quantum-Theory-9.9.25-scaled.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20250915T150000
DTEND;TZID=America/New_York:20250915T160000
DTSTAMP:20260607T065147
CREATED:20250910T193835Z
LAST-MODIFIED:20250910T194841Z
UID:10003788-1757948400-1757952000@cmsa.fas.harvard.edu
SUMMARY:Orientifolds for F-theory on K3 Surfaces
DESCRIPTION:Quantum Field Theory and Physical Mathematics Seminar \nSpeaker: Chuck Doran (Alberta/CMSA) \nTitle: Orientifolds for F-theory on K3 Surfaces \nAbstract: Compactification of F-theory on an elliptically fibered K3 surface provides a framework to encode type IIB string theory on elliptic curves\, with the Kaehler modulus of the elliptic curve encoded in the complex structure of the elliptic fibers. In work with Malmendier\, Mendez-Diez\, and Rosenberg we extend that perspective by examining F-theory orientifolds on elliptically fibered K3 surfaces and connecting them to D-brane classifications using real K-theory (KR-theory).  The real structures—antiholomorphic involutions—on our K3 surfaces connect the geometry with the physics\, providing a natural setting for understanding the interplay between elliptic fibration structures and D-brane classifications in F-theory. We construct Real normal forms with their associated antiholomorphic involutions and use this to make explicit the 2-torsion Brauer twist that relates our normal forms to the Jacobian (Weierstrass normal form) elliptic fibration\, including the realization of a representative for the twisting class as an Azumaya algebra. This all connects back to the physics by considering three families of real K3 surfaces whose string limits give the three different type IIB theories on P1 with four type I_0^∗ Kodaira fibers.
URL:https://cmsa.fas.harvard.edu/event/qft_91525/
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-9.15.25-scaled.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20250915T163000
DTEND;TZID=America/New_York:20250915T173000
DTSTAMP:20260607T065147
CREATED:20250904T152315Z
LAST-MODIFIED:20250904T152759Z
UID:10003776-1757953800-1757957400@cmsa.fas.harvard.edu
SUMMARY:Topological Manifolds – The First 100 Years
DESCRIPTION:Colloquium \nSpeaker: Michael Freedman (Harvard CMSA and Logical Intelligence) \nTitle: Topological Manifolds – The First 100 Years \nAbstract: I’ll review manifold topology in the topological category from its start with work of Rado (1925) and Kneser (1926) to the present. Work of Moise\, Mazur\, Kirby\, Siebenmann\, Sullivan\, Kruskal\, and the speaker will be discussed. In my view there is one pressing open question (the A-B slice problem). I will end with some thoughts on putting an AI to work on it. \n  \n 
URL:https://cmsa.fas.harvard.edu/event/colloquium-91525/
LOCATION:CMSA Room G10\, CMSA\, 20 Garden Street\, Cambridge\, MA\, 02138\, United States
CATEGORIES:Colloquium
ATTACH;FMTTYPE=image/png:https://cmsa.fas.harvard.edu/media/CMSA-Colloquium-9.15.2025-scaled.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20250918T160000
DTEND;TZID=America/New_York:20250918T170000
DTSTAMP:20260607T065147
CREATED:20250904T162209Z
LAST-MODIFIED:20250910T174655Z
UID:10003777-1758211200-1758214800@cmsa.fas.harvard.edu
SUMMARY:Moduli spaces of 4d N=2 quantum field theories
DESCRIPTION:Differential Geometry and Physics Seminar  \nSpeaker: Robert Moscrop\, CMSA \nTitle: Moduli spaces of 4d N=2 quantum field theories \nAbstract: Supersymmetry endows quantum field theories with several rich algebraic and geometric structures associated to their moduli space of vacua\, providing powerful tools to study such theories non-perturbatively. For example\, in four-dimensional theories with eight supercharges\, the low energy dynamics of the theory is captured by an algebraic completely integrable system whose base is the Coulomb branch– a particular distinguished submanifold of the moduli space. This structure is so tightly constrained\, that there is an ongoing program to classify such theories purely by understanding their Coulomb branch geometry. In this talk\, I will give a gentle introduction to the geometry of the moduli spaces of 4d N=2 theories and\, time permitting\, discuss some recent results showcasing how the geometry of the Coulomb branch can be used to constrain certain physical quantities of the theory. \n  \n  \n 
URL:https://cmsa.fas.harvard.edu/event/dgphys_91825/
LOCATION:CMSA Room G10\, CMSA\, 20 Garden Street\, Cambridge\, MA\, 02138\, United States
CATEGORIES:Differential Geometry and Physics Seminar
ATTACH;FMTTYPE=image/png:https://cmsa.fas.harvard.edu/media/DG-Physics-Seminar-9.18.2025-scaled.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20250919T120000
DTEND;TZID=America/New_York:20250919T130000
DTSTAMP:20260607T065147
CREATED:20241211T195345Z
LAST-MODIFIED:20250918T184123Z
UID:10003648-1758283200-1758286800@cmsa.fas.harvard.edu
SUMMARY:Top-Down Perspectives on Symmetry Theories
DESCRIPTION:Member Seminar \nSpeaker: Max Hubner \nTitle: Top-Down Perspectives on Symmetry Theories \nAbstract: I will review the construction and utility of symmetry theories for string constructed quantum field theories. Symmetry theories are extra-dimensional auxiliary theories separating aspects of a quantum field theory’s symmetries from many of its more messy features. For QFTs with extra-dimensional string constructions the symmetry theory derives directly from the extra-dimensional geometry. This perspective allows for the study of symmetries of famously string engineered systems\, such as SCFTs in 5D and 6D\, which we will discuss on an example by example basis.
