BEGIN:VCALENDAR VERSION:2.0 PRODID:-//CMSA - ECPv6.16.3//NONSGML v1.0//EN CALSCALE:GREGORIAN METHOD:PUBLISH X-WR-CALNAME:CMSA X-ORIGINAL-URL:https://cmsa.fas.harvard.edu X-WR-CALDESC:Events for CMSA REFRESH-INTERVAL;VALUE=DURATION:PT1H X-Robots-Tag:noindex X-PUBLISHED-TTL:PT1H BEGIN:VTIMEZONE TZID:America/New_York BEGIN:DAYLIGHT TZOFFSETFROM:-0500 TZOFFSETTO:-0400 TZNAME:EDT DTSTART:20240310T070000 END:DAYLIGHT BEGIN:STANDARD TZOFFSETFROM:-0400 TZOFFSETTO:-0500 TZNAME:EST DTSTART:20241103T060000 END:STANDARD BEGIN:DAYLIGHT TZOFFSETFROM:-0500 TZOFFSETTO:-0400 TZNAME:EDT DTSTART:20250309T070000 END:DAYLIGHT BEGIN:STANDARD TZOFFSETFROM:-0400 TZOFFSETTO:-0500 TZNAME:EST DTSTART:20251102T060000 END:STANDARD BEGIN:DAYLIGHT TZOFFSETFROM:-0500 TZOFFSETTO:-0400 TZNAME:EDT DTSTART:20260308T070000 END:DAYLIGHT BEGIN:STANDARD TZOFFSETFROM:-0400 TZOFFSETTO:-0500 TZNAME:EST DTSTART:20261101T060000 END:STANDARD END:VTIMEZONE BEGIN:VEVENT DTSTART;TZID=America/New_York:20251204T120000 DTEND;TZID=America/New_York:20251204T130000 DTSTAMP:20260702T074049 CREATED:20250904T163130Z LAST-MODIFIED:20251203T150446Z UID:10003786-1764849600-1764853200@cmsa.fas.harvard.edu SUMMARY:Towards a Dolbeault AGT correspondence DESCRIPTION:Differential Geometry and Physics Seminar \nSpeaker: Surya Raghavendran\, Yale \nTitle: Towards a Dolbeault AGT correspondence \nAbstract: The AGT correspondence and its extensions propose geometric constructions of vertex algebras and their modules from the cohomology of various moduli spaces of sheaves on surfaces. Physically\, the correspondence is illuminated throgh the holomorphic–topological twist of the six-dimensional N=(2\,0) superconformal field theories. In this talk\, I will describe a variant of AGT arising instead from the so-called minimal twist of these theories. In this setting\, the natural algebraic structures are holomorphic factorization algebras in three complex dimensions. From these\, one can extract an associative algebra together with a natural module\, which we conjecture to coincide with a quantization of the moduli of Higgs sheaves on surfaces. In examples\, this pair is furthermore expected to admit a Hodge–de Rham deformation to the Heisenberg algebra and its action on the cohomology of Hilbert schemes of surfaces\, as constructed by Grojnowski and Nakajima. \n  \n  \n  URL:https://cmsa.fas.harvard.edu/event/dgphys_12425/ 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-12.4.2025.docx-1-scaled.png END:VEVENT BEGIN:VEVENT DTSTART;TZID=America/New_York:20251201T163000 DTEND;TZID=America/New_York:20251201T173000 DTSTAMP:20260702T074049 CREATED:20251007T152747Z LAST-MODIFIED:20251201T144411Z UID:10003807-1764606600-1764610200@cmsa.fas.harvard.edu SUMMARY:Asymptotic Theory of Attention: In-Context Learning and Sparse Token Detection DESCRIPTION:Colloquium \nSpeaker: Yue M. Lu\, Harvard University \nTitle: Asymptotic Theory of Attention: In-Context Learning and Sparse Token Detection \nAbstract: Attention-based architectures exhibit striking emergent abilities—from learning tasks directly from context to detecting rare\, weak features in long sequences—yet a rigorous theory explaining these behaviors remains limited. In this talk\, I will present two recent exactly solvable models that develop a high-dimensional asymptotic theory of attention. \n(i) In-context learning. For linear attention pretrained on linear regression tasks\, we derive sharp asymptotics in a regime where token dimension\, context length\, and task diversity all scale proportionally\, while the number of pretraining examples scales quadratically. The resulting learning curve exhibits double descent and a phase transition separating a low-diversity memorization regime from a high-diversity regime of genuine in-context generalization. These predictions closely track empirical behavior in both linear-attention models and nonlinear Transformer architectures. \n(ii) Sparse-token classification. For detecting weak signals embedded in a small\, randomly located subset of tokens\, we analyze a single-layer attention classifier and determine its representational and learnability thresholds. Attention succeeds with only logarithmic signal scaling in the sequence length L\, outperforming linear baselines that require √L scaling. In a proportional high-dimensional regime\, we prove that two gradient descent steps yield nontrivial alignment between the query vector and the hidden signal\, leading to signal-adaptive attention. Exact formulas for the test error\, training loss\, and separability capacity quantify this advantage. URL:https://cmsa.fas.harvard.edu/event/colloquium-12125/ 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-12.1.2025-scaled.png END:VEVENT BEGIN:VEVENT DTSTART;TZID=America/New_York:20251124T163000 DTEND;TZID=America/New_York:20251124T173000 DTSTAMP:20260702T074049 CREATED:20251119T163856Z LAST-MODIFIED:20251119T184001Z UID:10003834-1764001800-1764005400@cmsa.fas.harvard.edu SUMMARY:Geometric Simplicity in Quantum Field Theory and Gravity DESCRIPTION:Colloquium \nSpeaker: Thomas Grimm\, Utrecht University \nTitle: Geometric Simplicity in Quantum Field Theory and Gravity \nAbstract: In physics we attribute much value to the emergence of simplicity\, both conceptually and for computations. Familiar examples include algebraic relations among Feynman amplitudes\, the surprising descriptions arising in large-N or duality limits\, and the central role played by symmetries. In this colloquium we discuss how tame geometry allows one to quantitatively describe such simplifications by introducing a measure of complexity. This framework relies on finiteness: the information content of the functions and domains required to specify a theory\, or an observable is finite. A key strength of the proposal is its generality as it applies to any physical quantity and can therefore be used both to analyze complexities within an individual Quantum Field Theory and to study the entire space of such theories. We present several applications and explain how this perspective ties in with our understanding of the expected properties of effective theories that can be coupled to Quantum Gravity. URL:https://cmsa.fas.harvard.edu/event/colloquium-112425/ 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-11.24.2025.docx-scaled.png END:VEVENT BEGIN:VEVENT DTSTART;TZID=America/New_York:20251120T140000 DTEND;TZID=America/New_York:20251120T150000 DTSTAMP:20260702T074049 CREATED:20251009T132440Z LAST-MODIFIED:20251009T132850Z UID:10003809-1763647200-1763650800@cmsa.fas.harvard.edu SUMMARY:Differentials and Singularities DESCRIPTION:Algebra Seminar \nSpeaker: Dawei Chen\, Boston College \nTitle: Differentials and Singularities \nAbstract: Given a holomorphic differential on a smooth algebraic curve\, we associate to it a Gorenstein curve singularity with Gm-action.  