• General Relativity Conference

    CMSA 20 Garden Street, Cambridge, MA, United States

    https://www.youtube.com/playlist?list=PL0NRmB0fnLJTTVV5eLYJbJUHxi-3BipfS Schedule | April 4–8, 2022 Monday, April 4, 2022 Time (ET) Speaker Title/Abstract 9:30 am–10:30 am Pieter Blue, University of Edinburgh, UK (virtual) Title: Linear stability of the Kerr spacetime in the outgoing radiation gauge Abstract: This talk will discuss a new gauge condition (i.e. coordinate condition) for the Einstein equation, the linearisation of […]

  • Causality constraints on corrections to Einstein gravity

    Virtual

    Swampland Seminar Speakers: Simon Caron-Huot (McGill University) and Julio Parra (Caltech) Title: Causality constraints on corrections to Einstein gravity Abstract: We study constraints from causality and unitarity on 2→2 graviton scattering in four-dimensional weakly-coupled effective field theories. Together, causality and unitarity imply dispersion relations that connect low-energy observables to high-energy data. Using such dispersion relations, we derive two-sided bounds on gravitational Wilson coefficients […]

  • Second Annual Yip Lecture: Extraterrestrial Life

    Harvard Science Center 1 Oxford Street, Cambridge, MA

    Harvard CMSA hosted the second annual Yip Lecture on April 4, 2022. The Yip Lecture takes place thanks to the support of Dr. Shing-Yiu Yip. This year’s speaker was Avi Loeb (Harvard).   https://youtu.be/YV4Ki7x_yRc Extraterrestrial Life Abstract: Are we alone? It would be arrogant to think that we are, given that a quarter of all […]

  • Regularized integrals on Riemann surfaces and correlations functions in 2d chiral CFTs

    Virtual

    Abstract: I will report a recent approach of regularizing divergent integrals on configuration spaces of Riemann surfaces, introduced by Si Li and myself in arXiv:2008.07503, with an emphasis on genus one cases where modular forms arise naturally. I will then talk about some applications in studying correlation functions in 2d chiral CFTs, holomorphic anomaly equations, […]

  • What is Mathematical Consciousness Science?

    Speaker: Johannes Kleiner, LMU München Title: What is Mathematical Consciousness Science? Abstract: In the last three decades, the problem of consciousness – how and why physical systems such as the brain have conscious experiences – has received increasing attention among neuroscientists, psychologists, and philosophers. Recently, a decidedly mathematical perspective has emerged as well, which is now […]

  • Late time von Neumann entropy and measurement-induced phase transition

    Virtual

    Youtube Video   Abstract: Characterizing many-body entanglement is one of the most important problems in quantum physics. We present our studies on the steady state von Neumann entropy and its transition in Brownian SYK models. For unitary evolution, we show that the correlations between different replicas account for the Page curve at late time, and a […]

  • On the wave turbulence theory for a stochastic KdV type equation

    CMSA Room G10 CMSA, 20 Garden Street, Cambridge, MA, United States

    Random Matrix & Probability Theory Seminar Speaker: Minh-Binh TRAN (SMU & MIT) Location: CMSA, Room G02 Title: On the wave turbulence theory for a stochastic KdV type equation Abstract: We report recent progress, in collaboration with Gigliola Staffilani (MIT), on the problem of deriving kinetic equations from dispersive equations. To be more precise, starting from the stochastic  […]

  • Gopakumar-Vafa type invariants of holomorphic symplectic 4-folds

    Virtual

    Abstract: Gromov-Witten invariants of holomorphic symplectic 4-folds vanish and one can consider the corresponding reduced theory. In this talk, we will explain a definition of Gopakumar-Vafa type invariants for such a reduced theory. These invariants are conjectured to be integers and have alternative interpretations using sheaf theoretic moduli spaces. Our conjecture is proved for the product of […]

  • Lattice Gauge Theory View of Toric Codes, X-cube, and More

    Virtual

    Youtube Video   Abstract: Exactly solvable spin models such as toric codes and X-cube model have heightened our understanding of spin liquids and topological matter in two and three dimensions. Their exact solvability, it turns out, is rooted in the existence of commuting generators in their parent lattice gauge theory (LGT). We can understand the toric […]

  • Theories of branching morphogenesis

    Abstract: The morphogenesis of branched tissues has been a subject of long-standing debate. Although much is known about the molecular pathways that control cell fate decisions, it remains unclear how macroscopic features of branched organs, including their size, network topology and spatial pattern are encoded. Based on large-scale reconstructions of the mouse mammary gland and […]

  • The space of vector bundles on spheres: algebra, geometry, topology

    Abstract: Bott periodicity relates vector bundles on a topological space X to vector bundles on X “times a sphere”.   I’m not a topologist, so I will try to explain an algebraic or geometric incarnation, in terms of vector bundles on the Riemann sphere.   I will attempt to make the talk introductory, and (for the most part) […]

  • Synthetic Regression Discontinuity: Estimating Treatment Effects using Machine Learning

    Virtual

    Speaker: Jörn Boehnke Title: Synthetic Regression Discontinuity: Estimating Treatment Effects using Machine Learning Abstract:  In the standard regression discontinuity setting, treatment assignment is based on whether a unit’s observable score (running variable) crosses a known threshold.  We propose a two-stage method to estimate the treatment effect when the score is unobservable to the econometrician while the […]