BEGIN:VCALENDAR
VERSION:2.0
PRODID:-//CMSA - ECPv6.15.18//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: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:20251001T140000
DTEND;TZID=America/New_York:20251001T150000
DTSTAMP:20260501T175305
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:20260501T175305
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:20260501T175305
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:20260501T175305
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:20260501T175305
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:20260501T175305
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:20260501T175305
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
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20251009T140000
DTEND;TZID=America/New_York:20251009T150000
DTSTAMP:20260501T175305
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:20251009T160000
DTEND;TZID=America/New_York:20251009T170000
DTSTAMP:20260501T175305
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:20251010T120000
DTEND;TZID=America/New_York:20251010T130000
DTSTAMP:20260501T175306
CREATED:20250827T140826Z
LAST-MODIFIED:20251006T190823Z
UID:10003765-1760097600-1760101200@cmsa.fas.harvard.edu
SUMMARY:The Rozansky-Witten field theory in the functorial TQFT formalism
DESCRIPTION:Member Seminar \nSpeaker: Lorenzo Riva \nTitle: The Rozansky-Witten field theory in the functorial TQFT formalism \nAbstract: This will be a broad talk about the topic of my PhD thesis. We will discuss a particular example of a 3D field theory from physics called Rozansky-Witten which is interesting from both a physical and a mathematical point of view: its is connected with mirror symmetry\, the A- and B-models\, Calabi-Yau geometry\, and the partition functions give finite-type invariants of 3-manifolds. In the rest of the talk we will try to formalize this field theory as a functor out of a certain cobordism 3-category (emphasis on “try”).
URL:https://cmsa.fas.harvard.edu/event/member-seminar-101025/
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-10.10.25-scaled.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20251014T161500
DTEND;TZID=America/New_York:20251014T183000
DTSTAMP:20260501T175306
CREATED:20251001T183159Z
LAST-MODIFIED:20251014T154228Z
UID:10003803-1760458500-1760466600@cmsa.fas.harvard.edu
SUMMARY:Geometry and Quantum Theory Seminar
DESCRIPTION:Geometry and Quantum Theory Seminar \nSpeaker: Dylan Galt\, Harvard \n(60 minute talk) \nTitle: What is a “nonlinear” near-symplectic form? \nAbstract: In this talk\, I will explain how one might understand this question and why a possible answer can be found in the geometry of coassociative 4-folds\, a special class of minimal submanifolds discovered by Harvey and Lawson. \n  \nSpeaker: Keyou Zeng\, CMSA \n(30 minute talk) \nTitle: Cohomology of configuration space of points \nAbstract: Configuration space of points is an interesting and important subject in mathematics and physics. I’ll review some classical results computing cohomology of configuration space of points. I’ll also introduce some recent progress in computing sheaf cohomology of configuration space of affine space. \n  \n 
URL:https://cmsa.fas.harvard.edu/event/quantumgeo_101425/
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-10.14.25-scaled.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20251016T140000
DTEND;TZID=America/New_York:20251016T150000
DTSTAMP:20260501T175306
CREATED:20250911T184527Z
LAST-MODIFIED:20251006T162709Z
UID:10003790-1760623200-1760626800@cmsa.fas.harvard.edu
SUMMARY:Lech's inequality and stability of local rings
DESCRIPTION:Algebra Seminar \nSpeaker: Linquan Ma (Purdue University) \nTitle: Lech’s inequality and stability of local rings \nAbstract: We explore Lech’s inequality relating the colength and multiplicity of m-primary ideals in a Noetherian local ring (R\,m). We introduce a natural invariant that measures the sharpness of Lech’s inequality and show its connections with singularities of asymptotically semistable varieties and singularities arising from the MMP. We compute this invariant in various examples. This is joint work with Ilya Smirnov. \n 
URL:https://cmsa.fas.harvard.edu/event/algebra-seminar_101625/
LOCATION:Virtual
CATEGORIES:Algebra Seminar
ATTACH;FMTTYPE=image/png:https://cmsa.fas.harvard.edu/media/CMSA-Algebra-Seminar-10.16.25.docx-1-1-scaled.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20251016T160000
DTEND;TZID=America/New_York:20251016T170000
DTSTAMP:20260501T175306
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:20251017T120000
DTEND;TZID=America/New_York:20251017T130000
DTSTAMP:20260501T175306
CREATED:20250827T141359Z
LAST-MODIFIED:20251010T180544Z
UID:10003766-1760702400-1760706000@cmsa.fas.harvard.edu
SUMMARY:DMFT\, Two Point Correlations of Resolvents\, and Applications to Machine Learning Theory
DESCRIPTION:Member Seminar \nSpeaker: Blake Bordelon \nTitle: DMFT\, Two Point Correlations of Resolvents\, and Applications to Machine Learning Theory \nAbstract: Machine learning algorithms evolve the parameters of a model in a high dimensional and disordered loss landscape. To characterize the effects of random initialization of model parameters\, randomly sampled training data\, and the effect of SGD noise\, it often is useful to invoke ideas from random matrix theory and the physics of disordered systems. In this seminar\, I describe a general idea\, known as dynamical mean field theory (DMFT) which describes the evolution of a disordered dynamical system in infinite dimensions. I will briefly describe simple examples of interest to theoretical neuroscientists and machine learning theorists. For linear dynamical systems\, I will show that this method characterizes the typical case trajectory in terms of two point correlations of resolvent matrices evaluated at different frequencies. This bispectral object can account for puzzling effects such as late time divergence of gradient descent at the interpolation threshold (when parameters = dataset size) despite the Jacobian of the dynamics having real and non-positive eigenvalues. I will then describe a novel two point correlation result for general free products of the form M = O B O^T A for O sampled from the Haar measure. I will use this result to characterize the exact asymptotics of the performance of a linear transformer trained to perform in-context linear regression on “generic” (randomly rotated) covariance matrices.
