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DTSTART;TZID=America/New_York:20260424T120000
DTEND;TZID=America/New_York:20260424T130000
DTSTAMP:20260501T050621
CREATED:20260212T190445Z
LAST-MODIFIED:20260420T151342Z
UID:10003907-1777032000-1777035600@cmsa.fas.harvard.edu
SUMMARY:The Intermingling of Symmetry and Parametrization in Matrix Product States
DESCRIPTION:Member Seminar \nSpeaker: Daniel Spiegel \nTitle: The Intermingling of Symmetry and Parametrization in Matrix Product States \nAbstract: In the study of quantum spin systems\, it is by now well-known that interesting phases of quantum matter can arise from gapped ground states when the system is invariant under a symmetry group G or when the system varies continuously with a parameter in a topological space X. In these cases\, phases are characterized by indices taking values in group cohomology of G or the cohomology of X\, respectively. The situation where one has both a symmetry and a parametrization is much less studied but can lead to interesting phases even when both the aforementioned indices are trivial. In this talk\, I will discuss work in progress on a simple construction for general index for symmetry protected parametrized systems of matrix product states and will show some illustrative examples.
URL:https://cmsa.fas.harvard.edu/event/member-seminar-42426/
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-4.24.26-scaled.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20260417T120000
DTEND;TZID=America/New_York:20260417T130000
DTSTAMP:20260501T050621
CREATED:20260212T190403Z
LAST-MODIFIED:20260409T160741Z
UID:10003906-1776427200-1776430800@cmsa.fas.harvard.edu
SUMMARY:Higgs and Coulomb branches: Geometry and Representation Theory
DESCRIPTION:Member Seminar \nSpeaker: Vasily Krylov \nTitle: Higgs and Coulomb branches: Geometry and Representation Theory \nAbstract: Higgs and Coulomb branches of quiver gauge theories form two important families of Poisson varieties that are expected to be exchanged under so-called 3D mirror symmetry. Quantized Coulomb branches are associative algebras deforming the algebras of functions on Coulomb branches. They are closely related to many important representation-theoretic structures\, such as Yangians\, quantum groups\, and Hecke algebras. In this talk\, I will discuss how 3D mirror symmetry\, together with other insights motivated by physics\, yields very explicit answers to purely representation-theoretic questions about representations of some of these quantum groups. Talk is based on joint works with Dinkins\, Karpov\, Klyuev\, and Lance.
URL:https://cmsa.fas.harvard.edu/event/member-seminar-41726/
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-4.17.26.docx.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20260410T120000
DTEND;TZID=America/New_York:20260410T130000
DTSTAMP:20260501T050621
CREATED:20260212T190254Z
LAST-MODIFIED:20260330T200409Z
UID:10003905-1775822400-1775826000@cmsa.fas.harvard.edu
SUMMARY:Quantum topology from dynamics
DESCRIPTION:Member Seminar \nSpeaker: Sunghyuk Park\, CMSA \nTitle: Quantum topology from dynamics \nAbstract: Dynamics studies the long-term behavior of systems that evolve over time\, such as the famous Lorenz system.\nQuantum topology\, by contrast\, studies knots and low-dimensional manifolds through invariants that are usually constructed using representation-theoretic tools. In this talk\, I will explain how quantum invariants of knots and 3-manifolds can be recovered from the dynamics of certain three-dimensional flows. Time permitting\, I will also explain how this new bridge arises from ideas in topological string theory. \n 
URL:https://cmsa.fas.harvard.edu/event/member-seminar-41026/
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-4.10.26-scaled.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20260403T120000
DTEND;TZID=America/New_York:20260403T130000
DTSTAMP:20260501T050621
CREATED:20260212T190229Z