Conversely\, we show that every isolated Gorenstein curve singularity with Gm-action appears in this way.  This construction reveals a fascinating relation between differentials and singularities\, where the zero orders of the differentials determine the combinatorial data of the singularities.  In this talk\, I’ll provide many concrete examples of such singularities\, and explain how the study of deformations of these singularities can help us better understand the geometry of moduli spaces of differentials.  This is based on joint work with Fei Yu (Zhejiang University). \n  URL:https://cmsa.fas.harvard.edu/event/algebra-seminar_112025/ LOCATION:CMSA Room G10\, CMSA\, 20 Garden Street\, Cambridge\, MA\, 02138\, United States CATEGORIES:Algebra Seminar ATTACH;FMTTYPE=image/png:https://cmsa.fas.harvard.edu/media/CMSA-Algebra-Seminar-11.19.25-scaled.png END:VEVENT BEGIN:VEVENT DTSTART;TZID=America/New_York:20251117T163000 DTEND;TZID=America/New_York:20251117T173000 DTSTAMP:20260702T074049 CREATED:20250925T180503Z LAST-MODIFIED:20251106T161641Z UID:10003799-1763397000-1763400600@cmsa.fas.harvard.edu SUMMARY:Interaction of Statistics and Geometry: A New Landscape for Data Science DESCRIPTION:Colloquium \nSpeaker: Zhigang Yao (National University of Singapore) \nTitle: Interaction of Statistics and Geometry: A New Landscape for Data Science \nAbstract:  Classical statistics views data as real numbers or vectors in Euclidean space\, but modern challenges increasingly involve data with intrinsic geometric structures. A central problem in this direction is manifold fitting\, with origins in H. Whitney’s work of the 1930s. The Geometric Whitney Problems ask: given a set\, when can we construct a smooth 𝑑-dimensional manifold that approximates it\, and how accurately can we estimate it? \nIn this talk\, I will discuss recent progress on manifold fitting and its role in bridging geometry and data science. While many existing methods rely on restrictive assumptions\, the manifold hypothesis—that data often lie near non-Euclidean structures—remains fundamental in modern statistical learning. I will highlight both theoretical insights and algorithmic challenges\, drawing on recent works with\, as well as ongoing research. URL:https://cmsa.fas.harvard.edu/event/colloquium_111725/ 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-11.17.2025-scaled.png END:VEVENT BEGIN:VEVENT DTSTART;TZID=America/New_York:20251112T090000 DTEND;TZID=America/New_York:20251114T170000 DTSTAMP:20260702T074049 CREATED:20250502T181545Z LAST-MODIFIED:20251113T214753Z UID:10003745-1762938000-1763139600@cmsa.fas.harvard.edu SUMMARY:Geometry Meets Physics: Finiteness\, Tameness\, and Complexity DESCRIPTION:Geometry Meets Physics: Finiteness\, Tameness\, and Complexity \nDates: November 12–14\, 2025 \nLocation: CMSA G10\, 20 Garden Street\, Cambridge MA 02138 \n(note: this event is in-person only) \nFiniteness is a fundamental property in consistent physical theories. From the earliest days of quantum field theory and string theory\, the drive to eliminate unphysical infinities has been a guiding principle. More recently\, finiteness has emerged as a key criterion for constraining effective theories that can be embedded in quantum gravity.  Formulating and testing these constraints remains a central challenge in current research. \nIn parallel\, mathematics has made remarkable advanced in addressing finiteness questions using tame geometry. Built on the framework of o-minimal structures\, tame geometry offers a precise language for describing objects of finite geometric complexity. Recent developments\, such as sharp o-minimality\, go further by introducing a quantitative notion of complexity\, opening new directions for analyzing finiteness in mathematics and physics alike. \nThis workshop brings together mathematicians and physicists to exchange ideas\, explore new perspectives\, and spark collaborations at the interface of geometry\, logic\, and fundamental physics. \nInvited Speakers \n\nVijay Balasubramanian (UPenn)\nGregorio Baldi (CNRS\, IMJ-PRG & IAS)\nGal Binyamini (Weizmann Institute & IAS)\nRaf Cluckers (Lille\, France)\nMatilda Delgado (Max Planck Institute Munich)\nBruno Klingler (Humboldt University\, Berlin & IAS)\nAdele Padgett (Vienna)\nDavid Prieto (Utrecht)\nWashington Taylor (MIT)\nDavid Urbanik (IHES\, France & IAS)\nCumrun Vafa (Harvard)\nMick van Vliet (Utrecht)\nBenny Zak (Weizmann Institute & IAS)\n\nOrganizers: Thomas Grimm\, Harvard CMSA & Utrecht University | Gal Binyamini\, Weizmann Institute & IAS | Bruno Klingler\, Humboldt University\, Berlin & IAS \n  \nSchedule \n(download pdf) \nWednesday Nov. 12\, 2025 \n8:30–8:55 am\nMorning refreshments (Common Room) \n8:55–9:00 am\nIntroductions \n9:00–10:30 am\nLecture\nSpeaker: Gal Binyamini\, Weizmann Institute & IAS\nTitle: O-minimality: finiteness and complexity\nAbstract: O-minimality is a mathematical formalism of “tame geometry”: a geometry where every set has finite geometric complexity. I will give an introduction to o-minimality in general\, and to quantitative variants where one measures the complexity of sets in terms of some natural parameters. I’ll try to focus on the main examples that potentially come up in the interaction with physics\, and describe the state of the art and some conjectures. \n10:30–11:00 am\nBreak \n11:00 am–12:00 pm\nSpeaker: Benny Zak\, Weizmann Institute & IAS\nTitle: Analytic tameness – complex cells\nAbstract: Complex cells are a complex anayltic version of cells from o-minimality\, invented by Binyamini and Novikov. We aim to introduce complex cells\, and demonstrate their usefullness in quantifying the analytic information present in a complex set. If time permits\, we will discuss applications of this theory. \n12:00–1:00 pm\nCatered Lunch (Common Room) \n1:00–2:30 