URL:https://cmsa.fas.harvard.edu/event/member-seminar-101725/
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-10.17.25-scaled.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20251017T130000
DTEND;TZID=America/New_York:20251017T160000
DTSTAMP:20260501T175306
CREATED:20250930T134721Z
LAST-MODIFIED:20251014T133421Z
UID:10003800-1760706000-1760716800@cmsa.fas.harvard.edu
SUMMARY:Freedman Seminar: Michael Freedman\, CMSA & Bowen Yang\, CMSA
DESCRIPTION:Freedman Seminar \nSpeaker: Michael Freedman\, Harvard CMSA \nTitle: Sullivan’s work on Lipschitz structures \nAbstract: I’ll begin with an elementary\, but now little known\, piece of PL topology: engulfing. John Stalling used it to give an alternative proof of the high dimensional Poincare conjecture. Then I’ll explain Dennis Sullivan’s enhancement of Kirby’s torus trick (which relies on engulfing.) I’ll note an open question regarding Lipschitz structures on 4-manifolds. \n  \nSpeaker: Bowen Yang\, CMSA \nTitle: Quantum Cellular Automata and Algebraic L-Theory \nAbstract: Quantum cellular automata (QCAs) are models of reversible quantum dynamics that preserve locality; they can be thought of as quantum analogues of classical cellular automata\, but with much richer structure. I will describe a classification of the Clifford subclass of QCAs using methods from algebraic L-theory. The main result identifies the group of Clifford QCAs\, up to natural equivalences\, with L-theory homology of the underlying space. This gives a conceptual explanation of previously observed periodic patterns in lattice models and extends the picture to more general spaces. I will outline the ideas behind the construction and indicate how the framework connects topology\, operator algebras\, and quantum information. If time permits\, I will also comment on what is known — and unknown — about the general (non-Clifford) case.
URL:https://cmsa.fas.harvard.edu/event/freedman_101725/
LOCATION:Virtual
CATEGORIES:Freedman Seminar
ATTACH;FMTTYPE=image/png:https://cmsa.fas.harvard.edu/media/CMSA-Freedman-Seminar-10.17.25.docx-1-scaled.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20251020T150000
DTEND;TZID=America/New_York:20251020T160000
DTSTAMP:20260501T175306
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:20251022T120000
DTEND;TZID=America/New_York:20251022T130000
DTSTAMP:20260501T175306
CREATED:20251002T141005Z
LAST-MODIFIED:20251003T205211Z
UID:10003804-1761134400-1761138000@cmsa.fas.harvard.edu
SUMMARY:CMSA Q&A Seminar: Thomas Grimm
DESCRIPTION:CMSA Q&A Seminar \nSpeaker: Thomas Grimm\, Utrecht & CMSA \nTopic: What is o-minimality and what is it good for?