LAST-MODIFIED:20260331T190743Z
UID:10003904-1775217600-1775221200@cmsa.fas.harvard.edu
SUMMARY:Failures of Holographic Emergence
DESCRIPTION:Member Seminar \nSpeaker: Elliott Gesteau\, CMSA \nTitle: Failures of Holographic Emergence \nAbstract: Recent developments have taught us that some semiclassical spacetimes\, in particular those containing closed universe components\, cannot emerge from a holographic correspondence. In this talk\, I will explain how one can get to this conclusion by using either quantum information theory or properties of the large N limit of AdS/CFT\, and propose a criterion for detecting failures of spacetime emergence. \n 
URL:https://cmsa.fas.harvard.edu/event/member-seminar-4326/
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-4.3.26.docx.1.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20260227T120000
DTEND;TZID=America/New_York:20260227T130000
DTSTAMP:20260501T050621
CREATED:20251223T204714Z
LAST-MODIFIED:20260223T194128Z
UID:10003867-1772193600-1772197200@cmsa.fas.harvard.edu
SUMMARY:Gauge theory\, from low dimensions to higher dimensions and back
DESCRIPTION:Member Seminar \nSpeaker: Saman Habibi Esfahani\, CMSA \nTitle: Gauge theory\, from low dimensions to higher dimensions and back \nAbstract: Almost thirty years ago\, Donaldson and Thomas proposed extending powerful ideas from gauge theory\, which had transformed the study of three- and four-dimensional manifolds\, to higher dimensions\, with the goal of defining new invariants of special holonomy manifolds. In this talk\, I will outline the main ideas behind this program\, mention some recent progress\, and describe the key obstacles that remain\, most notably non-compactness phenomena that make the analysis difficult.
URL:https://cmsa.fas.harvard.edu/event/member-seminar-22726/
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-2.27.26-scaled.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20260220T120000
DTEND;TZID=America/New_York:20260220T130000
DTSTAMP:20260501T050621
CREATED:20251223T204654Z
LAST-MODIFIED:20260217T154410Z
UID:10003866-1771588800-1771592400@cmsa.fas.harvard.edu
SUMMARY:Theory of Task-Adapted Dynamics in Large Recurrent Neural Networks
DESCRIPTION:Member Seminar \nSpeaker: Blake Bordelon\, CMSA \nTitle: Theory of Task-Adapted Dynamics in Large Recurrent Neural Networks \nAbstract: Recurrent neural networks (RNNs) encode expressive and flexible dynamical systems which can adapt to perform tasks by modifying the internal connections between neurons. In this work we analyze the structure of the dynamical systems encoded in RNNs after being trained to perform a learning task. We derive a mean field theory of the dynamics of RNNs before and after learning. Our theory predicts heterogeneous activity and tuning of single neurons\, but precise\, deterministic predictions for population level autocorrelation and outputs of the network. Further\, our theory enables us to interpolate between different operating regimes for RNN learning including (1) reservoir computing regime where internal adaptations do not adapt to data as the model outputs fit the provided data and (2) a feature-learning where the internal dynamics of the network change significantly due to task learning and reflect temporal properties of the learning task. These different regimes exhibit different levels of chaotic activity\, oscillatory behaviors\, and length generalization properties as feature learning enables maintenance of temporal patterns over longer periods than the supervision period. We apply this theory to a biologically grounded motor learning task where a recurrent population is trained to output EMG signals from macaque motor units during an oriented reaching task. We find that many levels of feature-learning strength give rise to high quality fits of the EMG data\, resulting in a family of solutions that are compatible with the neural data. Based on work with David Clark\, Jacob Zavatone Veth\, and Cengiz Pehlevan.