URL:https://cmsa.fas.harvard.edu/event/member-seminar-91925/
LOCATION:Common Room\, CMSA\, 20 Garden Street\, Cambridge\, MA\, 02138\, United States
CATEGORIES:Member Seminar
ATTACH;FMTTYPE=image/png:https://cmsa.fas.harvard.edu/media/CMSA-Member-Seminar-9.19.25-scaled.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20250922T150000
DTEND;TZID=America/New_York:20250922T160000
DTSTAMP:20260607T065147
CREATED:20250826T190916Z
LAST-MODIFIED:20250917T134457Z
UID:10003761-1758553200-1758556800@cmsa.fas.harvard.edu
SUMMARY:Non-Supersymmetric Orbifolds\, Quivers and Chen-Ruan Orbifold Cohomology
DESCRIPTION:Quantum Field Theory and Physical Mathematics Seminar \nSpeaker: Max Hübner (Uppsala & CMSA) \nTitle: Non-Supersymmetric Orbifolds\, Quivers and Chen-Ruan Orbifold Cohomology \nAbstract: We consider D3-brane probes of non-supersymmetric orbifolds and IIA on the same class of non-supersymmetric orbifolds. Both setups are characterized\, in part\, by quivers (which in the latter case relate for example to D0-brane probes) from which symmetries constraining the scale-dependence and tachyonic instabilities of the two systems\, respectively\, can be derived. We demonstrate that these considerations can be matched via a geometric analysis of the asymptotic boundary of the relevant orbifolds\, in all cases\, via considerations centered on Chen-Ruan orbifold cohomology.
URL:https://cmsa.fas.harvard.edu/event/qft_92225/
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-9.22.25.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20250922T163000
DTEND;TZID=America/New_York:20250922T173000
DTSTAMP:20260607T065147
CREATED:20250826T191126Z
LAST-MODIFIED:20250914T170550Z
UID:10003732-1758558600-1758562200@cmsa.fas.harvard.edu
SUMMARY:Turbulent Mixing and Antagonistic Microorganisms
DESCRIPTION:Colloquium \nSpeaker: David Nelson\, Harvard \nTitle: Turbulent Mixing and Antagonistic Microorganisms \nAbstract: Unlike coffee and cream that homogenize when stirred\, growing micro-organisms (e.g.\, bacteria and baker’s yeast) can actively kill each other and avoid mixing.  How do such antagonistic interactions impact the growth and survival of competing strains\, while being spatially advected by turbulent flows?  By using analytic arguments and numerical simulations of a continuum model\, we describe the dynamics of two antagonistic strains that are dispersed by both compressible and incompressible turbulent flows in two spatial dimensions.  A key parameter is the ratio of the fluid transport time to that of biological reproduction\, which determines the winning organism that ultimately takes over the whole population from an initial heterogeneous state\, a process known as fixation.  By quantifying the probability and mean time for fixation\, we discuss how turbulence raises the threshold for biological nucleation and antagonism suppresses flow-induced mixing by depleting the population at interfaces. We highlight the unusual biological consequences of the interplay of turbulent fluid flows with antagonistic population dynamics\, with potential implications for marine microbial ecology and origins of biological chirality.