pm\nLecture\nSpeakers: David Prieto and Mick van Vliet\, Utrecht\nTitle: Tameness and Complexity in Physical Theories\nAbstract: We give an introductory overview of recent applications of o-minimality to physics\, focusing on quantum field theories and quantum gravity. In the first part of the lecture we explain how o-minimality makes a first appearance in physical theories when considering amplitudes in quantum field theory. In the second part\, we concentrate on a class of theories where finiteness principles seem to be essential\, namely the quantum field theories which are consistent with quantum gravity. We review some of these finiteness principles and interpret them through the lens of the o-minimal framework. Along the way\, we highlight recent progress in this direction\, as well as open questions to explore in the future. \n2:30–3:00 pm\nBreak with refreshments (Common Room) \n3:00–4:00 pm\nSpeaker: Matilda Delgado\, Max Planck Institute Munich\nTitle: Dualities and the Compactifiability of Moduli Space\nAbstract:  After introducing (self-)dualities in string theory and their action on the field content & spectrum of the theory\, I will present the notion of compactifiability for the moduli space of massless fields as the condition that its volume is finite or grows no faster than Euclidean space. I will argue that compactifiability generically implies the existence of non-trivial dualities by providing evidence from string theory. Moreover\, I will explain how one can connect compactifiability to the condition that the spectrum of objects charged under the duality group transform in a semisimple representation. Finally\, I will provide a bottom-up argument for compactifiability\, and argue that it (at least in supersymmetric cases) can be explained by the finiteness of the number of massless states upon compactification to 1D. Based on arXiv:2412.03640. \n5:00 PM\nMillennium Lecture and Reception: Pierre Deligne (IAS) (Science Center Hall D)\nTitle: What is the Hodge conjecture? \n  \nThursday\, Nov. 13\, 2025 \n8:30–9:00 am\nMorning refreshments (Common Room) \n9:00–10:30 am\nLecture\nSpeaker: Bruno Klingler\, Humboldt University\, Berlin & IAS\nTitle: Tame geometry and Hodge theory\nAbstract: I will give an introduction to applications of o-minimality in complex geometry\, in particular in Hodge theory. \n10:30–11:00 am\nBreak \n11:00 am–12:00 pm\nSpeaker: Cumrun Vafa\, Harvard\nTitle: The Swampland Program \n12:00–1:30 pm\nCatered Lunch (Common Room) \n1:30–2:30 pm\nSpeaker: Gregorio Baldi\, CNRS\, IMJ-PRG & IAS\nTitle: The Hodge locus\nAbstract: We will survey various recent results around the distribution of the Hodge locus of a (mixed) variation of Hodge structures. Various concrete applications to moduli spaces will also be presented. \n2:30–3:00 pm\nBreak with refreshments (Common Room) \n3:00–4:00 pm\nSpeaker: Vijay Balasubramanian\, U Penn\nTitle: Chaos and complexity in quantum dynamics \n4:30–5:30\nDiscussion/Q&A session \n6:30 PM\nDinner: Changsho Restaurant\, 1712 Massachusetts Ave.\, Cambridge\, MA 02138 \n  \nFriday Nov. 14\, 2025 \n8:30–9:00 am\nMorning refreshments (Common Room) \n9:00–10:00 am\nSpeaker: Washington Taylor\, MIT\nTitle: Finiteness\, connectivity\, and the power of fibrations in the Calabi-Yau landscape \n10:00–10:30am\nBreak \n10:30–11:30 am\nSpeaker: Adele Padgett\, Vienna\nTitle: Tameness of multisummable series\nAbstract: There are sophisticated theories of summability that map divergent series solutions of differential or functional equations to solutions that are holomorphic in sector-like domains. Van den Dries and Speissegger proved that functions obtained from real multisummable power series have tame geometric behavior when restricted to the real numbers. It would be desirable to know that these functions are also tame on their whole sector-like domains\, but recently Speissegger and I proved that these functions are in general only tame on part of their domains. I will present this result and discuss the domains on which some examples are tame\, including the Stirling series which appears in the asymptotic expansion of the Gamma function. In this talk\, “tame” means definable in an o-minimal structure. \n11:30 am–1:00 pm\nCatered Lunch (Common Room) \n1:00–2:00 pm\nSpeaker: Raf Cluckers\, Lille\, France\nTitle:  Finiteness and tameness in (non-archimedean) geometry\nAbstract: Non-archimedean geometry work with orders of magnitude rather than with precise measurements. The former works for example with orders of vanishing of functions\, and the latter typically works with real or complex numbers. I will discuss recent progress on non-archimedean tame geometry. I will present analogues of o-minimality\, of Pila-Wilkie’s o-minimal counting results\, and of other finiteness results\, in non-archimedean settings. \n2:00–2:30 pm\nBreak with refreshments (Common Room) \n2:30–3:30 pm\nSpeaker: David Urbanik\, IHES\, France & IAS\nTitle: Degrees of Hodge Loci \n\n    \n  \n  URL:https://cmsa.fas.harvard.edu/event/geophys/ LOCATION:CMSA Room G10\, CMSA\, 20 Garden Street\, Cambridge\, MA\, 02138\, United States CATEGORIES:Conference,Event,Workshop ATTACH;FMTTYPE=image/jpeg:https://cmsa.fas.harvard.edu/media/Geophys_poster.4-scaled.jpg END:VEVENT BEGIN:VEVENT DTSTART;TZID=America/New_York:20251110T150000 DTEND;TZID=America/New_York:20251110T160000 DTSTAMP:20260702T074049 CREATED:20251014T143715Z LAST-MODIFIED:20251103T155540Z UID:10003814-1762786800-1762790400@cmsa.fas.harvard.edu SUMMARY:The Moyal bracket and the BV cohomology of the spinning particle DESCRIPTION:Quantum Field Theory and Physical Mathematics Seminar \nSpeaker: Ezra Getzler\, Northwestern \nTitle: The Moyal bracket and the BV cohomology of the spinning particle \nAbstract: The spinning particle is the one-dimensional reduction of the Neveu-Schwartz-Ramond superstring. It consists of a supersymmetric particle moving in a one-dimensional supergravity background\, and its quantization is the Hilbert superspace of harmonic spinors. (These models are classified by N\, the number of copies of fermionic fields. In this talk\, N=1. The extension to N=2 is work in progress with Ivo.) It is actually an AKSZ model (so a generalization of one-dimensional Chern-Simons)\, and so associated to a differential graded symplectic supermanifold\, by which we