URL:https://cmsa.fas.harvard.edu/event/member-seminar-22026/
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-2.20.26.docx-scaled.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20260213T120000
DTEND;TZID=America/New_York:20260213T130000
DTSTAMP:20260501T050621
CREATED:20251223T204554Z
LAST-MODIFIED:20260210T152049Z
UID:10003865-1770984000-1770987600@cmsa.fas.harvard.edu
SUMMARY:A leisurely stroll through the theory of adjunctions
DESCRIPTION:Member Seminar \nSpeaker: Lorenzo Riva\, Harvard CMSA \nTitle: A leisurely stroll through the theory of adjunctions \nAbstract: Adjoint functors (and\, more generally\, adjunctions in a 2-category) are ubiquitous in algebra and topology. In this talk I will give an overview of the basics of adjunctions\, with the ultimate goal being understanding the statement of the cobordism hypothesis. Time permitting\, I will talk about some recent work on a combinatorial construction yielding free adjunctions. \n 
URL:https://cmsa.fas.harvard.edu/event/member-seminar-21326/
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-2.13.26.docx-scaled.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20260206T120000
DTEND;TZID=America/New_York:20260206T130000
DTSTAMP:20260501T050621
CREATED:20250203T163329Z
LAST-MODIFIED:20260204T153228Z
UID:10003712-1770379200-1770382800@cmsa.fas.harvard.edu
SUMMARY:Lie algebra cohomology and Seiberg-Witten theory
DESCRIPTION:Member Seminar \nSpeaker: Ahsan Khan\, Harvard CMSA \nTitle: Lie algebra cohomology and Seiberg-Witten theory \nAbstract: I will discuss how a certain (relative) Lie algebra cochain complex categorifies the Schur index of N=2 supersymmetric gauge theory. For the special case of Seiberg-Witten theory I will provide a conjectured description of this cohomology.
URL:https://cmsa.fas.harvard.edu/event/member-seminar-2626/
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-2.6.26.docx-scaled.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20260130T120000
DTEND;TZID=America/New_York:20260130T130000
DTSTAMP:20260501T050621
CREATED:20251014T142709Z
LAST-MODIFIED:20260128T171404Z
UID:10003811-1769774400-1769778000@cmsa.fas.harvard.edu
SUMMARY:Some results about saturation
DESCRIPTION:Member Seminar \nSpeaker: Stephen Landsittel \nTitle: Some results about saturation \nAbstract: Given a local ring R we can ask when saturation of ideals in R commutes with other operations on ideals (such as extension to a ring containing R). We show that the condition that extension of ideals along a ring map R \to S commutes with saturation controls inherent properties of the rings R & S\, such as Cohen-Macaulayness and unramifiedness.
URL:https://cmsa.fas.harvard.edu/event/member-seminar-13026/
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-1.30.26.docx-1-scaled.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20251205T120000
DTEND;TZID=America/New_York:20251205T130000
DTSTAMP:20260501T050621
CREATED:20250827T142953Z
LAST-MODIFIED:20251202T160532Z
UID:10003772-1764936000-1764939600@cmsa.fas.harvard.edu
SUMMARY:A combinatorial formula for interpolation Macdonald polynomials
DESCRIPTION:Member Seminar \nSpeaker: Houcine Ben Dali\, Harvard CMSA \nTitle: A combinatorial formula for interpolation Macdonald polynomials \nAbstract: In 1996\, Knop and Sahi introduced a remarkable family of inhomogeneous symmetric polynomials\, defined via vanishing conditions\, whose top homogeneous parts are exactly the Macdonald polynomials. Like the Macdonald polynomials\, these interpolation Macdonald polynomials are closely connected to the Hecke algebra\, and admit nonsymmetric versions\, which generalize the nonsymmetric Macdonald polynomials. I will present a combinatorial formula for interpolation Macdonald polynomials in terms of signed multiline queues. This formula generalizes the combinatorial formula for Macdonald polynomials in terms of multiline queues given by Corteel–Mandelshtam–Williams. This is based on a joint work with Lauren Williams.
URL:https://cmsa.fas.harvard.edu/event/member-seminar-12525/
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-12.5.25.docx-scaled.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20251121T120000
DTEND;TZID=America/New_York:20251121T130000
DTSTAMP:20260501T050621
CREATED:20250827T142348Z
LAST-MODIFIED:20251118T150222Z
UID:10003771-1763726400-1763730000@cmsa.fas.harvard.edu
SUMMARY:Optimal learning protocols via statistical physics and control theory
DESCRIPTION:Member Seminar \nSpeaker: Francesco Mori\, CMSA \nTitle: Optimal learning protocols via statistical physics and control theory \nAbstract: Behind the impressive performance of modern machine learning lies a toolkit of training tricks\, from tuning learning rates to curating training data. These heuristics are powerful but hard to interpret and possibly suboptimal\, leaving open the challenge of finding general principles for protocol design. In this talk\, I will present a framework that combines tools from statistical physics and control theory to identify optimal training strategies in simple yet insightful neural network models. In the high-dimensional limit\, the training dynamics can be reduced to closed-form ordinary differential equations for a small set of order parameters that track learning. This reduction allows us to pose the design of training protocols as an optimal control problem directly on the order-parameter dynamics\, with the objective of minimizing the generalization error. This formulation encompasses a variety of learning scenarios and yields principled training strategies that clarify\, and in some cases improve upon\, standard heuristic practices.
