During the 2023–24 academic year, the CMSA will be hosting a Colloquium series, organized by Alejandro Poveda and Kai Xu. It will take place from 4:30 – 5:30 pm (Eastern Time) in Room G10, CMSA, 20 Garden Street. All CMSA postdocs/members are required to attend the weekly CMSA Colloquium series as well as the weekly CMSA Members’ Seminars. The schedule will be updated as talks are confirmed.

CMSA COVID-19 Policies



  • December 11, 2023 04:30 PM
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  • December 04, 2023 04:30 PM
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  • November 27, 2023 04:30 PM
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  • November 20, 2023 04:30 PM
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  • November 13, 2023 04:30 PM
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  • November 06, 2023 04:30 PM
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  • October 30, 2023 04:30 PM
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  • October 23, 2023 04:30 PM
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  • October 16, 2023 04:30 PM
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  • October 02, 2023 04:30 PM
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  • September 25, 2023 04:30 PM
Speaker: Sean Cox
Title: Predicting non-continuous functions
Venue: CMSA Room G10

Speaker: Sean Cox, Virginia Commonwealth University Title: Predicting non-continuous functions Abstract: One of the strangest consequences of the Axiom of Choice is the following Hardin-Taylor 2008 result: there is a “predictor” such that for every function $f$ from the reals to the reals—even nowhere continuous $f$—the predictor applied to $f \restriction (-\infty,t)$ correctly predicts $f(t)$ for *almost every* $t \in R$. They asked how robust such a predictor could be, with respect to distortions in the time (input) axis; more precisely, for which subgroups $H$ of Homeo^+(R) do there exist $H$-invariant predictors? Bajpai-Velleman proved an affirmative answer when H=Affine^+(R), and a negative answer when H is (the subgroup generated by) C^\infty(R). They asked about the intermediate region; in particular,…

  • September 20, 2023 12:30 PM
Speaker: Tim Adamo
Title: An invitation to strong-field scattering
Venue: CMSA Room G10

Speaker: Tim Adamo, University of Edinburgh Title: An invitation to strong-field scattering Abstract: Scattering amplitudes in strong background fields provide an arena where perturbative and non-perturbative physics meet, with important applications ranging from laser physics to black holes, but their study is hampered by the cumbersome nature of QFT in the background field formalism. In this talk, I will try to convince you that strong-field scattering amplitudes contain a wealth of physical information which cannot be obtained with standard perturbative techniques, ranging from all-order classical observables to constraints on exact solutions. Furthermore, I will discuss how amplitudes in certain chiral strong fields can be obtained to all-multiplicity twistor and string methods.

  • May 03, 2023 12:30 PM
Speaker: Xin Guo
Title: Generative Adversarial Networks (GANs): An Analytical Perspective
Venue: CMSA Room G10

Speaker: Xin Guo, UC Berkeley Title: Generative Adversarial Networks (GANs): An Analytical Perspective Abstract: Generative models have attracted intense interests recently. In this talk, I will discuss one class of generative models, Generative Adversarial Networks (GANs).  I will first provide a gentle review of the mathematical framework behind GANs. I will then proceed to discuss a few challenges in GANs training from an analytical perspective. I will finally report some recent progress for GANs training in terms of its stability and convergence analysis.  

  • April 26, 2023 12:30 PM
Speaker: Max Metlitski
Title: Boundary behavior at classical and quantum phase transitions
Venue: CMSA Room G10

Speaker: Max Metlitski (MIT) Title: Boundary behavior at classical and quantum phase transitions Abstract: There has been a lot of recent interest in the boundary behavior of materials. This interest is driven in part by the field of topological states of quantum matter, where exotic protected boundary states are ubiquitous. In this talk, I’ll ask: what happens at a boundary of a system, when the bulk goes through a phase transition. While this question was studied in the context of classical statistical mechanics in the 70s and 80s, basic aspects of the boundary phase diagram for the simplest classical phase transitions have been missed until recently. I’ll describe progress in this field, as well as some extensions to quantum phase transitions….

