What do topological dynamics, combinatorics, and model theory have in common?

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

Speaker: Dana Bartosova (University of Florida) Title: What do topological dynamics, combinatorics, and model theory have in common? Abstract: A striking correspondence between dynamics of automorphism groups of countable first order structures and Ramsey theory of finitary approximation of the structures was established in 2005 by Kechris, Pestov, and Todocevic. Since then, their work has been generalized […]

Remarkable symmetries of rotating black holes

https://youtu.be/cSgyLwg0v00 General Relativity Seminar Speaker: David Kubiznak (Charles University) Title: Remarkable symmetries of rotating black holes Abstract: It is well known that the Kerr geometry admits a non-trivial Killing tensor and its 'square root' known as the Killing-Yano tensor. These two objects stand behind Carter's constant of geodesic motion as well as allow for separability of test […]

A random matrix model towards the quantum chaos transition conjecture

Probability Seminar Speaker: Jun Yin (UCLA) Title: A random matrix model towards the quantum chaos transition conjecture Abstract: The Quantum Chaos Conjecture has long fascinated researchers, postulating a critical spectrum phase transition that separates integrable systems from chaotic systems in quantum mechanics. In the realm of integrable systems, eigenvectors remain localized, and local eigenvalue statistics […]

Anomalous Landau level analog in solids: search and implications for 2d heterostructures

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

https://youtu.be/fB9xJyJj8zU Topological Quantum Matter Seminar Speaker: Valentin Crepel, Flatiron Institute Title: Anomalous Landau level analog in solids: search and implications for 2d heterostructures Abstract: The recent experimental observation of fractional Chen insulators — the analog of fractional quantum Hall states realized in absence of any applied magnetic field — calls for more detailed theoretical investigations […]

A Gaussian convexity for logarithmic moment generating function

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

Probability Seminar Speaker: Wei-Kuo Chen (University of Minnesota) Title: A Gaussian convexity for logarithmic moment generating function Abstract: Convex functions of Gaussian vectors are prominent objectives in many fields of mathematical studies. In this talk, I will establish a new convexity for the logarithmic moment generating function for this object and draw two consequences. The first leads to […]

An introduction to mixture of experts in deep learning

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

Member Seminar Speaker: Samy Jelassi Title: An introduction to mixture of experts in deep learning Abstract: Scale has opened new frontiers in natural language processing – but at a high cost. Mixture-of-Experts (MoE) have been proposed as a path to even larger and more capable language models. They select different parameters for each incoming example. By […]

A Plane Defect in the 3d O(N) Model

Hybrid

Quantum Matter Seminar Speaker: Abijith Krishnan (MIT) Title: A Plane Defect in the 3d O(N) Model Abstract: It was recently found that the classical 3d O(N) model in the semi-infinite geometry can exhibit an "extraordinary-log" boundary universality class, where the spin-spin correlation function on the boundary falls off as (log x)^(-q). This universality class exists for […]

Quantum information: the interplay of mathematics and physics

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

Topological Quantum Matter Seminar Speaker: Kaifeng Bu (Harvard University) Title: Quantum information: the interplay of mathematics and physics Abstract: I will provide an introduction to quantum information, which points to a new connection with experiment on the one hand, and a potential new area of mathematical analysis on the other. I will introduce two recent results about […]

CM-minimizers and standard models of Fano fibrations over curves

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

Algebraic Geometry in String Theory Seminar Speaker: Maksym Fedorchuk (Boston College) Title: CM-minimizers and standard models of Fano fibrations over curves Abstract: A recent achievement in K-stability of Fano varieties is an algebro-geometric construction of a projective moduli space of K-polystable Fanos. The ample line bundle on this moduli space is the CM line bundle […]

The Fractional Quantum Hall Effect at ν=5/2: Past, Recent, and Future

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

https://youtu.be/2CbIDgFFzRY Topological Quantum Matter Seminar Speaker:  Ken K. W. Ma (Northeastern University) Title: The Fractional Quantum Hall Effect at ν=5/2: Past, Recent, and Future Abstract: The discovery of fractional quantum Hall (FQH) states started a new chapter in modern physics. Nowadays, more than 70 FQH states at different filling factors have been observed. Among them, the […]

Analysis of ALH* gravitational instantons

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

Speaker: Xuwen Zhu (Northeastern) Title: Analysis of ALH* gravitational instantons Abstract: Gravitational instantons are non-compact Calabi-Yau metrics with L^2 bounded curvature and are categorized into six types. We will discuss one such type called ALH* metrics which has a non-compact end modelled by the Calabi ansatz with inhomogeneous collapsing near infinity. Such metrics appeared recently in the works on SYZ conjecture, […]

The Feynman propagator and self-adjointness

Virtual

https://youtu.be/xTnSasVv4_0 General Relativity Seminar Speaker: Andras Vasy (Stanford) Title: The Feynman propagator and self-adjointness Abstract: In this talk I will discuss the Feynman and anti-Feynman inverses for wave operators on certain Lorentzian manifolds; these are two inverses which from a microlocal analysis perspective are more natural than the standard causal (advanced/retarded) ones. For instance, for the spectral family […]