URL:https://cmsa.fas.harvard.edu/event/member-seminar-112125/
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-11.21.25.docx-scaled.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20251107T120000
DTEND;TZID=America/New_York:20251107T130000
DTSTAMP:20260501T050621
CREATED:20250827T141526Z
LAST-MODIFIED:20251103T161856Z
UID:10003769-1762516800-1762520400@cmsa.fas.harvard.edu
SUMMARY:Classification of 2D Stabilizer States
DESCRIPTION:Member Seminar \nSpeaker: Bowen Yang \nTitle: Classification of 2D Stabilizer States \nAbstract: I will explain how translation-invariant two-dimensional stabilizer states are completely classified by finite abelian groups with nondegenerate quadratic forms—that is\, by abelian anyon theories. The proof uses the algebraic structure of stabilizer codes as modules over Laurent polynomial rings\, revealing how their physical features reflect in this module-theoretic framework. arXiv:2509.10418
URL:https://cmsa.fas.harvard.edu/event/member-seminar-11725/
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-11.7.25-scaled.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20251031T120000
DTEND;TZID=America/New_York:20251031T130000
DTSTAMP:20260501T050621
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
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20251024T120000
DTEND;TZID=America/New_York:20251024T130000
DTSTAMP:20260501T050621
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:20251017T120000
DTEND;TZID=America/New_York:20251017T130000
DTSTAMP:20260501T050621
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:20251010T120000
DTEND;TZID=America/New_York:20251010T130000
DTSTAMP:20260501T050621
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:20251003T120000
DTEND;TZID=America/New_York:20251003T130000
DTSTAMP:20260501T050621
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:20250926T120000
DTEND;TZID=America/New_York:20250926T130000
DTSTAMP:20260501T050621
CREATED:20250826T193028Z
LAST-MODIFIED:20250918T172135Z
UID:10003763-1758888000-1758891600@cmsa.fas.harvard.edu
SUMMARY:Sections of fibrations onto curves in characteristic p>0
DESCRIPTION:Member Seminar \nSpeaker: Iacopo Brivio \nTitle: Sections of fibrations onto curves in characteristic p>0 \nAbstract: This talk is based on joint work in progress with Ben Church. Using symplectic geometry\, Pieloch showed that every smooth fibration $f\colon X\to \mathbb{P}^1$ of complex projective varieties always admits a section. I will explain how this theorem can be recovered using techniques from Hodge theory and the Minimal Model Program. An advantage of this approach is that it allows for a positive characteristic generalization\, by replacing the Hodge theoretic input by a crystalline one. I will also give an example showing that Pieloch’s result can fail in characteristic p>0.
URL:https://cmsa.fas.harvard.edu/event/member-seminar-92625/
LOCATION:Common Room\, CMSA\, 20 Garden Street\, Cambridge\, MA\, 02138\, United States
CATEGORIES:Member Seminar
ATTACH;FMTTYPE=image/png:https://cmsa.fas.harvard.edu/media/CMSA-Member-Seminar-9.26.25-1.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20250919T120000
DTEND;TZID=America/New_York:20250919T130000
DTSTAMP:20260501T050621
CREATED:20241211T195345Z
LAST-MODIFIED:20250918T184123Z
UID:10003648-1758283200-1758286800@cmsa.fas.harvard.edu
SUMMARY:Top-Down Perspectives on Symmetry Theories
DESCRIPTION:Member Seminar \nSpeaker: Max Hubner \nTitle: Top-Down Perspectives on Symmetry Theories \nAbstract: I will review the construction and utility of symmetry theories for string constructed quantum field theories. Symmetry theories are extra-dimensional auxiliary theories separating aspects of a quantum field theory’s symmetries from many of its more messy features. For QFTs with extra-dimensional string constructions the symmetry theory derives directly from the extra-dimensional geometry. This perspective allows for the study of symmetries of famously string engineered systems\, such as SCFTs in 5D and 6D\, which we will discuss on an example by example basis.