URL:https://cmsa.fas.harvard.edu/event/colloquium_92225/
LOCATION:CMSA Room G10\, CMSA\, 20 Garden Street\, Cambridge\, MA\, 02138\, United States
CATEGORIES:Colloquium
ATTACH;FMTTYPE=image/png:https://cmsa.fas.harvard.edu/media/CMSA-Colloquium-9.22.2025-scaled.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20250925T160000
DTEND;TZID=America/New_York:20250925T170000
DTSTAMP:20260607T065147
CREATED:20250826T192430Z
LAST-MODIFIED:20250919T142937Z
UID:10003762-1758816000-1758819600@cmsa.fas.harvard.edu
SUMMARY:Degeneration of Calabi-Yau 3-folds and 3-forms
DESCRIPTION:Differential Geometry and Physics Seminar  \nSpeaker: Teng Fei\, Rutgers \nTitle: Degeneration of Calabi-Yau 3-folds and 3-forms \nAbstract: We study the geometries associated to various 3-forms on a symplectic 6-manifold of different orbital types. As an application\, we demonstrate how this can be used to find Lagrangian foliations and other geometric structures of interest arising from certain degeneration of Calabi-Yau 3-folds. \n 
URL:https://cmsa.fas.harvard.edu/event/dgphys_92525/
LOCATION:CMSA Room G10\, CMSA\, 20 Garden Street\, Cambridge\, MA\, 02138\, United States
CATEGORIES:Differential Geometry and Physics Seminar
ATTACH;FMTTYPE=image/png:https://cmsa.fas.harvard.edu/media/DG-Physics-Seminar-9.25.2025.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20250926T120000
DTEND;TZID=America/New_York:20250926T130000
DTSTAMP:20260607T065147
CREATED:20250826T193028Z
LAST-MODIFIED:20250918T172135Z
UID:10003763-1758888000-1758891600@cmsa.fas.harvard.edu
SUMMARY:Sections of fibrations onto curves in characteristic p>0
DESCRIPTION:Member Seminar \nSpeaker: Iacopo Brivio \nTitle: Sections of fibrations onto curves in characteristic p>0 \nAbstract: This talk is based on joint work in progress with Ben Church. Using symplectic geometry\, Pieloch showed that every smooth fibration $f\colon X\to \mathbb{P}^1$ of complex projective varieties always admits a section. I will explain how this theorem can be recovered using techniques from Hodge theory and the Minimal Model Program. An advantage of this approach is that it allows for a positive characteristic generalization\, by replacing the Hodge theoretic input by a crystalline one. I will also give an example showing that Pieloch’s result can fail in characteristic p>0.
URL:https://cmsa.fas.harvard.edu/event/member-seminar-92625/
LOCATION:Common Room\, CMSA\, 20 Garden Street\, Cambridge\, MA\, 02138\, United States
CATEGORIES:Member Seminar
ATTACH;FMTTYPE=image/png:https://cmsa.fas.harvard.edu/media/CMSA-Member-Seminar-9.26.25-1.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20250929T150000
DTEND;TZID=America/New_York:20250929T160000
DTSTAMP:20260607T065147
CREATED:20250924T181258Z
LAST-MODIFIED:20250924T183325Z
UID:10003795-1759158000-1759161600@cmsa.fas.harvard.edu
SUMMARY:Graph integrals on Kahler manifolds
DESCRIPTION:Quantum Field Theory and Physical Mathematics Seminar \nSpeaker: Minghao Wang\, Boston University \nTitle: Graph integrals on Kahler manifolds \nAbstract: I will talk about my recent work with Junrong Yan. We proved the convergence of Graph integrals on analytic Kahler manifolds in the sense of Cauchy principal values\, which are originally from holomorphic quantum field theories. In particular\, this allows us to construct geometric invariants of Calabi-Yau metrics. I will also talk about some potential applications of our results. References: arXiv:2507.09170\, arXiv:2401.08113
URL:https://cmsa.fas.harvard.edu/event/qft_92925/
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-9.29.25-scaled.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20250930T161500
DTEND;TZID=America/New_York:20250930T183000
DTSTAMP:20260607T065147
CREATED:20250829T204925Z
LAST-MODIFIED:20250929T175811Z
UID:10003775-1759248900-1759257000@cmsa.fas.harvard.edu
SUMMARY:Geometry and Quantum Theory Seminar
DESCRIPTION:Geometry and Quantum Theory Seminar \nSpeaker 1: Max Hubner\, CMSA \nTitle: On Topological Structures in String Theory \nAbstract: Geometric engineering constructions in string theory often realize QFTs relative to an extra-dimensional geometry. This perspective parallels the symmetry TFT construction where a QFT is presented relative to its extra-dimensional symmetry quiche. Unsurprisingly\, as we will discuss\, these constructions are related. Topological features of the extra-dimensional geometry map onto the symmetry TFT. We discuss examples and generalization beyond purely geometric constructions in string theory. \nSpeaker 2: Bowen Yang\, CMSA \nTitle: Bounded L theory \nAbstract: Bounded L-groups arise in the intersection of algebraic L-theory and large-scale geometry\, providing a framework for quadratic forms and automorphisms subject to uniform control conditions. These groups play a role in topology and surgery theory\, especially in contexts where one needs to measure obstructions not just algebraically but also geometrically\, with bounds on propagation or support. In this talk I will give a gentle introduction to the basic definitions\, explain how bounded L-groups differ from classical L-groups\, and outline an application to quantum many body invariants.
