CMSA Q&A Seminar: Michael Freedman
2024-10-30 12:00 - 13:00 (America/New_York) | Common Room, CMSA, 20 Garden Street, Cambridge, MA, 02138, United States
CMSA Q&A Seminar
Speaker: Michael Freedman, Harvard CMSA
Topic: Broad perspective on manifolds: all dimensions, all structures, classification and dynamics

Mirror Construction for Nakajima Quiver Varieties
2024-10-31 10:00 - 11:00 | CMSA Room G10, CMSA, 20 Garden Street, Cambridge, MA, 02138, United States
Mathematical Physics and Algebraic Geometry Seminar
Speaker: Ju Tan (Boston University)
Title: Mirror Construction for Nakajima Quiver Varieties
Abstract: Quiver possesses a rich representation theory. On the one hand, it exhibits a deep connection with instantons and coherent sheaves as illuminated by the ADHM construction and the works of many others. On the other hand, quivers also capture the formal deformation space of a Lagrangian submanifold. In this talk, we will discuss these relations more explicitly from the perspective of SYZ mirror symmetry. In particular, we will introduce the notion of framed Lagrangian immersions, the Maurer-Cartan deformation spaces of which are Nakajima quiver varieties/ stacks. Besides, we will realize the ADHM construction as a mirror symmetry phenomenon. This is based on the joint work with Jiawei Hu and Siu-Cheong Lau.

Foundation Seminar
2024-11-04 09:30 - 10:30 | Black Hole Initiative, 20 Garden Street, Cambridge MA, CMSA, 20 Garden Street, Cambridge, MA, 02138, United States
Foundation Seminar (Joint Seminar with BHI)
Location: BHI

Speaker: Christoph Kehle (MIT)

Title: On the cosmic censorship conjectures
Abstract: I will present the modern formulations of the weak and strong cosmic censorship conjectures and discuss some recent developments in the context of gravitational collapse.

The mathematics of evolution
2024-11-04 16:30 - 17:30 | CMSA Room G10, CMSA, 20 Garden Street, Cambridge, MA, 02138, United States
Colloquium
Speaker: Martin Nowak (Harvard)
Title: The mathematics of evolution
Abstract: All living systems are guided by evolutionary dynamics. Evolution is a search process which occurs in populations of reproducing individuals. The three fundamental forces of evolution are mutation, selection and cooperation. I will present basic ideas in the mathematical description of evolutionary dynamics, including quasi-species theory, evolutionary game theory, and evolutionary graph theory. I will discuss specific problems such as origin of life, emergence of complexity, mechanisms of cooperation, evolution of cancer and how to overcome resistance to targeted therapy.

Introduction to Factorization algebras
2024-11-05 16:15 - 18:15 | Science Center Hall E, 1 Oxford Street, Cambridge, MA, 02138, United States
Geometry and Quantum Theory Seminar
Speaker: Dan Freed, Harvard University
Title: Introduction to Factorization algebras

CMSA Q&A Seminar: Michael Douglas
2024-11-06 12:00 - 13:00 | Common Room, CMSA, 20 Garden Street, Cambridge, MA, 02138, United States
CMSA Q&A Seminar
Speaker: Michael Douglas, Harvard CMSA
Topic: What is Argyres-Douglas theory?

Is Behavior Cloning All You Need? Understanding Horizon in Imitation Learning
2024-11-06 14:00 - 15:00 | CMSA Room G10, CMSA, 20 Garden Street, Cambridge, MA, 02138, United States
New Technologies in Mathematics Seminar
Speaker: Dylan Foster, Microsoft Research
Title: Is Behavior Cloning All You Need? Understanding Horizon in Imitation Learning
Abstract: Imitation learning (IL) aims to mimic the behavior of an expert in a sequential decision making task by learning from demonstrations, and has been widely applied to robotics, autonomous driving, and autoregressive language generation. The simplest approach to IL, behavior cloning (BC), is thought to incur sample complexity with unfavorable quadratic dependence on the problem horizon, motivating a variety of different online algorithms that attain improved linear horizon dependence under stronger assumptions on the data and the learner’s access to the expert.In this talk, we revisit the apparent gap between offline and online IL from a learning-theoretic perspective, with a focus on general policy classes up to and including deep neural networks. Through a new analysis of behavior cloning with the logarithmic loss, we will show that it is possible to achieve horizon-independent sample complexity in offline IL whenever (i) the range of the cumulative payoffs is controlled, and (ii) an appropriate notion of supervised learning complexity for the policy class is controlled. When specialized to stationary policies, this implies that the gap between offline and online IL is smaller than previously thought. We will then discuss implications of this result and investigate the extent to which it bears out empirically.
Bio: Dylan Foster is a principal researcher at Microsoft Research, New York. Previously, he was a postdoctoral fellow at MIT, and received his PhD in computer science from Cornell University, advised by Karthik Sridharan. His research focuses on problems at the intersection of machine learning, AI, interactive decision making. He has received several awards for his work, including the best paper award at COLT (2019) and best student paper award at COLT (2018, 2019).

