CMSA

Geometry and Quantum Theory Seminar
2025-05-06 16:15 - 18:15 (America/New_York) | Science Center 507, 1 Oxford Street, Cambridge, 02138

Asset pricing with heterogeneous agents
2025-05-09 12:00 - 13:00 | CMSA Room G10, CMSA, 20 Garden Street, Cambridge, MA, 02138, United States
Member Seminar
Speaker: Sergiy Verstyuk, Harvard CMSA
Title: Asset pricing with heterogeneous agents
Abstract: This talk will introduce the basics of continuous-time finance, discuss important existing theories and models, as well as present some new asset pricing results in a setting with many heterogeneous investors. (Joint work with Puskar Mondal.)

An index for 2d invertible phases of quantum many-body systems
2025-05-12 15:00 - 16:00 | CMSA Room G10, CMSA, 20 Garden Street, Cambridge, MA, 02138, United States
Quantum Field Theory and Physical Mathematics Seminar
Speaker: Nikita Sopenko, IAS
Title: An index for 2d invertible phases of quantum many-body systems

Factorizations for data analysis
2025-05-12 16:30 - 17:30 | CMSA Room G10, CMSA, 20 Garden Street, Cambridge, MA, 02138, United States
Colloquium
Speaker: Anna Seigal, Harvard University
Title: Factorizations for data analysis
Abstract: We can find structure in data by factoring it into building blocks, which should be interpretable for the context at hand. A classical example is principal component analysis (PCA), which uses the eigendecomposition of the covariance matrix to find axes of variation in a dataset. Starting from PCA, I will discuss matrix and tensor factorizations for data analysis, and the linear and multilinear algebra that underpins their theoretical properties. We will see examples from causal inference, independent component analysis, and dimensionality reduction.

Report on the Perimeter Institute Theory+AI Workshop
2025-05-14 12:00 - 13:00 | CMSA 20 Garden Street Cambridge, Massachusetts 02138 United States
Conference Reports
Speaker: Hugo Cui, Harvard CMSA
Title: Report on the Perimeter Institute Theory+AI Workshop
Abstract: I will give a survey and brief summary of some of the talks given at the Theory+AI Workshop: Theoretical Physics for AI event organized by Perimeter Institute in April, on approaches to machine learning theory inspired from physics.
Link : https://events.perimeterinstitute.ca/event/993/

Echo Chamber: RL Post-training Amplifies Behaviors Learned in Pretraining
2025-05-16 12:00 - 13:00 | CMSA Room G10, CMSA, 20 Garden Street, Cambridge, MA, 02138, United States
Member Seminar
Speaker: Samy Jelassi, CMSA
Title: Echo Chamber: RL Post-training Amplifies Behaviors Learned in Pretraining
Abstract: 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.
The 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

Joint BHI/CMSA Foundation Seminar: The semiclassical energy outflux emerging from a collapsing shell
2025-07-31 11:00 - 12:00 | Black Hole Initiative, 20 Garden Street, Cambridge MA, CMSA, 20 Garden Street, Cambridge, MA, 02138, United States
Joint BHI/CMSA Foundation Seminar
Location: BHI seminar room
Speaker: Noa Zilberman (Princeton University)
Title: The semiclassical energy outflux emerging from a collapsing shell
Abstract: When a compact object collapses to form a black hole, quantum field theory predicts the emission of an energy outflux to future null infinity, which later relaxes to Hawking radiation. Within the semiclassical framework, we derive a simple, closed form, analytical expression for the energy outflux emitted from a spherical thin null shell collapsing to form a black hole. In particular, this energy outflux vanishes (quadratically in r-2M) as the shell approaches the horizon. This result refutes claims that the Hawking energy outflux originates from the collapsing body, showing instead that it develops in a broad strong-field region. Additionally, this vanishing implies that semiclassical backreaction cannot prevent or significantly affect the classical process of gravitational collapse and horizon formation (as sometimes claimed).

Fukaya category and gauge theory
2025-09-02 16:15 - 18:30 | Science Center 507, 1 Oxford Street, Cambridge, 02138
Geometry and Quantum Theory Seminar
Speaker: Saman Habibi Esfahani, Harvard CMSA
Title: Fukaya category and gauge theory
Abstract: After setting up some background, I will discuss the Fukaya $A_ infty$-category and several instances where it appears in gauge theory, such as in the study of flat connections on Riemann surfaces, holomorphic sections of some hyperkähler bundles, and instantons and holomorphic curves in K3 surfaces. If time permits, I will also outline potential applications of these ideas to the study of 3-manifolds and manifolds with special holonomy.