URL:https://cmsa.fas.harvard.edu/event/member-seminar-91925/
LOCATION:Common Room\, CMSA\, 20 Garden Street\, Cambridge\, MA\, 02138\, United States
CATEGORIES:Member Seminar
ATTACH;FMTTYPE=image/png:https://cmsa.fas.harvard.edu/media/CMSA-Member-Seminar-9.19.25-scaled.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20250516T120000
DTEND;TZID=America/New_York:20250516T130000
DTSTAMP:20260501T050621
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:20250509T120000
DTEND;TZID=America/New_York:20250509T130000
DTSTAMP:20260501T050621
CREATED:20241211T195446Z
LAST-MODIFIED:20250506T153832Z
UID:10003649-1746792000-1746795600@cmsa.fas.harvard.edu
SUMMARY:Asset pricing with heterogeneous agents
DESCRIPTION:Member Seminar \nSpeaker: Sergiy Verstyuk\, Harvard CMSA \nTitle: Asset pricing with heterogeneous agents \nAbstract: This talk will introduce the basics of continuous-time finance\, discuss important existing theories and models\, as well as present some new asset pricing results in a setting with many heterogeneous investors. (Joint work with Puskar Mondal.) \n 
URL:https://cmsa.fas.harvard.edu/event/member-seminar-5925/
LOCATION:CMSA Room G10\, CMSA\, 20 Garden Street\, Cambridge\, MA\, 02138\, United States
CATEGORIES:Member Seminar
ATTACH;FMTTYPE=image/png:https://cmsa.fas.harvard.edu/media/CMSA-Member-Seminar-5.9.25.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20250502T120000
DTEND;TZID=America/New_York:20250502T130000
DTSTAMP:20260501T050621
CREATED:20241211T195435Z
LAST-MODIFIED:20250428T151202Z
UID:10003650-1746187200-1746190800@cmsa.fas.harvard.edu
SUMMARY:Incentives for data sharing in federated learning
DESCRIPTION:Member Seminar \nSpeaker: Han Shao\, Harvard CMSA \nTitle: Incentives for data sharing in federated learning \nAbstract: Federated learning has recently emerged as a powerful approach for enabling collaboration across large populations of learning agents. However\, agents may have incentives to defect from the collaboration—that is\, to withdraw or contribute less data than expected—due to the costs of data curation and privacy concerns. This raises several key questions: What happens when agents defect\, and how can we prevent such defections? \n 
URL:https://cmsa.fas.harvard.edu/event/member-seminar-5225/
LOCATION:CMSA Room G10\, CMSA\, 20 Garden Street\, Cambridge\, MA\, 02138\, United States
CATEGORIES:Member Seminar
ATTACH;FMTTYPE=image/png:https://cmsa.fas.harvard.edu/media/CMSA-Member-Seminar-5.2.25.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20250418T120000
DTEND;TZID=America/New_York:20250418T130000
DTSTAMP:20260501T050621
CREATED:20241211T195316Z
LAST-MODIFIED:20250218T160819Z
UID:10003647-1744977600-1744981200@cmsa.fas.harvard.edu
SUMMARY:Member Seminar
DESCRIPTION:Member Seminar \nSpeaker: Han Shao \n 
URL:https://cmsa.fas.harvard.edu/event/member-seminar-41825/
LOCATION:CMSA Room G10\, CMSA\, 20 Garden Street\, Cambridge\, MA\, 02138\, United States
CATEGORIES:Member Seminar
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20250411T120000
DTEND;TZID=America/New_York:20250411T130000
DTSTAMP:20260501T050621
CREATED:20241211T195247Z
LAST-MODIFIED:20250407T150951Z
UID:10003646-1744372800-1744376400@cmsa.fas.harvard.edu
SUMMARY:Homological Invariants in Translation-Invariant Pauli Stabilizer Codes
DESCRIPTION:Member Seminar \nSpeaker: Bowen Yang \nTitle: Homological Invariants in Translation-Invariant Pauli Stabilizer Codes \nAbstract: Pauli stabilizer codes serve as foundational models in quantum error correction and the study of exotic quantum phases. In this talk\, we explore the application of homological methods to translationally invariant Pauli stabilizer codes with qudits of varying dimensions. We introduce a series of invariants\, termed charge modules\, and delve into their properties and physical interpretations. A key focus is on codes whose charge modules exhibit zero Krull dimension\, a condition indicative of the mobility of excitations. Notably\, we demonstrate that this condition is universally met in two-dimensional codes with a unique ground state in infinite volume\, extending prior findings beyond the realm of uniform\, prime qudit dimensions. For systems where all excitations are mobile\, we establish the existence of p-dimensional excitations and associated (D−p−1)-form symmetries corresponding to each element of the p-th charge module. Additionally\, we define a braiding pairing between charge modules in complementary degrees.