Bounds and Dualities of Type II Little String Theories
2024-11-07 10:00 - 11:00 | CMSA Room G10, CMSA, 20 Garden Street, Cambridge, MA, 02138, United States
Mathematical Physics and Algebraic Geometry Seminar
Speaker: Fabian Ruehle (Northeastern University)
Title: Bounds and Dualities of Type II Little String Theories
Abstract: The goal of this seminar is to introduce Type II Little String Theories (LSTs), which are six-dimensional supersymmetric QFTs. We explore how to geometrically engineer these theories within the context of M-/F-theory (top-down) as well as consistent QFT realizations (bottom-up). After that, we turn to the worldsheet theory of LSTs, which are two-dimensional N=(0,4) SCFTs. Using anomaly inflow and unitarity, we derive strong constraints on the rank of their global symmetry algebras.

Representations of minimal W-algebras: unitarity and modular invariance
2024-11-08 10:00 - 11:30 | Virtual
Quantum Field Theory and Physical Mathematics Seminar
Speaker: Victor Kac (MIT)
Title: Representations of minimal W-algebras: unitarity and modular invariance
Abstract: The minimal W-algebras, obtained by quantum Hamiltonian reduction from affina vertex algebras, form the most interesting class of vertex algebras, which includes all superconformal algebras: Virasoro, Neveu-Scharz, N=2, 3, 4, and big N=4. I will explain a unified classification of their unitary representations, and their character formulas. For N=0, 1, and 2 these vertex algebras are modular invariant (meaning that tr q^L_0-c/24 is a modular function). However for all other minimal W-algebra modular invariance fails, and one needs the “modification” of characters to restore modular invariance. Unfortunately the representation-theoretical or physical meaning of the modification is not known (at least to me).

ADHM spaces and their quantizations
2024-11-08 12:00 - 13:00 | CMSA Room G10, CMSA, 20 Garden Street, Cambridge, MA, 02138, United States
Member Seminar
Speaker: Vasily Krylov, CMSA
Title: ADHM spaces and their quantizations
Abstract: In their paper “Construction of Instantons,” Atiyah, Drinfeld, Hitchin, and Manin introduced an algebraic construction of the moduli space of instantons on R^4, now also known as the “ADHM space.” This is a Poisson complex variety; it has been actively studied by both mathematicians and physicists. In this talk, I will review the ADHM construction, present examples, and discuss various geometric and algebraic properties of ADHM spaces. I will also describe natural quantizations of these Poisson varieties. I will explain a joint result with Etingof, Losev, and Simental, providing explicit formulas for the dimensions and characters of all finite-dimensional representations of these quantizations. Time permitting, I will illustrate some predictions of the 3D mirror symmetry in the example of ADHM spaces, following our joint paper with Shlykov.

pp Waves: Quasinormal Modes & Hidden Symmetries of Black Holes
2024-11-12 11:00 - 12:00 | CMSA Room G10, CMSA, 20 Garden Street, Cambridge, MA, 02138, United States
General Relativity Seminar
Speaker: Ahmed Seta, Harvard University
Title: pp Waves: Quasinormal Modes & Hidden Symmetries of Black Holes
Abstract: The spectrum of quasinormal modes of 4D flat space black holes is not analytically tractable, but there are two asymptotic limits where the QNM spectrum is under control: weak damping and strong damping. In this talk, I will explain how these asymptotic QNMs are controlled by dynamical symmetries of the wave equation in certain kinematic limits. These two asymptotic limits are, in turn, captured by the two classes of bound null geodesics in the black hole geometry: the photon ring and the horizon. I will also discuss the Penrose limit: a scaling limit into the geometry experienced by these geodesics, which results in a plane-wave spacetime where the dynamical symmetries get enhanced into isometries.