Higher categories of cobordisms
2025-09-09 16:15 - 18:30 | Science Center 507, 1 Oxford Street, Cambridge, 02138
Geometry and Quantum Theory Seminar
Speaker: Lorenzo Riva
Title: Higher categories of cobordisms
Abstract: I will give a brief introduction to topological field theories from a higher categorical perspective. After saying a few things about higher categories, I will define a family of n-categories of bordisms and talk about their universal properties. I will try to squeeze in the canonical example — representations of the 2-dimensional oriented bordism 2-category are separable symmetric Frobenius algebras — and, time permitting, talk about my current work.

Orientifolds for F-theory on K3 Surfaces
2025-09-15 15:00 - 16:00 | CMSA Room G10, CMSA, 20 Garden Street, Cambridge, MA, 02138, United States
Quantum Field Theory and Physical Mathematics Seminar
Speaker: Chuck Doran (Alberta/CMSA)
Title: Orientifolds for F-theory on K3 Surfaces
Abstract: 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.

Topological Manifolds – The First 100 Years
2025-09-15 16:30 - 17:30 | CMSA Room G10, CMSA, 20 Garden Street, Cambridge, MA, 02138, United States
Colloquium
Speaker: Michael Freedman (Harvard CMSA and Logical Intelligence)
Title: Topological Manifolds – The First 100 Years
Abstract: 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.

Moduli spaces of 4d N=2 quantum field theories
2025-09-18 16:00 - 17:00 | CMSA Room G10, CMSA, 20 Garden Street, Cambridge, MA, 02138, United States
Differential Geometry and Physics Seminar
Speaker: Robert Moscrop, CMSA
Title: Moduli spaces of 4d N=2 quantum field theories
Abstract: 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.

Top-Down Perspectives on Symmetry Theories
2025-09-19 12:00 - 13:00 | Common Room, CMSA, 20 Garden Street, Cambridge, MA, 02138, United States
Member Seminar
Speaker: Max Hubner
Title: Top-Down Perspectives on Symmetry Theories
Abstract: I will review the construction and utility of symmetry theories for string constructed quantum field theories. Symmetry theories are extra-dimensional auxiliary theories separating aspects of a quantum field theory’s symmetries from many of its more messy features. For QFTs with extra-dimensional string constructions the symmetry theory derives directly from the extra-dimensional geometry. This perspective allows for the study of symmetries of famously string engineered systems, such as SCFTs in 5D and 6D, which we will discuss on an example by example basis.

Non-Supersymmetric Orbifolds, Quivers and Chen-Ruan Orbifold Cohomology
2025-09-22 15:00 - 16:00 | CMSA Room G10, CMSA, 20 Garden Street, Cambridge, MA, 02138, United States
Quantum Field Theory and Physical Mathematics Seminar
Speaker: Max Hübner (Uppsala & CMSA)
Title: Non-Supersymmetric Orbifolds, Quivers and Chen-Ruan Orbifold Cohomology
Abstract: 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.

Turbulent Mixing and Antagonistic Microorganisms
2025-09-22 16:30 - 17:30 | CMSA Room G10, CMSA, 20 Garden Street, Cambridge, MA, 02138, United States
Colloquium
Speaker: David Nelson, Harvard
Title: Turbulent Mixing and Antagonistic Microorganisms
Abstract: 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.

Degeneration of Calabi-Yau 3-folds and 3-forms
2025-09-25 16:00 - 17:00 | CMSA Room G10, CMSA, 20 Garden Street, Cambridge, MA, 02138, United States
Differential Geometry and Physics Seminar
Speaker: Teng Fei, Rutgers
Title: Degeneration of Calabi-Yau 3-folds and 3-forms
Abstract: 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.

Sections of fibrations onto curves in characteristic p>0
2025-09-26 12:00 - 13:00 | Common Room, CMSA, 20 Garden Street, Cambridge, MA, 02138, United States
Member Seminar
Speaker: Iacopo Brivio
Title: Sections of fibrations onto curves in characteristic p>0
Abstract: This talk is based on joint work in progress with Ben Church. Using symplectic geometry, Pieloch showed that every smooth fibration $fcolon Xto mathbb{P}^1$ of complex projective varieties always admits a section. I will explain how this theorem can be recovered using techniques from Hodge theory and the Minimal Model Program. An advantage of this approach is that it allows for a positive characteristic generalization, by replacing the Hodge theoretic input by a crystalline one. I will also give an example showing that Pieloch’s result can fail in characteristic p>0.