URL:https://cmsa.fas.harvard.edu/event/member-seminar-41125/
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-4.11.25.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20250404T120000
DTEND;TZID=America/New_York:20250404T130000
DTSTAMP:20260501T050621
CREATED:20241211T195214Z
LAST-MODIFIED:20250328T164025Z
UID:10003645-1743768000-1743771600@cmsa.fas.harvard.edu
SUMMARY:Learning diffusion models in high-dimensions
DESCRIPTION:Member Seminar \nSpeaker: Hugo Cui \nTitle: Learning diffusion models in high-dimensions \nAbstract: We consider the problem of learning a generative model parametrized by a two-layer auto-encoder\, and trained with online stochastic gradient descent\, to sample from a high-dimensional data distribution with an underlying low-dimensional structure. We provide a tight asymptotic characterization of low-dimensional projections of the resulting generated density\, and evidence how mode(l) collapse can arise.  On the other hand\, we discuss how in a case where the architectural bias is suited to the target density\, these simple models can efficiently learn to sample from a binary Gaussian mixture target distribution. \n 
URL:https://cmsa.fas.harvard.edu/event/member-seminar-4425/
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-4.4.25.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20250328T120000
DTEND;TZID=America/New_York:20250328T130000
DTSTAMP:20260501T050621
CREATED:20241211T195142Z
LAST-MODIFIED:20250324T153000Z
UID:10003644-1743163200-1743166800@cmsa.fas.harvard.edu
SUMMARY:The Competition Complexity of Dynamic Pricing
DESCRIPTION:Member Seminar \nSpeaker: Tomer Ezra \nTitle: The Competition Complexity of Dynamic Pricing \nAbstract: One of the most fundamental questions in mechanism design is the tradeoff between simplicity and optimality. A canonical example of this tradeoff is competition complexity in auctions\, which quantifies how many additional bidders are needed for a simple mechanism to (approximately) match the revenue of the optimal mechanism. \nIn this talk\, we analyze the competition complexity of dynamic pricing in the setting of selling a single item. We establish tight asymptotic guarantees for various scenarios\, including when bidder values are i.i.d.\, independent\, or correlated. Our results characterize the performance of different classes of dynamic pricing algorithms and provide insights into their effectiveness under varying market conditions.