Frontier of Formal Theorem Proving with Large Language Models: Insights from the DeepSeek-Prover Series
2024-11-13 10:00 - 23:00 | Virtual
New Technologies in Mathematics Seminar
Speaker: Huajian Xin, DeepSeek
Title: Frontier of Formal Theorem Proving with Large Language Models: Insights from the DeepSeek-Prover Series
Abstract: Recent advances in large language models have markedly influenced mathematical reasoning and automated theorem proving within artificial intelligence. Yet, despite their success in natural language tasks, these models face notable obstacles in formal theorem proving environments such as Lean and Isabelle, where exacting derivations must adhere to strict formal specifications. Even state-of-the-art models encounter difficulty generating accurate and complex formal proofs, revealing the unique blend of mathematical rigor required in this domain. In the DeepSeek-Prover series (V1 and V1.5), we have explored specialized methodologies aimed at addressing these challenges. This talk will delve into three foundational areas: the synthesis of training data through autoformalization, reinforcement learning that utilizes feedback from proof assistants, and test-time optimization using Monte Carlo tree search. I will also provide insights into current model capabilities, persistent challenges, and the future potential of large language models in automated theorem proving.

(Un)likely intersections
2024-11-14 10:00 - 11:00 | CMSA Room G10, CMSA, 20 Garden Street, Cambridge, MA, 02138, United States
Mathematical Physics and Algebraic Geometry Seminar
Speaker: Tom Scanlon, UC Berkeley
Title: (Un)likely intersections

Abstract: The Zilber-Pink conjectures predicts that for an ambient special variety (such as an abelian variety or a Shimura variety), if is an irreducible algebraic subvariety which is not contained a proper special subvariety of (e.g. a proper algebraic subgroup in the abelian variety case or a variety of Hodge type in the case of Shimura varieties), then the union of the unlikely intersections as ranges over the special subvarieties of with is not Zariski dense in . While various instances of this conjecture have been proven, it remains open in most cases of interest. In this lecture, I will describe some of my work with Jonathan Pila in which we prove an effective function field version of this conjecture along with a counterpart to the Zilber-Pink conjecture proven with Sebastian Eterović: after accounting for some geometric obstructions, the likely intersections, i.e. the union of the intersections with special and , are dense in the Euclidean topology in . Our techniques for both results come from o-minimal complex analysis and differential algebra.

Quantum Criticality in Black Hole Scattering
2024-11-15 12:00 - 13:00 | CMSA Room G10, CMSA, 20 Garden Street, Cambridge, MA, 02138, United States
Member Seminar
Speaker: Uri Kol
Title: Quantum Criticality in Black Hole Scattering
Abstract: Perturbation theory around rotating black holes captures a few important effects in the physics of gravitational waves emitted from binary mergers. Despite a long and rich history, developing a qualitative understanding of the system remains a challenging problem. In this talk I will describe an emergent critical phenomena arising in black hole perturbation theory, which is reminiscent of the structure found in quantum many-body systems. A critical point is identified at zero temperature, giving rise to a wide “quantum” critical region at finite temperatures that is dominated by critical fluctuations. In the critical region, the physics is exclusively described by a set of critical exponents, therefore leading to robust predictions.

Freedman CMSA Seminar
2024-11-15 14:30 - 17:30 | Virtual
Freedman CMSA Seminar
*Note: via Zoom only*

2:00-3:30 pm ET
Speaker: Michael Freedman, Harvard CMSA
Title: Some questions and theorems about closed 3 manifolds embedded in S^4
Abstract: Much is unknown about smooth embeddings of 3-manifolds in S^4; the Schoenflies problem (Is there only one smoothly embedded 3-sphere in S^4 up to isotopy?) is the best-known example. There has long been a hope that 3-manifold reasoning applied to level-sets will be helpful. I’ll mention some successes and failures of this method and revisit a classical theorem of Hantzsche in this light. (Hantzsche: If a 3-manifold embeds in S^4 its linking form is hyperbolic.)

3:30-4:00 pm ET
Break/Discussion

4:00-5:30 pm ET
Speaker: Slava Krushkal, University of Virginia
Title: A higher order torsion linking form for 3-manifolds
Abstract: This talk is based on a joint work with Mike Freedman defining a triple linking form for rational homology spheres, assuming that the classical torsion linking pairing of three classes pairwise vanishes. I will discuss its vanishing for 3-manifolds in S^4, and its relation to the Matsumoto triple intersection form on 4-manifolds.