Graph integrals on Kahler manifolds
2025-09-29 15:00 - 16:00 | CMSA Room G10, CMSA, 20 Garden Street, Cambridge, MA, 02138, United States
Quantum Field Theory and Physical Mathematics Seminar
Speaker: Minghao Wang, Boston University
Title: Graph integrals on Kahler manifolds
Abstract: 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

Geometry and Quantum Theory Seminar
2025-09-30 16:15 - 18:30 | Science Center 507, 1 Oxford Street, Cambridge, 02138
Geometry and Quantum Theory Seminar
Speaker 1: Max Hubner, CMSA
Title: On Topological Structures in String Theory
Abstract: Geometric engineering constructions in string theory often realize QFTs relative to an extra-dimensional geometry. This perspective parallels the symmetry TFT construction where a QFT is presented relative to its extra-dimensional symmetry quiche. Unsurprisingly, as we will discuss, these constructions are related. Topological features of the extra-dimensional geometry map onto the symmetry TFT. We discuss examples and generalization beyond purely geometric constructions in string theory.
Speaker 2: Bowen Yang, CMSA
Title: Bounded L theory
Abstract: Bounded L-groups arise in the intersection of algebraic L-theory and large-scale geometry, providing a framework for quadratic forms and automorphisms subject to uniform control conditions. These groups play a role in topology and surgery theory, especially in contexts where one needs to measure obstructions not just algebraically but also geometrically, with bounds on propagation or support. In this talk I will give a gentle introduction to the basic definitions, explain how bounded L-groups differ from classical L-groups, and outline an application to quantum many body invariants.

Tropicalized quantum field theory
2025-10-01 14:00 - 15:00 | Virtual
New Technologies in Mathematics Seminar
Speaker: Michael Borinsky, Perimeter Institute
Title: Tropicalized quantum field theory
Abstract: 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.
I 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.

Special Kähler geometry and collapsing
2025-10-02 16:00 - 17:00 | CMSA Room G10, CMSA, 20 Garden Street, Cambridge, MA, 02138, United States
Differential Geometry and Physics Seminar
Speaker: Valentino Tosatti, NYU Courant Institute
Title: Special Kähler geometry and collapsing
Abstract: 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.

Local Donaldson-Scaduto conjecture
2025-10-03 12:00 - 13:00 | Common Room, CMSA, 20 Garden Street, Cambridge, MA, 02138, United States
Member Seminar
Speaker: Saman Habibi Esfahani
Title: Local Donaldson-Scaduto conjecture
Abstract: 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.

Non-perturbative aspects of self-dual gauge theory
2025-10-06 15:00 - 16:00 | Virtual
Quantum Field Theory and Physical Mathematics Seminar
Speaker: Kevin Costello (Perimeter Institute)

Title: Non-perturbative aspects of self-dual gauge theory

Abstract: 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.

Geometry of dimer models
2025-10-06 16:30 - 17:30 | CMSA Room G10, CMSA, 20 Garden Street, Cambridge, MA, 02138, United States
Colloquium
Speaker: Alexei Borodin, MIT
Title: Geometry of dimer models
Abstract: 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.

A Classifying Space for Phases of Matrix Product States
2025-10-07 16:15 - 18:30 | Science Center 507, 1 Oxford Street, Cambridge, 02138
Geometry and Quantum Theory Seminar
Speakers: Daniel Spiegel, Harvard Math
Title: A Classifying Space for Phases of Matrix Product States
Abstract: 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.
Daniel Spiegel will speak for 60 minutes.
Sunghyuk Park (CMSA) will also speak for 15 minutes

Understanding Optimization in Deep Learning with Central Flows
2025-10-08 14:00 - 15:00 | Hybrid – G10
New Technologies in Mathematics Seminar
Speaker: Alex Damian, Harvard
Title: Understanding Optimization in Deep Learning with Central Flows
Abstract: 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.

Profinite tensor powers
2025-10-09 14:00 - 15:00 | CMSA Room G10, CMSA, 20 Garden Street, Cambridge, MA, 02138, United States
Algebra Seminar
Speaker: David Treumann (Boston College)
Title: Profinite tensor powers
Abstract: 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.

Symmetries and Moduli Spaces: Baby Steps beyond Calabi-Yau
2025-10-09 16:00 - 17:00 | CMSA Room G10, CMSA, 20 Garden Street, Cambridge, MA, 02138, United States
Differential Geometry and Physics Seminar
Speaker: Xingyang Yu, Virginia Tech
Title: Symmetries and Moduli Spaces: Baby Steps beyond Calabi-Yau
Abstract: 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.

The Rozansky-Witten field theory in the functorial TQFT formalism
2025-10-10 12:00 - 13:00 | Common Room, CMSA, 20 Garden Street, Cambridge, MA, 02138, United States
Member Seminar
Speaker: Lorenzo Riva
Title: The Rozansky-Witten field theory in the functorial TQFT formalism
Abstract: 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”).

Geometry and Quantum Theory Seminar
2025-10-14 16:15 - 18:30 | Science Center 507, 1 Oxford Street, Cambridge, 02138
Geometry and Quantum Theory Seminar
Speaker: Dylan Galt, Harvard
(60 minute talk)
Title: What is a “nonlinear” near-symplectic form?
Abstract: 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.

Speaker: Keyou Zeng, CMSA
(30 minute talk)
Title: Cohomology of configuration space of points
Abstract: 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.