URL:https://cmsa.fas.harvard.edu/event/member-seminar-32825/
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-3.28.25.docx-1.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20250307T120000
DTEND;TZID=America/New_York:20250307T130000
DTSTAMP:20260501T050621
CREATED:20241211T192236Z
LAST-MODIFIED:20250303T133212Z
UID:10003642-1741348800-1741352400@cmsa.fas.harvard.edu
SUMMARY:A Tetrahedral Approach to Calabi-Yau Geometry
DESCRIPTION:Member Seminar \nSpeaker: Charles Doran\, CMSA \nTitle: A Tetrahedral Approach to Calabi-Yau Geometry \nAbstract:  We will open with a quick introduction to the what and why of Calabi-Yau geometry.  Following this\, we will consider the problem of deforming tetrahedra while preserving the areas of their faces\, following our noses to discover a beautiful path to elliptic curves\, K3 surfaces\, and beyond.  Time permitting\, we will also discuss motivations and applications across physics.  The talk should be broadly accessible. \n 
URL:https://cmsa.fas.harvard.edu/event/member-seminar-3724/
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-3.7.25.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20250228T120000
DTEND;TZID=America/New_York:20250228T130000
DTSTAMP:20260501T050621
CREATED:20241211T172401Z
LAST-MODIFIED:20250225T155302Z
UID:10003641-1740744000-1740747600@cmsa.fas.harvard.edu
SUMMARY:The Combinatorics of the Amplituhedron – Tiles\, Tilings\, and Cluster Algebras
DESCRIPTION:Member Seminar \nSpeaker: Matteo Parisi \nTitle: The Combinatorics of the Amplituhedron – Tiles\, Tilings\, and Cluster Algebras \nAbstract: The amplituhedron is the image of the positive Grassmannian—the region of the Grassmannian where all Plücker coordinates are nonnegative—under a totally positive linear map. It is a far-reaching generalization of cyclic polytopes and hyperplane arrangements\, and the positive Grassmannian itself. The “volume” of the amplituhedron encodes probabilities of particle interactions in the quantum field theory N=4 super Yang-Mills\, and calculating this volume involves decomposing (or tiling) the amplituhedron into smaller pieces (or tiles) and summing their volumes. This talk will delve into the rich combinatorics of these tiles and tilings\, presenting recent results on some of the central conjectures in this area\, including the magic number\, BCFW tiling\, and cluster adjacency conjectures.
URL:https://cmsa.fas.harvard.edu/event/member-seminar-22825/
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/1740498728693-b34629b4-eb9a-47b2-9782-46abe1568dd025_1.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20250214T120000
DTEND;TZID=America/New_York:20250214T130000
DTSTAMP:20260501T050621
CREATED:20241211T171913Z
LAST-MODIFIED:20250210T162218Z
UID:10003640-1739534400-1739538000@cmsa.fas.harvard.edu
SUMMARY:Jack polynomials and enumeration of non-orientable maps
DESCRIPTION:Member Seminar \nSpeaker: Houcine Ben Dali\, Harvard CMSA \nTitle: Jack polynomials and enumeration of non-orientable maps \nAbstract: A map is a graph embedded on a surface\, which may be orientable or not. The representation theory of the symmetric group can be used to write the generating series of maps on orientable surfaces using Schur symmetric functions. \nSeveral conjectures suggest that Jack polynomials—a one-parameter deformation of Schur functions—are related to the enumeration of non-orientable maps counted with a “non-orientability” weight. In this talk\, I will discuss some of these conjectures and present recent progress in this direction.
URL:https://cmsa.fas.harvard.edu/event/member-seminar-21425/
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-2.14.25-1.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=America/New_York:20250131T120000
DTEND;TZID=America/New_York:20250131T130000
DTSTAMP:20260501T050621
CREATED:20250127T180141Z
LAST-MODIFIED:20250127T180704Z
UID:10003638-1738324800-1738328400@cmsa.fas.harvard.edu
SUMMARY:Smooth projective fibrations over the projective line and their sections
DESCRIPTION:Member Seminar \nSpeaker: Iacopo Brivio \nTitle: Smooth projective fibrations over the projective line and their sections \nAbstract: Suppose $f\colon X\to \mathbf{CP}^1$ is a smooth projective fibration\, is it then true that $f$ has a section? This deceptively simple result was established by Seidel and McDuff using deep methods of symplectic geometry. Alex Pieloch recently generalized this to morphisms with at most one singular fibers and furthermore showed that $X$ uniruled\, that is covered by images of $\mathbf{P}^1$. In my talk I will explain how to recover Pieloch’s result from the Good Minimal Model Conjecture. \n 
URL:https://cmsa.fas.harvard.edu/event/member-seminar-13125/
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-1.31.25.png
END:VEVENT
END:VCALENDAR