Emergent Non-Invertible Symmetries —The Adjoint QCD Example
2024-11-18 14:00 - 15:00 | CMSA Room G10, CMSA, 20 Garden Street, Cambridge, MA, 02138, United States
Quantum Field Theory and Physical Mathematics Seminar
Speaker: Shani Nadir Meynet (Uppsala)
Title: Emergent Non-Invertible Symmetries — The Adjoint QCD Example
Abstract: After reviewing some general properties of generalized symmetries and the renormalization group (RG) flow for quantum field theories (QFT), I’ll describe how the recently discovered non-invertible symmetries can be used to study theories at strong coupling. I’ll illustrate these facts using (3+1)-dimensional adjoint QCD with two flavors as an example. This theory can be obtained by mass deforming a pure N=2 super Yang-Mills theory. Relying on supersymmetric results, dynamical abelianization and monopole condensation, we are able to get to the description of an infrared (IR) phase as an abelian theory flowing to a CP1 sigma model. In this scenario, the IR phase has an emergent non-invertible symmetry, which is matched with the non-invertible symmetry of the IR CP1 phase. This result illustrates how an emergent non-invertible symmetry can be used to provide a bridge connecting gauge theories at strong coupling and their IR via dynamical abelianization.

The Einstein-Euler system with a physical vacuum boundary in spherical symmetry
2024-11-19 11:00 - 12:00 | CMSA Room G10, CMSA, 20 Garden Street, Cambridge, MA, 02138, United States
General Relativity Seminar
Speaker: Marcelo Disconzi, Vanderbilt University
Title: The Einstein-Euler system with a physical vacuum boundary in spherical symmetry
Abstract: We establish local well-posedness for the Einstein-Euler system with a physical vacuum boundary in spherical symmetry. Our proof relies on a new way of thinking about Einstein’s equations in spherical symmetry that is well-adapted to the fluid’s characteristics on the free boundary. We also exploit the Einstein constraint equations in spherical symmetry in a new way, as a tool to understand the evolution problem. This is joint work with Jared Speck.

Factorization algebras in TQFT
2024-11-19 18:00 - 19:00 | Science Center 507, 1 Oxford Street, Cambridge, 02138
Geometry and Quantum Theory Seminar
Speakers: Mayuko Yamashita, Kyoto University
Title: Factorization algebras in TQFT
Abstract: This is the first in the series of our working seminars on factorization algebras/homologies. This talk focuses on locally constant factorization algebras, which correspond to Topological QFTs. I first explain they are equivalent to algebras over E_n operads and their variants. Then I define the factorization homology and discuss basic properties and examples. If time allows, I also mention the connection with the cobordism hypothesis.

Thinking Like Transformers - A Practical Session
2024-11-20 10:00 - 23:00 | Virtual
New Technologies in Mathematics Seminar
Speaker: Gail Weiss, EPFL
Title: Thinking Like Transformers – A Practical Session
Abstract: With the help of the RASP programming language, we can better imagine how transformers—the powerful attention based sequence processing architecture—solve certain tasks. Some tasks, such as simply repeating or reversing an input sequence, have reasonably straightforward solutions, but many others are more difficult. To unlock a fuller intuition of what can and cannot be achieved with transformers, we must understand not just the RASP operations but also how to use them effectively.
In this session, I would like to discuss some useful tricks with you in more detail. How is the powerful selector_width operation yielded from the true RASP operations? How can a fixed-depth RASP program perform arbitrary length long-addition, despite the equally large number of potential carry operations such a computation entails? How might a transformer perform in-context reasoning? And are any of these solutions reasonable, i.e., realisable in practice? I will begin with a brief introduction of the base RASP operations to ground our discussion, and then walk us through several interesting task solutions. Following this, and armed with this deeper intuition of how transformers solve several tasks, we will conclude with a discussion of what this implies for how knowledge and computations must spread out in transformer layers and embeddings in practice.

CMSA Q&A Seminar: Anurag Anshu
2024-11-20 12:00 - 13:00 | Common Room, CMSA, 20 Garden Street, Cambridge, MA, 02138, United States
CMSA Q&A Seminar
Speaker: Anurag Anshu, Harvard University
Topic: What is quantum complexity theory?