URL:https://cmsa.fas.harvard.edu/event/quantumgeo_93025/
LOCATION:Science Center 507\, 1 Oxford Street\, Cambridge\, 02138
CATEGORIES:Geometry and Quantum Theory Seminar
ATTACH;FMTTYPE=image/png:https://cmsa.fas.harvard.edu/media/CMSA-Geometry-Quantum-Theory-9.30.25.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20251001T140000
DTEND;TZID=America/New_York:20251001T150000
DTSTAMP:20260607T065147
CREATED:20250128T214901Z
LAST-MODIFIED:20251002T140605Z
UID:10003710-1759327200-1759330800@cmsa.fas.harvard.edu
SUMMARY:Tropicalized quantum field theory
DESCRIPTION:New Technologies in Mathematics Seminar \nSpeaker: Michael Borinsky\, Perimeter Institute  \nTitle: Tropicalized quantum field theory \nAbstract: Quantum field theory (QFT) is one of the most accurate methods for making phenomenological predictions in physics\, but it has a significant drawback: obtaining concrete predictions from it is computationally very demanding. The standard perturbative approach expands an interacting QFT around a free QFT\, using Feynman diagrams. However\, the number of these diagrams grows superexponentially\, making the approach quickly infeasible. \nI will talk about arXiv:2508.14263\, which introduces an intermediate layer between free and interacting field theories: a tropicalized QFT. Often\, this tropicalized QFT can be solved exactly. The exact solution manifests as a non-linear recursion equation fulfilled by the expansion coefficients of the quantum effective action. Geometrically\, this recursion computes volumes of moduli spaces of metric graphs and is thereby analogous to Mirzakhani’s volume recursions on the moduli space of curves. Building on this exact solution\, an algorithm can be constructed that samples points from the moduli space of graphs approximately proportional to their perturbative contribution. Via a standard Monte Carlo approach we can evaluate the original QFT using this algorithm. Remarkably\, this algorithm requires only polynomial time and memory\, suggesting that perturbative quantum field theory computations actually lie in the polynomial-time complexity class\, while all known algorithms for evaluating individual Feynman integrals are at least exponential in time and memory. The (potential) capabilities of this approach are remarkable: For instance\, we can compute perturbative expansions of massive scalar D=3 phi^3 and D=4 phi^4 quantum field theories up to loop orders between 20 and 50 using a basic proof-of-concept implementation. These perturbative orders are completely inaccessible using a naive approach.
