• Categorification and applications

    Virtual

    Speaker: Peng Shan (Tsinghua University) Title: Categorification and applications Abstract: I will give a survey of the program of categorification for quantum groups, some of its recent development and applications to representation theory.

  • D3C: Reducing the Price of Anarchy in Multi-Agent Learning

    Virtual

    Speaker: Ian Gemp, DeepMind Title: D3C: Reducing the Price of Anarchy in Multi-Agent Learning Abstract: In multi-agent systems the complex interaction of fixed incentives can lead agents to outcomes that are poor (inefficient) not only for the group but also for each individual agent. Price of anarchy is a technical game theoretic definition introduced to quantify the […]

  • A tour of categorical symmetry

    Virtual

    Title: A tour of categorical symmetry Abstract: I will discuss some perspectives on symmetry coming from the study of topological defects in quantum field theory. I will argue that we should take topological defects themselves to define the symmetries of QFT. This gives us a view of the “category of QFTs”. I will describe some […]

  • Line defects in CFTs: Renormalization group flows and semiclassical limits

    Virtual

    Title: Line defects in CFTs: Renormalization group flows and semiclassical limits Abstract: I will discuss line defects in d-dimensional Conformal Field Theories (CFTs). In the first part of the talk, I will argue that the ambient CFT places nontrivial constraints on Renormalization Group (RG) flows on such line defects. I will show that the flow […]

  • Strings, knots and quivers

    Virtual

    Speaker: Piotr Sułkowski (University of Warsaw) Title: Strings, knots and quivers Abstract: I will discuss a recently discovered relation between quivers and knots, as well as – more generally – toric Calabi-Yau manifolds. In the context of knots this relation is referred to as the knots-quivers correspondence, and it states that various invariants of a given knot […]

  • Math Science Lectures in Honor of Raoul Bott: Michael Freedman

    Virtual

    On October 4th and October 5th, 2021, Harvard CMSA hosted the annual Math Science Lectures in Honor of Raoul Bott. This year’s speaker was Michael Freedman (Microsoft). The lectures took place on Zoom. This will be the third annual lecture series held in honor of Raoul Bott. Lecture 1 October 4th, 11:00am (Boston time) Title: The Universe from a […]

  • Langlands duality for 3 manifolds

    Virtual

    Speaker: David Jordan (U Edinburgh) Title: Langlands duality for 3 manifolds Abstract: Langlands duality began as a deep and still mysterious conjecture in number theory, before branching into a similarly deep and mysterious conjecture of Beilinson and Drinfeld concerning the algebraic geometry of Riemann surfaces. In this guise it was given a physical explanation in the framework of 4-dimensional super […]

  • Oscillations in the thermal conductivity of a spin liquid*

    Virtual

    Title: Oscillations in the thermal conductivity of a spin liquid* Abstract: The layered honeycomb magnet alpha-RuCl3 orders below 7 K in a zigzag phase in zero field. An in-plane magnetic field H||a suppresses the zigzag order at 7 Tesla, leaving a spin-disordered phase widely believed to be a quantum spin liquid (QSL) that extends to […]

  • Applications of instantons, sphalerons and instanton-dyons in QCD

    Virtual

    Title: Applications of instantons, sphalerons and instanton-dyons in QCD Abstract: I start with a general map of gauge topology, including monopoles, instantons and instanton-dyons. Then comes reminder of the “topological landscape”, the minimal energy gauge field configurations, as a function of Chern-Simons number Ncs and r.m.s. size. It includes “valleys” at integer Ncs separated by […]

  • The number of n-queens configurations

    Virtual

    Speaker: Michael Simkin, Harvard CMSA Title: The number of n-queens configurations Abstract: The n-queens problem is to determine Q(n), the number of ways to place n mutually non-threatening queens on an n x n board. The problem has a storied history and was studied by such eminent mathematicians as Gauss and Polya. The problem has also […]

  • Symmetry types in QFT and the CRT theorem

    Virtual

    Title: Symmetry types in QFT and the CRT theorem Abstract: I will discuss ideas around symmetry and Wick rotation contained in joint work with Mike Hopkins (https://arxiv.org/abs/1604.06527). This includes general symmetry types for relativistic field theories and their Wick rotation.  I will then indicate how the basic CRT theorem works for general symmetry types, focusing […]