A new construction of c = 1 conformal blocks
2024-11-20 15:00 - 16:00 | CMSA Room G10, CMSA, 20 Garden Street, Cambridge, MA, 02138, United States
Mathematical Physics and Algebraic Geometry Seminar
Speaker: Qianyu Hao, University of Geneva
Title: A new construction of c = 1 conformal blocks

Abstract: The Virasoro conformal blocks are very interesting since they have many connections to other areas of math and physics. For example, when c = 1, they are related to tau functions of Painlevé equations. I will first explain what Virasoro conformal blocks are. Then I will describe a new way to construct Virasoro blocks at c = 1 on C by using the “abelian” Heisenberg conformal blocks on a branched double cover of C. The main new idea in our work is to use a spectral network. It is closely related to the idea of nonabelianization of the flat connections in the work of Gaiotto-Moore-Neitzke and Neitzke-Hollands. This nonabelianization construction enables us to compute the harder-to-get Virasoro blocks using the simpler abelian objects. This is based on a joint work with Andrew Neitzke.

Perturbative Factorization Algebras
2024-11-20 16:30 - 17:30 | Science Center Hall E, 1 Oxford Street, Cambridge, MA, 02138, United States
Geometry and Quantum Theory Seminar
Speaker: Ahsan Khan

Title: Perturbative Factorization Algebras

Abstract: In physics the starting point in studying a QFT is to write down an appropriate action functional. My talk will aim to sketch how this connects with the framework of factorization algebras.

CMSA/Tsinghua Math-Science Literature Lecture: Bjorn Poonen, MIT
2024-11-21 09:00 - 10:30 | CMSA Room G10, CMSA, 20 Garden Street, Cambridge, MA, 02138, United States
CMSA/Tsinghua Math-Science Literature Lecture
Date: November 21, 2024
Time: 9:00 – 10:30 am ET
Location: CMSA G10, 20 Garden Street, Cambridge MA & via Zoom
Speaker: Bjorn Poonen, MIT
Title: Ranks of elliptic curves
Abstract: Elliptic curves are simplest varieties whose rational points are not fully understood, and they are the simplest projective varieties with a nontrivial group structure. In 1922 Mordell proved that the group of rational points on an elliptic curve is finitely generated. We will survey what is known and what is believed about this group.

Beginning in Spring 2020, the CMSA began hosting a lecture series on literature in the mathematical sciences, with a focus on significant developments in mathematics that have influenced the discipline, and the lifetime accomplishments of significant scholars.

Skein valued curve counts for the topological vertex and knot conormals
2024-11-21 10:30 - 11:30 | CMSA Room G10, CMSA, 20 Garden Street, Cambridge, MA, 02138, United States
Mathematical Physics and Algebraic Geometry Seminar
Speaker: Tobias Ekholm, Uppsala University
Title: Skein valued curve counts for the topological vertex and knot conormals
Abstract: Combining the invariance of holomorphic curve counts in the skein module with a study of holomorphic curves at infinity of the vertex we find three simple skein operator polynomials that annihilates the (skein valued) topological vertex. We show that these operator polynomials together with natural initial conditions determine the partition function uniquely and then demonstrate that the original Aganagic-Klemm-Marino-Vafa formula for the topological vertex interpreted as a skein valued curve count satisfies the operator polynomials. This is joint work with Longhi and Shende. We end with a general discussion of similar ‘skein D-modules’ for knot conormals.

Identity crises phenomena in the large cardinal hierarchy
2024-11-22 12:00 - 13:00 | CMSA Room G10, CMSA, 20 Garden Street, Cambridge, MA, 02138, United States
Member Seminar
Speaker: Alejandro Poveda
Title: Identity crises phenomena in the large cardinal hierarchy

Abstract: It is well-known that certain mathematical questions cannot be answered on the grounds of the standard foundation of mathematics. Large cardinal axioms constitute a series of postulates about the higher infinite which permit to classify these undecidable problems in a coherent hierarchy way. Specifically, large cardinals together with ZFC (the standard axiomatic of Mathematics) provide a complete classification of all mathematical theories according to the so-called consistency strength. One of the main tenets of modern set theory has been to investigate how the large-cardinal hierarchy is organized across the mathematical universe. To a large extent this hierarchy is nicely disposed and such a disposition is unambiguous (i.e., immune to the independence phenomenon).

In an unexpected turn of events, in the late 70’s Magidor discovered the identity crisis phenomena of the large cardinal hierarchy. Magidor proved that certain strata of the hierarchy are susceptible to be modified via Cohen’s method of forcing. Specifically, he showed that the first strongly compact cardinal can be either the first measurable cardinal or the first supercompact cardinal. It turns out that the first measurable is always much smaller than the first supercompact. These discrepancies on the identity of the first strongly compact cardinal were termed by Magidor the Identity Crisis Phenomenon.