mean a pair (ω\,Q)\, where ω is a(n exact) symplectic form and Q is an odd function of degree 1. The cohomology of the ring of functions of this supermanifold with differential the Poisson bracket  with Q determines the classical BV cohomology of the spinning particle\, so is important for understanding perturbative BV quantization of this model. I calculated this cohomology in earlier work for N=1\, and showed that it is somewhat bizarre\, with two series of cohomology classes in arbitrary negative degrees\, each a copy of the functions on the target manifold. \nIn the study of quantum BFV\, we should instead consider the Moyal bracket on the target\, and lift Q to an element Q satisfying [Q\,Q]=0. The cohomology of the differential [Q\,-] is the Moyal cohomology of the differential graded symplectic supermanifold. (This lift corresponds to the choice of a Spinc structure on the target manifold.) In this talk\, I prove that the Moyal cohomology\, unlike the Poisson cohomology\, is well-behaved: in the spectral sequence from Poisson to Moyal cohomology\, the extra cohomology classes of negative degree cancel each other pairwise at the E1 page. \n  URL:https://cmsa.fas.harvard.edu/event/qft_111025/ 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-11.10.25-scaled.png END:VEVENT BEGIN:VEVENT DTSTART;TZID=America/New_York:20251106T160000 DTEND;TZID=America/New_York:20251106T170000 DTSTAMP:20260702T074049 CREATED:20250904T163021Z LAST-MODIFIED:20251104T160806Z UID:10003784-1762444800-1762448400@cmsa.fas.harvard.edu SUMMARY:Dimension Reduction and Adiabatic Limits of Generalized ASD Instantons DESCRIPTION:Differential Geometry and Physics Seminar \nSpeaker: Dylan Galt\, Harvard \nTitle: Dimension Reduction and Adiabatic Limits of Generalized ASD Instantons \nAbstract: I will begin by explaining a dimension reduction result for Tian’s generalized ASD instantons over product manifolds\, which generalizes work of Yuanqi Wang on codimension-one reduction and includes the cases of G2 and Spin(7) instantons as well as degree zero Hermitian-Yang-Mills connections. The proof is inspired by a simple observation about the Yang-Mills energy and suggests a natural adiabatic picture for these generalized ASD connections. I will describe ongoing work towards establishing such an adiabatic scheme\, emphasizing some of the complications that arise in the general case and explaining what can be said for G2 instantons. Everything I will talk about is joint work with my collaborator Langte Ma. \n  URL:https://cmsa.fas.harvard.edu/event/dgphys_11625/ 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-11.6.2025.docx-scaled.png END:VEVENT BEGIN:VEVENT DTSTART;TZID=America/New_York:20251030T160000 DTEND;TZID=America/New_York:20251030T170000 DTSTAMP:20260702T074049 CREATED:20250904T162918Z LAST-MODIFIED:20251027T145519Z UID:10003782-1761840000-1761843600@cmsa.fas.harvard.edu SUMMARY:RCD structures on singular Kahler varieties DESCRIPTION:Differential Geometry and Physics Seminar \nSpeaker: Jian Song\, Rutgers University \nTitle: RCD structures on singular Kahler varieties \nAbstract: Let X be a 3-dimensional projective variety with klt singularities. We prove that every singular Kahler metric on X with bounded Nash entropy and Ricci curvature bounded below induces a unique compact RCD space homeomorphic to the projective variety X itself. In particular\, singular Kahler- Einstein spaces of complex dimension 3 with bounded Nash entropy are compact RCD spaces topologically and holomorphically equivalent to the underlying projective variety.  Such results establish connections among algebraic\, geometric and analytic structures of klt singularities from birational geometry and provide abundant examples of RCD spaces from algebraic geometry via complex Monge-Ampere equations. URL:https://cmsa.fas.harvard.edu/event/dgphys_103025/ 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-10.30.2025-scaled.png END:VEVENT BEGIN:VEVENT DTSTART;TZID=America/New_York:20251030T140000 DTEND;TZID=America/New_York:20251030T150000 DTSTAMP:20260702T074049 CREATED:20251014T143046Z LAST-MODIFIED:20251030T144718Z UID:10003812-1761832800-1761836400@cmsa.fas.harvard.edu SUMMARY:Affine Springer fibers and representations DESCRIPTION:Algebra Seminar \nSpeaker: Roman Bezrukavnikov\, MIT \nTitle: Affine Springer fibers and representations \nAbstract: Relating representation categories of interest\, such of modules over the quantum group\, to topology of loop spaces has been an important theme in representation theory for some decades. I will describe a result of this sort involving a geometric object that has not appeared in this context until now\, an affine Springer fiber\, and mention its applications. Based on a joint work with Pablo Boixeda Alvarez\, Michael McBreen and Zhiwei Yun. \n  \n  URL:https://cmsa.fas.harvard.edu/event/algebra-seminar_103025/ LOCATION:CMSA Room G10\, CMSA\, 20 Garden Street\, Cambridge\, MA\, 02138\, United States CATEGORIES:Algebra Seminar ATTACH;FMTTYPE=image/png:https://cmsa.fas.harvard.edu/media/CMSA-Algebra-Seminar-10.30.25.docx-2-scaled.png END:VEVENT BEGIN:VEVENT DTSTART;TZID=America/New_York:20251027T163000 DTEND;TZID=America/New_York:20251027T173000 DTSTAMP:20260702T074049 CREATED:20250911T192619Z LAST-MODIFIED:20250911T193132Z UID:10003793-1761582600-1761586200@cmsa.fas.harvard.edu SUMMARY:Rigidity\, expansion and polytopes DESCRIPTION:Colloquium \nSpeaker: Eran Nevo (Hebrew University of Jerusalem) \nTitle: Rigidity\, expansion and polytopes \nAbstract: Given a graph G and an embedding of its vertices in R^d\, what continuous motions of the vertices preserve all edge lengths? Clearly all motions induced by an isometry of R^d do\, these are the trivial motions; are there any others? If the answer is NO for all (equivalently\, for one) generic embedding\, G is called d-rigid. \nWhat are the d-rigid graphs? \nThis problem has been extensively studied since the 70s\, and is still widely open for d≥3. It is studied mainly from algebraic geometry and combinatorial points of view. Variants of it\, especially in dimensions 2 and 3\, are of importance also beyond mathematics\, e.g. in structural engineering\, computational biology and more. \nI will focus on a quantitative version of rigidity via spectral analysis of the related stiffness matrix\, including the construction of “rigidity expanders”\, generalizing expander graphs. Higher dimensional notions of rigidity and of stiffness matrices\, and their relation to the study of polytopes\, will be addressed too. URL:https://cmsa.fas.harvard.edu/event/colloquium_102725/ 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-10.27.2025.png END:VEVENT BEGIN:VEVENT DTSTART;TZID=America/New_York:20251027T150000 DTEND;TZID=America/New_York:20251027T160000 DTSTAMP:20260702T074049 CREATED:20250924T183029Z LAST-MODIFIED:20251024T144939Z UID:10003798-1761577200-1761580800@cmsa.fas.harvard.edu SUMMARY:de Rham Theory in Derived Differential Geometry DESCRIPTION:Quantum Field Theory and Physical Mathematics Seminar \nSpeaker: Grigorii Taroian\, U Toronto \nTitle: de Rham Theory in Derived Differential Geometry \nAbstract: In the talk\, I will describe recent progress in building a version of de Rham theory for derived manifolds and derived differentiable stacks.