URL:https://cmsa.fas.harvard.edu/event/newtech_10125/
LOCATION:Virtual
CATEGORIES:New Technologies in Mathematics Seminar
ATTACH;FMTTYPE=image/png:https://cmsa.fas.harvard.edu/media/CMSA-NTM-Seminar-10.1.2025.docx-1-scaled.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20251002T160000
DTEND;TZID=America/New_York:20251002T170000
DTSTAMP:20260607T065147
CREATED:20250904T162108Z
LAST-MODIFIED:20250926T180606Z
UID:10003778-1759420800-1759424400@cmsa.fas.harvard.edu
SUMMARY:Special Kähler geometry and collapsing
DESCRIPTION:Differential Geometry and Physics Seminar  \nSpeaker: Valentino Tosatti\, NYU Courant Institute \nTitle: Special Kähler geometry and collapsing \nAbstract: Special Kähler geometry was first discovered in the context of N=2 supersymmetric 4D gauge theories\, and it also plays a prominent role in mirror symmetry. A key observation of Donagi-Witten and Freed is that the base of every algebraic integrable system admits a special Kähler metric\, while the total space admits a hyperkähler metric. In this talk I will consider compact hyperkähler manifolds with a an algebraic integrable system (i.e. a holomorphic Lagrangian torus fibration)\, and consider a family of hyperkähler metrics such that the volume of the torus fibers shrinks to zero. I will explain how the hyperkähler metrics must collapse to a special Kähler metric on the base (away from the discriminant locus)\, and what we can say about the metric completion of the limit. \n 
URL:https://cmsa.fas.harvard.edu/event/dgphys_10225/
LOCATION:CMSA Room G10\, CMSA\, 20 Garden Street\, Cambridge\, MA\, 02138\, United States
CATEGORIES:Differential Geometry and Physics Seminar
ATTACH;FMTTYPE=image/png:https://cmsa.fas.harvard.edu/media/DG-Physics-Seminar-10.2.2025.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20251003T120000
DTEND;TZID=America/New_York:20251003T130000
DTSTAMP:20260607T065147
CREATED:20250827T140756Z
LAST-MODIFIED:20250918T171806Z
UID:10003764-1759492800-1759496400@cmsa.fas.harvard.edu
SUMMARY:Local Donaldson-Scaduto conjecture
DESCRIPTION:Member Seminar \nSpeaker: Saman Habibi Esfahani \nTitle: Local Donaldson-Scaduto conjecture \nAbstract: This talk is based on joint works with Gora Bera and Yang Li. Motivated by collapsing Calabi-Yau 3-folds and G2-manifolds with Lefschetz K3 fibrations in the adiabatic setting\, Donaldson and Scaduto conjectured the existence and uniqueness of a special Lagrangian pair-of-pants in the Calabi-Yau 3-fold $ X \times \mathbb{C}$\, where $X$ is either a hyperkähler K3 surface (global version) or an A2-type ALE hyperkähler 4-manifold (local version). After a brief introduction to the subject\, we discuss the significance of this conjecture in the study of Calabi-Yau 3-folds and G2-manifolds\, and then prove the local version of the conjecture. \n 
URL:https://cmsa.fas.harvard.edu/event/member-seminar-10325/
LOCATION:Common Room\, CMSA\, 20 Garden Street\, Cambridge\, MA\, 02138\, United States
CATEGORIES:Member Seminar
ATTACH;FMTTYPE=image/png:https://cmsa.fas.harvard.edu/media/CMSA-Member-Seminar-10.3.25.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20251006T150000
DTEND;TZID=America/New_York:20251006T160000
DTSTAMP:20260607T065147
CREATED:20250924T182709Z
LAST-MODIFIED:20251006T144221Z
UID:10003796-1759762800-1759766400@cmsa.fas.harvard.edu
SUMMARY:Non-perturbative aspects of self-dual gauge theory
DESCRIPTION:Quantum Field Theory and Physical Mathematics Seminar \nSpeaker: Kevin Costello (Perimeter Institute)\n\nTitle: Non-perturbative aspects of self-dual gauge theory\n\nAbstract: Self-dual gauge theory is conformal in perturbation theory\, but has a non-trivial beta-function when instanton effects are included. I will give two computations of this beta-function\, one based on the Grothendieck-Riemann-Roch formula and one using holography in the topological string.   This leads to two new ways to compute the standard QCD beta-function at one loop\, without using Feynman diagrams.  If time permits\, I will also discuss how instantons effect scattering amplitudes.\n\n 
URL:https://cmsa.fas.harvard.edu/event/qft_100625/
LOCATION:Virtual
CATEGORIES:Quantum Field Theory and Physical Mathematics
ATTACH;FMTTYPE=image/png:https://cmsa.fas.harvard.edu/media/CMSA-QFT-and-Physical-Mathematics-10.6.25-scaled.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20251006T163000
DTEND;TZID=America/New_York:20251006T173000
DTSTAMP:20260607T065147
CREATED:20250914T165359Z
LAST-MODIFIED:20250914T165941Z
UID:10003794-1759768200-1759771800@cmsa.fas.harvard.edu
SUMMARY:Geometry of dimer models