  • April 20, 2023 01:30 PM
Speaker: Julio Parra Martinez
Title: Black hole collider physics
Venue: CMSA Room G10

Speaker: Julio Parra Martinez, Caltech Title: Black hole collider physics Abstract: Despite more than a century since the development of Einstein’s theory, the general relativistic two-body problem remains unsolved. A precise description of its solution is now essential, as it is necessary for understanding the strong-gravity dynamics of compact binaries observed at LIGO/VIRGO/KAGRA and in future gravitational wave observatories. In this talk, I will describe how considering the scattering of black holes and gravitons can shed new light on this problem. I will explain how using modern ideas from collider and particle physics we can calculate scattering observables in classical gravity, and extract the basic ingredients that describe the bound binary dynamics. Such calculations have produced state-of-art predictions…

  • April 12, 2023 12:30 PM
Speaker: James Halverson
Title: Unexpected Uses of Neural Networks: Field Theory and Metric Flows  
Venue: CMSA Room G10

Speaker: James Halverson (Northeastern University)   Title: Unexpected Uses of Neural Networks: Field Theory and Metric Flows Abstract:  We are now quite used to the idea that deep neural networks may be trained in a variety of ways to tackle cutting-edge problems in physics and mathematics, sometimes leading to rigorous results. In this talk, however, I will argue that breakthroughs in deep learning theory are also useful for making progress, focusing on applications to field theory and metric flows. Specifically, I will introduce a neural network approach to field theory with a different statistical origin, that exhibits generalized free field behavior at infinite width and interactions at finite width, and that allows for the study of symmetries via the study of correlation functions…

  • April 03, 2023 11:00 AM
Speaker: Luca Iliesiu
Title: Black hole microstate counting from the gravitational path integral
Venue: CMSA Room G10

Colloquium Speaker: Luca Iliesiu, Stanford Title: Black hole microstate counting from the gravitational path integral Abstract: Reproducing the integer count of black hole micro-states from the gravitational path integral is an important problem in quantum gravity. In the first part of the talk, I will show that, by using supersymmetric localization, the gravitational path integral for 1/16-BPS black holes in supergravity can reproduce the index obtained in the string theory construction of such black holes. A more refined argument then shows that not only the black hole index but also the total number of black hole microstates within an energy window above extremality that is polynomially suppressed in the charges also matches this string theory index. In the second part of the talk, I will…

  • March 29, 2023 12:30 PM
Speaker: Ruth Britto
Title: Scattering amplitudes in quantum field theory
Venue: CMSA Room G10

Speaker: Ruth Britto (Trinity College Dublin) Title: Scattering amplitudes in quantum field theory Abstract: Particle collider experiments require a detailed description of scattering events, traditionally computed through sums of Feynman diagrams. However, it is not practical to evaluate Feynman diagrams directly for all significant scattering processes. Moreover, adding all diagrams reveals many cancellations: scattering amplitudes in theories such as QCD take remarkably simple forms. This simplicity is a clue that the perturbative theory is perhaps best understood without reference to Feynman diagrams. In fact, it has recently become possible to explain some of this simplicity. I will show how to derive many amplitudes efficiently and elegantly, and propose taming the remaining complexity with ideas drawn from combinatorics and…

  • March 22, 2023 12:30 PM
Speaker: Mete Soner
Title: Synchronization in a Kuramoto Mean Field Game
Venue: CMSA Room G10

Speaker: Mete Soner (Princeton University) Title: Synchronization in a Kuramoto Mean Field Game Abstract:  Originally motivated by systems of chemical and biological oscillators, the classical Kuramoto model has found an amazing range of applications from neuroscience to Josephson junctions in superconductors, and has become a  key mathematical model to describe self organization in complex systems. These autonomous oscillators are coupled through a nonlinear interaction term which plays a central role in the long term behavior of the system. While the system is not synchronized when this term is not sufficiently strong, fascinatingly, they exhibit an abrupt transition to a full synchronization above a critical value of the interaction parameter.  We explore this system in the mean field formalism.  We treat the system…

  • March 08, 2023 12:30 PM
Speaker: Ning Su
Title: Conformal symmetry, Optimization algorithms and the Critical Phenomena
Venue: CMSA Room G10

Speaker: Ning Su, University of Pisa Title: Conformal symmetry, Optimization algorithms and the Critical Phenomena Abstract: In the phase diagram of many substances, the critical points have emergent conformal symmetry and are described by conformal field theories. Traditionally, physical quantities near the critical point can be computed by perturbative field theory method, where conformal symmetry is not fully utilized. In this talk, I will explain how conformal symmetry can be used to determine certain physical quantities, without even knowing the fine details of the microscopic structure. To compute the observables precisely, one needs to develop powerful numerical techniques. In the last few years, we have invented many computational tools and algorithms, and predicted critical exponents of Helium-4 superfluid…