\nDerived differential geometry is a nascent field applying techniques from derived algebraic geometry to the study of spaces with smooth structures. As such\, it serves as a natural home for studying objects arising in BV formalism. For instance\, concepts such as critical loci of action functionals or their quotients by gauge actions can be naturally interpreted as derived differentiable stacks.\nIn our work\, we build a version of de Rham theory for these spaces and prove a version of the de Rham isomorphism. Due to the highly singular nature of all objects involved\, developing such a theory is significantly more challenging than in the usual differential geometry\, and thus\, we construct our formalism with inspiration from algebraic geometry rather than classical differential topology. As a main application of the developed theory\, we obtain a version of the comparison morphism between de Rham and constant sheaf cohomology arising from the corresponding map of stacks. This should enable further developments\, with a view towards a fully-fledged theory of shifted symplectic structures for derived differentiable stacks.\nThe talk is based on a preprint of the same name\, arXiv:2505.03978. URL:https://cmsa.fas.harvard.edu/event/qft_102725/ 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-10.27.25-scaled.png END:VEVENT BEGIN:VEVENT DTSTART;TZID=America/New_York:20251023T160000 DTEND;TZID=America/New_York:20251023T170000 DTSTAMP:20260702T074049 CREATED:20250904T162649Z LAST-MODIFIED:20251021T144005Z UID:10003781-1761235200-1761238800@cmsa.fas.harvard.edu SUMMARY:On some new irrationality results DESCRIPTION:Differential Geometry and Physics Seminar \nSpeaker: Ron Donagi\, UPenn \nTitle: On some new irrationality results \nAbstract: An algebraic variety X is rational if a Zariski-open subset of X is isomorphic to a Zariski-open subset of projective space. A weaker property is unirationality: X is unirational if a Zariski-open subset of projective space maps onto a Zariski-open subset of X. These properties are equivalent in dimensions 1 and 2. In the seventies it was discovered that they are not equivalent in dimension 3\, as several different approaches succeeded in proving irrationality of some unirational varieties. The theory of Hodge atoms\, recently developed by Katzarkov\, Kontsevich\, Pantev and Yu\, uses ideas from mirror symmetry and quantum cohomology to exhibit new birational invariants capable of proving irrationality of some 4-dimensional unirational varieties. We illustrate the power of this new technique by applying it to the 4 dimensional intersection of quadrics in P^7. \n  \n  URL:https://cmsa.fas.harvard.edu/event/dgphys_102325/ 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-10.23.2025.docx-1-scaled.png END:VEVENT BEGIN:VEVENT DTSTART;TZID=America/New_York:20251023T140000 DTEND;TZID=America/New_York:20251023T150000 DTSTAMP:20260702T074049 CREATED:20250911T184605Z LAST-MODIFIED:20251021T143543Z UID:10003791-1761228000-1761231600@cmsa.fas.harvard.edu SUMMARY:Character sheaves on the loop Lie algebra and its global implications DESCRIPTION:Algebra Seminar \nSpeaker: Zhiwei Yun\, MIT \nTitle: Character sheaves on the loop Lie algebra and its global implications \nAbstract: Motivated by Lusztig’s definition of character sheaves on a reductive Lie algebra\, we propose a definition of character sheaves on the loop Lie algebra. The construction can be viewed as a p-adic analogue of the orbit method\, and the resulting sheaves are closely related to characters of supercuspidal representations of J.K.Yu. Further\, the construction suggests a definition of wildly ramified Hitchin moduli spaces suitable for the study of ramified geometric Langlands. This is joint work with Bao Chau Ngo. \n  URL:https://cmsa.fas.harvard.edu/event/algebra-seminar_102325/ LOCATION:CMSA Room G10\, CMSA\, 20 Garden Street\, Cambridge\, MA\, 02138\, United States CATEGORIES:Algebra Seminar ATTACH;FMTTYPE=image/png:https://cmsa.fas.harvard.edu/media/CMSA-Algebra-Seminar-10.23.25-scaled.png END:VEVENT BEGIN:VEVENT DTSTART;TZID=America/New_York:20251020T150000 DTEND;TZID=America/New_York:20251020T160000 DTSTAMP:20260702T074049 CREATED:20250924T183004Z LAST-MODIFIED:20251016T160042Z UID:10003797-1760972400-1760976000@cmsa.fas.harvard.edu SUMMARY:Categorical 't Hooft expansion and Chiral Algebras DESCRIPTION:Quantum Field Theory and Physical Mathematics Seminar \nSpeaker: Adrian López-Raven\, Perimeter \nTitle: Categorical ‘t Hooft expansion and Chiral Algebras \nAbstract: In https://arxiv.org/abs/2411.00760\, we show how holographic dual B-model backgrounds can be systematically derived from the ‘t Hooft expansion of specific families of chiral algebras. The resulting holographic dual backgrounds are typically non-commutative and appear to be novel. In this talk I’ll review certain aspects of our construction. In particular\, we’ll review how to build a category of D-branes for the String Theory dual\, starting from the planar limit of the chiral algebra. Given its generality\, I’ll emphasize the potential utility of the construction in the study of weak coupling holography for general theories with a large N limit. \n  \n  URL:https://cmsa.fas.harvard.edu/event/qft_102025/ 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-10.20.25-scaled.png END:VEVENT BEGIN:VEVENT DTSTART;TZID=America/New_York:20251016T160000 