Colloquium

Speaker: Matthew Foreman (UC Irvine) Title: Impossibility results in classical dynamical systems Abstract: In 1932, motivated by questions in statistical and celestial mechanics, von Neumann proposed classifying the statistical behavior of dynamical systems. In the 1960's, motivated by work of Poincaré, Smale proposed classifying the qualitative behavior of dynamical systems.  These questions laid the groundwork for enormous amounts of work, but […]

Speaker: Brian Williams (Boston University) Title: Koszul duality in QFT Abstract: We will describe appearances of the algebraic phenomena of Koszul duality in the context of boundary conditions and defects in quantum field theory. Primarily motivated by topological string theory, this point of view was pioneered by Costello and Li in their proposal for a […]

Speaker: Jeff W. Lichtman (Harvard University) Title: The analytical challenges of connectomics Abstract: Recent progress in generating synapse-level maps of brains, a field known as connectomics, brings both opportunities and challenges. The upside is that the biophysical instantiation of memories, behaviors, and knowledge will soon be before us. The downside is that no one knows exactly how […]

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 […]

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, […]

Colloquium Speaker: Justin Moore (Cornell University) Title: Homology, higher derived limits, and set theory Abstract: Singular homology has a number of well-known defects when used to study spaces such as the Hawaiian earring and solenoids. It may not reflect the "shape" of the space and can give counterintuitive information about its dimension. One remedy of […]

Colloquium Speaker: Clark Barwick, University of Edinburgh Title: Factorization algebras in quite a lot of generality Abstract: The objects of arithmetic geometry are not manifolds. Some concepts from differential geometry admit analogues in arithmetic, but they are not straightforward. How then can we hope to make precise sense of quantum field theories on these objects? […]

Colloquium Speaker: Raghu Meka (UCLA) Title: Strong bounds for arithmetic progressions Abstract: Suppose you have a set S of integers from {1,2,...,N} that contains at least N / C elements. Then for large enough N, must S contain three equally spaced numbers (i.e., a 3-term arithmetic progression)? In 1953, Roth showed this is the case […]

Colloquium Speaker: Natalie Paquette, University of Washington Title: Koszul duality & twisted holography for asymptotically flat spacetimes Abstract: Koszul duality has been understood in recent years to characterize order-type defects in twists of supersymmetric field theories. This notion has been generalized, from a physical point of view, by studying couplings between D-branes and closed string […]

Colloquium Speaker: Lance Dixon (SLAC, Stanford University) Title: The DNA of Particle Scattering Abstract: At the Large Hadron Collider, the copious scattering of quarks and gluons in quantum chromodynamics (QCD) produces Higgs bosons and many backgrounds to searches for new physics.  At short distances, scattering in QCD can be evaluated in perturbation theory and leads to highly […]

Colloquium Speaker: Sarah Harrison (Northeastern University) Title: Liouville Theory and Weil-Petersson Geometry Abstract: Two-dimensional conformal field theory is a powerful tool to understand the geometry of surfaces. Liouville conformal field theory in the classical (large central charge) limit encodes the geometry of the moduli space of Riemann surfaces. I describe an efficient algorithm to compute […]