URL:https://cmsa.fas.harvard.edu/event/cmsaqa_102225/
LOCATION:Common Room\, CMSA\, 20 Garden Street\, Cambridge\, MA\, 02138\, United States
CATEGORIES:CMSA Q&A Seminar
ATTACH;FMTTYPE=image/png:https://cmsa.fas.harvard.edu/media/CMSA-Q-A-Seminar-10.22.2025-scaled.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20251022T140000
DTEND;TZID=America/New_York:20251022T150000
DTSTAMP:20260501T175306
CREATED:20251008T132005Z
LAST-MODIFIED:20251008T133142Z
UID:10003808-1761141600-1761145200@cmsa.fas.harvard.edu
SUMMARY:The Carleson project: A collaborative formalization
DESCRIPTION:New Technologies in Mathematics Seminar \nSpeaker: María Inés de Frutos Fernández\, Mathematical Institute\, University of Bonn \nTitle: The Carleson project: A collaborative formalization \nAbstract: A well-known result in Fourier analysis establishes that the partial Fourier sums of a smooth periodic function $f$ converge uniformly to $f$\, but the situation is a lot more subtle for e.g. continuous functions. However\, in 1966 Carleson proved that they do converge at almost all points for $L^2$ periodic functions on the real line. Carleson’s proof is famously hard to read\, and there are no known easy proofs of this theorem. As a large collaborative project\, we have formalized in Lean a generalization of Carleson’s theorem in the setting of doubling metric measure spaces (proven in 2023)\, and Carleson’s original result as a corollary. In this talk I will give an overview of the project\, with a focus on how the collaboration was organized. \n 
URL:https://cmsa.fas.harvard.edu/event/newtech_102225/
LOCATION:Virtual
CATEGORIES:New Technologies in Mathematics Seminar
ATTACH;FMTTYPE=image/png:https://cmsa.fas.harvard.edu/media/CMSA-NTM-Seminar-10.22.2025-scaled.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20251023T140000
DTEND;TZID=America/New_York:20251023T150000
DTSTAMP:20260501T175306
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:20251023T160000
DTEND;TZID=America/New_York:20251023T170000
DTSTAMP:20260501T175306
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:20251024T120000
DTEND;TZID=America/New_York:20251024T130000
DTSTAMP:20260501T175306
CREATED:20250827T141425Z
LAST-MODIFIED:20251020T181711Z
UID:10003767-1761307200-1761310800@cmsa.fas.harvard.edu
SUMMARY:Analytic Spread of Binomial Edge Ideals
DESCRIPTION:Member Seminar \nSpeaker: Stephen Landsittel\, CMSA \nTitle: Analytic Spread of Binomial Edge Ideals \nAbstract: To an ideal J in a polynomial ring R over a field K we associate its analytic spread \ell(J)\, which is the dimension of the fiber cone F(J) of J. When J is graded and generated in a single degree d\, then F(J) is a finite type K-algebra. \nTo a graph G we associate its binomial edge ideal: J_G:= (x_i y_j – x_jy_i | {i\,j} is an edge of G). \nIn this talk we will discuss recent work where sharp bounds are given for \ell(J_G) and we compute the exact value when G is a pseudoforest. We accomplish this by computing the transcendence degree trdeg_{K} F(J)\, of the fiber cone over K.
URL:https://cmsa.fas.harvard.edu/event/member-seminar-102425/
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-10.24.25-scaled.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20251027T150000
DTEND;TZID=America/New_York:20251027T160000
DTSTAMP:20260501T175306
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:20251027T163000
DTEND;TZID=America/New_York:20251027T173000
DTSTAMP:20260501T175306
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:20251028T161500
DTEND;TZID=America/New_York:20251028T183000
DTSTAMP:20260501T175306
CREATED:20251021T201853Z
LAST-MODIFIED:20251027T135640Z
UID:10003818-1761668100-1761676200@cmsa.fas.harvard.edu
SUMMARY:Geometry and Quantum Theory Seminar
DESCRIPTION:Geometry and Quantum Theory Seminar \nSpeakers: (1) Elliott Gesteau\, CMSA (60 min) and  (2) Sanjay Raman\, Harvard (30 min) \n(1) Title: Holography for closed universes \nAbstract: Recent advances in holography and black hole physics have prompted a number of new puzzles related to the physics of closed universes\, which can be argued to have a one-dimensional Hilbert space of states from various perspectives. In this talk I will review this new set of puzzles\, with an emphasis of the mathematical questions that they seem to raise. \n  \n(2) Title: Non-supersymmetric branes\, bordism\, and fractional charges \nAbstract: We dive a little deeper into the non-supersymmetric brane configurations studied in Kaidi-Tachikawa-Yonekura (2024). We study the gravitational analogues of the branes in the aforementioned paper\, relating them to relative defects predicted by the Cobordism Conjecture\, and we argue for the existence of objects carrying fractional heterotic string and M2-brane charge.
URL:https://cmsa.fas.harvard.edu/event/quantumgeo_102825/
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-10.28.25-scaled.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20251030T140000
DTEND;TZID=America/New_York:20251030T150000
DTSTAMP:20260501T175306
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:20251030T160000
DTEND;TZID=America/New_York:20251030T170000
DTSTAMP:20260501T175306
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:20251031T120000
DTEND;TZID=America/New_York:20251031T130000
DTSTAMP:20260501T175306
CREATED:20250827T141457Z
LAST-MODIFIED:20251027T151940Z
UID:10003768-1761912000-1761915600@cmsa.fas.harvard.edu
SUMMARY:Skein remain the same
DESCRIPTION:Member Seminar \nSpeaker: Sunghyuk Park\, CMSA \nTitle: Skein remain the same \nAbstract: The count of holomorphic curves in a Calabi-Yau 3-fold ending on a Lagrangian is famously not deformation invariant\, but Ekholm and Shende have shown that it can be made invariant by counting in the skein. Given a 3-manifold M and a branched cover arising from the projection of a Lagrangian 3-manifold L in the cotangent bundle of M\, we use the skein-valued curve count to construct a map from the skein of M to that of L. When M and L are products of surfaces and intervals\, deforming L within the space of Lagrangians yields a skein-valued lift of the Kontsevich-Soibelman wall-crossing formula. After all\, the skeins remain the same. Based on joint work (arXiv:2510.19041) with Tobias Ekholm\, Pietro Longhi\, and Vivek Shende. \n 
URL:https://cmsa.fas.harvard.edu/event/member-seminar-103125/
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-10.31.25-scaled.png
END:VEVENT
END:VCALENDAR