DTEND;TZID=America/New_York:20251016T170000 DTSTAMP:20260702T074049 CREATED:20250904T162550Z LAST-MODIFIED:20251014T150012Z UID:10003780-1760630400-1760634000@cmsa.fas.harvard.edu SUMMARY:Differential Geometry and Physics Seminar DESCRIPTION:Differential Geometry and Physics Seminar \nSpeaker: Andy Neitzke\, Yale \nTitle: Abelianization of tau functions \nAbstract: The symplectic and hyperkahler geometry of moduli spaces of flat connections over Riemann surfaces is in a sense quantized by the theory of isomonodromic tau functions. These functions in turn arise as partition functions in the conformal field theory of twisted free fermions. I will describe a new scheme for computing these tau functions via abelianization\, and what it produces in one simple example\, related to the Painleve I equation. This scheme is joint work with Qianyu Hao. The talk is intended to be self-contained (you don’t have to know in advance what a tau function or a conformal field theory is). \n  \n  URL:https://cmsa.fas.harvard.edu/event/dgphys_101625/ 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-10.16.2025-scaled.png END:VEVENT BEGIN:VEVENT DTSTART;TZID=America/New_York:20251009T160000 DTEND;TZID=America/New_York:20251009T170000 DTSTAMP:20260702T074049 CREATED:20250904T162516Z LAST-MODIFIED:20251010T130239Z UID:10003779-1760025600-1760029200@cmsa.fas.harvard.edu SUMMARY:Symmetries and Moduli Spaces: Baby Steps beyond Calabi-Yau DESCRIPTION:Differential Geometry and Physics Seminar \nSpeaker: Xingyang Yu\, Virginia Tech \nTitle: Symmetries and Moduli Spaces: Baby Steps beyond Calabi-Yau \nAbstract: I will explore the interplay between symmetries and moduli spaces in string compactifications\, starting from the familiar Calabi–Yau case and then taking some baby steps toward more general settings. A classical benchmark is the line bundle over Calabi–Yau complex structure moduli space\, whose physical counterpart corresponds to the Berry phase of the spectral flow operator in worldsheet SCFT. I will review this story and then discuss how it begins to change in c=1 theories with worldsheet anomalies\, and in G_2 and Spin(7) compactifications where U(1)_R symmetry is absent. The goal is not a finished framework\, but to highlight how anomalies and non-invertible symmetries may enter the picture and to raise open questions about what kinds of structures might live over moduli spaces beyond Calabi–Yau. URL:https://cmsa.fas.harvard.edu/event/dgphys_10925/ 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-9.9.2025-scaled.png END:VEVENT BEGIN:VEVENT DTSTART;TZID=America/New_York:20251009T140000 DTEND;TZID=America/New_York:20251009T150000 DTSTAMP:20260702T074049 CREATED:20250911T184457Z LAST-MODIFIED:20251002T182058Z UID:10003789-1760018400-1760022000@cmsa.fas.harvard.edu SUMMARY:Profinite tensor powers DESCRIPTION:Algebra Seminar \nSpeaker: David Treumann (Boston College) \nTitle: Profinite tensor powers \nAbstract: I’ll discuss the problem of defining a tensor product of profinitely many copies of a vector space V\, and propose a definition $\bigotimes_X^{mcc} V$ in the special situation that (1) V is finite-dimensional over F_2\, and (2) the profinite X indexing the tensor factors is acted on with finitely many orbits by a pro-2-group. The “mcc” on the tensor sign stands for “magnetized and conditionally convergent.” A variant construction makes sense when V is a bimodule over a semisimple F_2-algebra\, and the index set X has the profinite version of a cyclic order. The definition organizes some computations in Heegard Floer homology: it can be pitched as a computation of the HF of some pro-3-manifolds\, though we do not know how to define such a thing. This is joint work with CM Michael Wong. \n  URL:https://cmsa.fas.harvard.edu/event/algebra-seminar_10925/ LOCATION:CMSA Room G10\, CMSA\, 20 Garden Street\, Cambridge\, MA\, 02138\, United States CATEGORIES:Algebra Seminar ATTACH;FMTTYPE=image/png:https://cmsa.fas.harvard.edu/media/CMSA-Algebra-Seminar-10.9.25-scaled.png END:VEVENT BEGIN:VEVENT DTSTART;TZID=America/New_York:20251006T163000 DTEND;TZID=America/New_York:20251006T173000 DTSTAMP:20260702T074049 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:20251002T160000 DTEND;TZID=America/New_York:20251002T170000 DTSTAMP:20260702T074049 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:20250929T150000 DTEND;TZID=America/New_York:20250929T160000 DTSTAMP:20260702T074049 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:20250925T160000 DTEND;TZID=America/New_York:20250925T170000 DTSTAMP:20260702T074049 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:20250922T163000 DTEND;TZID=America/New_York:20250922T173000 DTSTAMP:20260702T074049 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:20250922T150000 DTEND;TZID=America/New_York:20250922T160000 DTSTAMP:20260702T074049 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:20250918T160000 DTEND;TZID=America/New_York:20250918T170000 DTSTAMP:20260702T074049 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:20250915T163000 DTEND;TZID=America/New_York:20250915T173000 DTSTAMP:20260702T074049 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:20250915T150000 DTEND;TZID=America/New_York:20250915T160000 DTSTAMP:20260702T074049 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:20250911T090000 DTEND;TZID=America/New_York:20250912T170000 DTSTAMP:20260702T074049 CREATED:20250502T175902Z LAST-MODIFIED:20251026T044243Z UID:10003743-1757581200-1757696400@cmsa.fas.harvard.edu SUMMARY:Big Data Conference 2025 DESCRIPTION:Big Data Conference 2025 \nDates: Sep. 11–12\, 2025 \nLocation: Harvard University CMSA\, 20 Garden Street\, Cambridge & via Zoom \nThe Big Data Conference features speakers from the Harvard community as well as scholars from across the globe\, with talks focusing on computer science\, statistics\, math and physics\, and economics. \nInvited Speakers \n\nMarkus J. Buehler\, MIT\nYiling Chen\, Harvard\nJordan Ellenberg\, UW Madison\nYue M. Lu\, Harvard\nPankaj Mehta\, BU\nNick Patterson\, Harvard\nGautam Reddy\, Princeton\nTrevor David Rhone\, Rensselaer Polytechnic Institute\nTess Smidt\, MIT\n\nOrganizers: \nMichael M. Desai\, Harvard OEB |  Michael R. Douglas\, Harvard CMSA | Yannai A. Gonczarowski\, Harvard Economics | Efthimios Kaxiras\, Harvard Physics | Melanie Weber\, Harvard SEAS \n  \nBig Data Youtube Playlist \n  \nSchedule \nThursday\, Sep. 11\, 2025 \n  \n\n\n\n9:00 am\nRefreshments\n\n\n9:30 am\nIntroductions\n\n\n9:45–10:45 am\nGautam Reddy\, Princeton \nTitle: Global epistasis in genotype-phenotype maps\n\n\n10:45–11:00 am\nBreak\n\n\n11:00 am –12:00 pm\nNick Patterson\, Harvard \nTitle: The Origin of the Indo-Europeans \nAbstract: Indo-European is the largest family of human languages\, with very wide geographical distribution and more than 3 billion native speakers. How did this family arise and spread? This question has been discussed for nearly 250 years but with the advent of the availability of DNA from ancient fossils is now largely understood\, at least in broad outlines. We will describe what we now know about the origins.