In this talk I plan to provide an introduction to the world of large cardinals keeping an eye on the identity crises phenomena. Time permitting, I’ll present a few recent results answering questions by Magidor and discuss their connection with Woodin’s Ultimate-L Conjecture.

Foundation Seminar
2024-11-25 09:30 - 11:00 | Black Hole Initiative, 20 Garden Street, Cambridge MA, CMSA, 20 Garden Street, Cambridge, MA, 02138, United States
Foundation Seminar (Joint Seminar with BHI)

Title: Searching for Dark Matter in the Sky
Abstract: Astrophysical and cosmological observations have allowed us to measure the abundance of dark matter and have provided important information on its properties. I will discuss past, present and future efforts to map the gravitational footprint of dark matter throughout the cosmos, and what such studies can (and cannot) tell us about dark matter’s fundamental nature. I will also review how even tiny non-gravitational interactions of dark and visible matter could lead to a range of “indirect detection” signals, and outline the status and prospects of searches for such signals, with a focus on the next decade or so.

Mathematical Structures of Scattering Amplitudes
2024-11-25 16:30 - 17:30 | CMSA Room G10, CMSA, 20 Garden Street, Cambridge, MA, 02138, United States
Colloquium
Speaker: Anastasia Volovich, Brown University
Title: Mathematical Structures of Scattering Amplitudes
Abstract: Planar N=4 Yang-Mills scattering amplitudes have been computed to very high loop order. They have many remarkable properties that have sparked interest from mathematicians working on combinatorics, algebraic geometry, and number theory. At the same time, several methods that have been developed for N=4 Yang-Mills can often be applied to more general quantum field theories, including QCD. I will overview some of these exciting developments.

Computability on $mathbb R$ and other continuum-size structures
2024-12-02 16:30 - 17:30 | CMSA Room G10, CMSA, 20 Garden Street, Cambridge, MA, 02138, United States
Colloquium
Speaker: Russell Miller, CUNY
Title: Computability on $mathbb R$ and other continuum-size structures
Abstract: We begin by recalling the notion of a computable function on the real numbers $mathbb R$, developed independently by Gregorczyk and Lacombe over sixty years ago. Using this notion, we note that the real numbers that are themselves computable form a countable subfield of $mathbb R$ with exactly the same first-order properties as $mathbb R$ itself. (Logicians would therefore call it an emph{elementary subfield}.) So, in a first-order sense, everything that happens in $mathbb R$ is already exemplified in this much nicer subfield. However, even when one knows that an existential statement holds for all parameters, it may be impossible (both in $mathbb R$ and in the subfield) to give a computable procedure for producing witnesses. Similar results hold in $mathbb C$.
We will then turn to a different continuum-sized structure: the absolute Galois group $operatorname{Gal}(mathbb Q)$ of the rational numbers. Once again the computable elements of this group form a subgroup, but now it is an open problem whether the group and the subgroup have the same first-order theory, let alone whether this is an elementary subgroup. (If they do have the same theory, this would put nice upper bounds on the complexity of the theory of $operatorname{Gal}(mathbb Q)$.) However, using joint work with Kundu, we can show that once again there is no computable procedure for producing witnesses to the truth of (true) existential statements, either in the full group or in the subgroup.

Mass for the large and for the small
2024-12-03 11:00 - 12:00 | CMSA Room G10, CMSA, 20 Garden Street, Cambridge, MA, 02138, United States
General Relativity Seminar
Speaker: Tin Yau Tsang, Courant Institute, New York University
Title: Mass for the large and for the small

Abstract: Seeking a meaningful geometric (physical) invariant to describe a spacetime has sparked research in both mathematics and physics. In this talk, we will first see the fundamental progress made by Schoen-Yau and Witten on ADM (Arnowitt-Deser-Misner) mass. Then, we will see the progress on quasilocal masses in recent years. In particular, we would discuss the Hamiltonian formulation and the behaviour of quasilocal masses with the presence of apparent horizons.

Factorization Homology
2024-12-03 16:15 - 18:15 | Science Center Hall E, 1 Oxford Street, Cambridge, MA, 02138, United States
Geometry and Quantum Theory Seminar
Speakers: Sunghyuk Park and Vasily Krylov, Harvard CMSA
Title: Factorization Homology