DESCRIPTION:Colloquium \nSpeaker: Alexei Borodin\, MIT \nTitle: Geometry of dimer models \nAbstract: Random dimer coverings of large planar graphs are known to exhibit unusual and visually apparent asymptotic phenomena that include formation of frozen regions and various phases in the unfrozen ones. For a specific family of subgraphs of the (periodically weighted) square lattice known as the Aztec diamonds\, the asymptotic behavior of dimers admits a precise description in terms of geometry of underlying Riemann surfaces. The goal of the talk is to explain how the surface structure manifests itself through the statistics of dimers. Based on joint works with T. Berggren and M. Duits. \n 
URL:https://cmsa.fas.harvard.edu/event/colloquium_10625/
LOCATION:CMSA Room G10\, CMSA\, 20 Garden Street\, Cambridge\, MA\, 02138\, United States
CATEGORIES:Colloquium
ATTACH;FMTTYPE=image/png:https://cmsa.fas.harvard.edu/media/CMSA-Colloquium-10.6.2025.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20251007T161500
DTEND;TZID=America/New_York:20251007T183000
DTSTAMP:20260607T065147
CREATED:20251001T183038Z
LAST-MODIFIED:20251007T132737Z
UID:10003802-1759853700-1759861800@cmsa.fas.harvard.edu
SUMMARY:A Classifying Space for Phases of Matrix Product States
DESCRIPTION:Geometry and Quantum Theory Seminar \nSpeakers: Daniel Spiegel\, Harvard Math \nTitle: A Classifying Space for Phases of Matrix Product States \nAbstract: Alexei Kitaev has conjectured that there should be a loop spectrum consisting of spaces of gapped invertible quantum spin systems\, indexed by spatial dimension d of the lattice. Motivated by Kitaev’s conjecture\, I will detail a concrete construction of a topological space B consisting of translation invariant injective matrix product states (MPS) of all physical and bond dimensions\, which plays the role Kitaev’s space in dimension d = 1. Having such a space is a useful tool in the discussion of parametrized phases of MPS; in fact it allows us to define a parametrized phase as a homotopy class of maps into B. The space B is constructed as the quotient of a contractible space E of MPS tensors modulo gauge transformations. The projection map from E to B is a quasifibration\, from which we can compute the homotopy groups of the classifying space B by a long exact sequence. In particular\, B has the weak homotopy type K(Z\, 2) x K(Z\, 3)\, shedding light on Kitaev’s conjecture in the context of MPS. \nDaniel Spiegel will speak for 60 minutes. \nSunghyuk Park  (CMSA) will also speak for 15 minutes
URL:https://cmsa.fas.harvard.edu/event/quantumgeo_10725/
LOCATION:Science Center 507\, 1 Oxford Street\, Cambridge\, 02138
CATEGORIES:Geometry and Quantum Theory Seminar
ATTACH;FMTTYPE=image/png:https://cmsa.fas.harvard.edu/media/CMSA-Geometry-Quantum-Theory-10.7.25-scaled.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20251008T140000
DTEND;TZID=America/New_York:20251008T150000
DTSTAMP:20260607T065147
CREATED:20250930T181425Z
LAST-MODIFIED:20251009T195959Z
UID:10003801-1759932000-1759935600@cmsa.fas.harvard.edu
SUMMARY:Understanding Optimization in Deep Learning with Central Flows
DESCRIPTION:New Technologies in Mathematics Seminar \nSpeaker: Alex Damian\, Harvard \nTitle: Understanding Optimization in Deep Learning with Central Flows \nAbstract: Traditional theories of optimization cannot describe the dynamics of optimization in deep learning\, even in the simple setting of deterministic training. The challenge is that optimizers typically operate in a complex\, oscillatory regime called the “edge of stability.” In this paper\, we develop theory that can describe the dynamics of optimization in this regime. Our key insight is that while the *exact* trajectory of an oscillatory optimizer may be challenging to analyze\, the *time-averaged* (i.e. smoothed) trajectory is often much more tractable. To analyze an optimizer\, we derive a differential equation called a “central flow” that characterizes this time-averaged trajectory. We empirically show that these central flows can predict long-term optimization trajectories for generic neural networks with a high degree of numerical accuracy. By interpreting these central flows\, we are able to understand how gradient descent makes progress even as the loss sometimes goes up; how adaptive optimizers “adapt” to the local loss landscape; and how adaptive optimizers implicitly navigate towards regions where they can take larger steps. Our results suggest that central flows can be a valuable theoretical tool for reasoning about optimization in deep learning. \n 
URL:https://cmsa.fas.harvard.edu/event/newtech_10825/
LOCATION:Hybrid – G10
CATEGORIES:New Technologies in Mathematics Seminar
ATTACH;FMTTYPE=image/png:https://cmsa.fas.harvard.edu/media/CMSA-NTM-Seminar-10.8.2025-scaled.png
END:VEVENT
END:VCALENDAR