\n\n\n12:00–1:30 pm\nLunch break\n\n\n1:30–2:30 pm\nMarkus Buehler\, MIT \nTitle: Superintelligence for scientific discovery \nAbstract: AI is moving beyond prediction to become a partner in invention. While today’s models excel at interpolating within known data\, true discovery requires stepping outside existing truths. This talk introduces superintelligent discovery engines built on multi-agent swarms: diverse AI agents that interact\, compete\, and cooperate to generate structured novelty. Guided by Gödel’s insight that no closed system is complete\, these swarms create gradients of difference – much like temperature gradients in thermodynamics – that sustain flow\, invention\, and surprise. Case studies in protein design and music composition show how swarms escape data biases\, invent novel structures\, and weave long-range coherence\, producing creativity that rivals human processes. By moving from “big data” to “big insight”\, these systems point toward a new era of AI that composes knowledge across science\, engineering\, and the arts.\n\n\n2:30–2:45 pm\nBreak\n\n\n2:45–3:45 pm\nJordan Ellenberg\, UW Madison \nTitle: What does machine learning have to offer mathematics?\n\n\n3:45–4:00 pm\nBreak\n\n\n4:00–5:00 pm\nPankaj Mehta\, Boston University \nTitle: Thinking about high-dimensional biological data in the age of AI \nAbstract: The molecular biology revolution has transformed our view of living systems. Scientific explanations of biological phenomena are now synonymous with the identification of the genes and proteins. The preeminence of the molecular paradigm has only become more pronounced as new technologies allow us to make measurements at scale. Combining this wealth of data with new artificial intelligence (AI) techniques is widely viewed as the future of biology. Here\, I will discuss the promise and perils of this approach. I will focus on our unpublished work with collaborators on two fronts: (i) transformer-based models for understanding genotype-to-phenotype maps\, and (ii) LLM-based ‘foundational models’ for cellular identity\, such as TranscriptFormer\, which is trained on single-cell RNA sequencing (scRNAseq) data. While LLMs excel at capturing complex evolutionary and demographic structure in DNA sequence data\, they are much less adept at elucidating the biology of cellular identity. We show that simple parameter-free models based on linear-algebra outperform TranscriptFormer on downstream tasks related to cellular identity\, even though TranscriptFormer has nearly a billion parameters. If time permits\, I will conclude by showing how we can combine ideas from linear algebra\, bifurcation theory\, and statistical physics to classify cell fate transitions using scRNAseq data.\n\n\n\n  \nFriday\, Sep. 12\, 2025  \n\n\n\n9:00-9:45 am\nRefreshments\n\n\n9:45–10:45 am\nYiling Chen\, Harvard \nTitle: Data Reliability Scoring \nAbstract: Imagine you are trying to make a data-driven decision\, but the data at hand may be noisy\, biased\, or even strategically manipulated. Can you assess whether such a dataset is reliable—without access to ground truth?\nWe initiate the study of reliability scoring for datasets reported by potentially strategic data sources. While the true data remain unobservable\, we assume access to auxiliary observations generated by an unknown statistical process that depends on the truth. We introduce the Gram Determinant Score\, a reliability measure that evaluates how well the reported data align with the unobserved truth\, using only the reported data and the auxiliary observations. The score comes with provable guarantees: it preserves several natural reliability orderings. Experimentally\, it effectively captures data quality in settings with synthetic noise and contrastive learning embeddings.\nThis talk is based on joint work with Shi Feng\, Fang-Yi Yu\, and Paul Kattuman.\n\n\n10:45–11:00 am\nBreak\n\n\n11:00 am –12:00 pm\nYue M. Lu\, Harvard \nTitle: Nonlinear Random Matrices in High-Dimensional Estimation and Learning \nAbstract: In recent years\, new classes of structured random matrices have emerged in statistical estimation and machine learning. Understanding their spectral properties has become increasingly important\, as these matrices are closely linked to key quantities such as the training and generalization performance of large neural networks and the fundamental limits of high-dimensional signal recovery. Unlike classical random matrix ensembles\, these new matrices often involve nonlinear transformations\, introducing additional structural dependencies that pose challenges for traditional analysis techniques. \nIn this talk\, I will present a set of equivalence principles that establish asymptotic connections between various nonlinear random matrix ensembles and simpler linear models that are more tractable for analysis. I will then demonstrate how these principles can be applied to characterize the performance of kernel methods and random feature models across different scaling regimes and to provide insights into the in-context learning capabilities of attention-based Transformer networks.\n\n\n12:00–1:30 pm\nLunch break\n\n\n1:30–2:30 pm\nTrevor David Rhone\, Rensselaer Polytechnic Institute \nTitle: Accelerating the discovery of van der Waals quantum materials using AI \nAbstract: van der Waals (vdW) materials are exciting platforms for studying emergent quantum phenomena\, ranging from long-range magnetic order to topological order. A conservative estimate for the number of candidate vdW materials exceeds ~106 for monolayers and ~1012 for heterostructures. How can we accelerate the exploration of this entire space of materials? Can we design quantum materials with desirable properties\, thereby advancing innovation in science and technology? A recent study showed that artificial intelligence (AI) can be harnessed to discover new vdW Heisenberg ferromagnets based on Cr2Ge2Te6 [1]\, [2] and magnetic vdW topological insulators based on MnBi2Te4 [3]. In this talk\, we will harness AI to efficiently explore the large chemical space of vdW materials and to guide the discovery of vdW materials with desirable spin and charge properties. We will focus on crystal structures based on monolayer Cr2I6 of the form A2X6\, which are studied using density functional theory (DFT) calculations and AI. Magnetic properties\, such as the magnetic moment are determined. The formation energy is also calculated and used as a proxy for the chemical stability. We also investigate monolayers based on MnBi2Te4 of the form AB2X4 to identify novel topological materials. Further to this\, we study heterostructures based on MnBi2Te4/Sb2Te3 stacks. We show that AI\, combined with DFT\, can provide a computationally efficient means to predict the thermodynamic and magnetic properties of vdW materials [4]\,[5]. This study paves the way for the rapid discovery of chemically stable vdW quantum materials with applications in spintronics\, magnetic memory and novel quantum computing architectures.\n[1]        T. D. Rhone et al.\, “Data-driven studies of magnetic two-dimensional materials\,” Sci. Rep.\, vol. 10\, no. 1\, p. 15795\, 2020.\n[2]        Y. Xie\, G. Tritsaris\, O. Granas\, and T. Rhone\, “Data-Driven Studies of the Magnetic Anisotropy of Two-Dimensional Magnetic Materials\,” J. Phys. Chem. Lett.\, vol. 12\, no. 50\, pp. 12048–12054.\n[3]        R. Bhattarai\, P. Minch\, and T. D. Rhone\, “Investigating magnetic van der Waals materials using data-driven approaches\,” J. Mater. Chem. C\, vol. 11\, p. 5601\, 2023.\n[4]        T. D. Rhone et al.\, “Artificial Intelligence Guided Studies of van der Waals Magnets\,” Adv. Theory Simulations\, vol. 6\, no. 6\, p. 2300019\, 2023.\n[5]        P. Minch\, R. Bhattarai\, K. Choudhary\, and T. D. Rhone\, “Predicting magnetic properties of van der Waals magnets using graph neural networks\,” Phys. Rev. Mater.\, vol. 8\, no. 11\, p. 114002\, Nov. 2024.\nThis work used the Extreme Science and Engineering Discovery Environment (XSEDE)\, which is supported by National Science Foundation Grant No. ACI-1548562. This research used resources of the Argonne Leadership Computing Facility\, which is a DOE Office of Science User Facility supported under Contract No. DE-AC02-06CH11357. This material is based on work supported by the National Science Foundation CAREER award under Grant No. 2044842.\n\n\n2:30–2:45 pm\nBreak\n\n\n2:45–3:45 pm\nTess Smidt\, MIT \nTitle: Applications of Euclidean neural networks to understand and design atomistic systems \nAbstract: Atomic systems (molecules\, crystals\, proteins\, etc.) are naturally represented by a set of coordinates in 3D space labeled by atom type. This poses a challenge for machine learning due to the sensitivity of coordinates to 3D rotations\, translations\, and inversions (the symmetries of 3D Euclidean space). Euclidean symmetry-equivariant Neural Networks (E(3)NNs) are specifically designed to address this issue. They faithfully capture the symmetries of physical systems\, handle 3D geometry\, and operate on the scalar\, vector\, and tensor fields that characterize these systems. \nE(3)NNs have achieved state-of-the-art results across atomistic benchmarks\, including small-molecule property prediction\, protein-ligand binding\, force prediciton for crystals\, molecules\, and heterogeneous catalysis. By merging neural network design with group representation theory\, they provide a principled way to embed physical symmetries directly into learning. In this talk\, I will survey recent applications of E(3)NNs to materials design and highlight ongoing debates in the AI for atomistic sciences community: how to balance the incorporation of physical knowledge with the drive for engineering efficiency.\n\n\n\n  URL:https://cmsa.fas.harvard.edu/event/bigdata_2025/ LOCATION:CMSA Room G10\, CMSA\, 20 Garden Street\, Cambridge\, MA\, 02138\, United States CATEGORIES:Big Data Conference,Conference,Event ATTACH;FMTTYPE=image/jpeg:https://cmsa.fas.harvard.edu/media/Big-Data-2025_11x17.9-scaled.jpg END:VEVENT BEGIN:VEVENT DTSTART;TZID=America/New_York:20250516T120000 DTEND;TZID=America/New_York:20250516T130000 DTSTAMP:20260702T074049 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:20250515T100000 DTEND;TZID=America/New_York:20250515T110000 DTSTAMP:20260702T074049 CREATED:20250417T165100Z LAST-MODIFIED:20250509T175206Z UID:10003741-1747303200-1747306800@cmsa.fas.harvard.edu SUMMARY:Resurgence\, number theory\, and quantum mirror curves  DESCRIPTION:Mathematical Physics and Algebraic Geometry Seminar \nSpeaker: Claudia Rella (IHES) \nTitle: Resurgence\, number theory\, and quantum mirror curves \nAbstract: Resurgence provides a powerful toolbox to access the non-perturbative sectors hidden within the divergent asymptotic series of quantum theories. Under some special assumptions\, the non-perturbative data extracted via resurgent methods possess intrinsic number-theoretic properties that are deeply rooted in the symmetries and arithmetic of the geometry underlying the quantum theory. The framework of modular resurgence aims to formalise this observation. In this talk\, after introducing the basics of modular resurgence\, I will consider the TS/ST correspondence for toric Calabi-Yau threefolds and focus on the fermionic spectral traces of quantum mirror curves. Here\, a complete realisation of the modular resurgence paradigm is found in the spectral theory of local P^2—where the bridge between non-perturbative physics and the arithmetic properties of the geometry takes the form of an exact strong-weak symmetry—and is now being generalised to all local weighted projective spaces. This talk is based on arXiv:2212.10606\, 2404.10695\, 2404.11550\, and work in progress. \n  \n  \n  URL:https://cmsa.fas.harvard.edu/event/mathphys_51525/ 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-5.15.2025.png END:VEVENT END:VCALENDAR