# Mathematical Physics

This series consists of talks in the area of Mathematical Physics.

## Seminar Series Events/Videos

Currently there are no upcoming talks in this series.

## GKZ Hypergeometric Series for the Hesse Pencil, Chain Integrals and Orbifold Singularities

Thursday Oct 06, 2016
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I will talk about some connections among the GKZ (introduced by Gelfand-Kapranov-Zelevinsky) hypergeometric series, orbifold singularities of the system, and chain integrals in some geometry.  The GKZ hypergeometric series appeared in some very interesting contexts including arithmetic geometry, enumerative geometry and mathematical physics in the last few decades. I will report some new geometric realizations and interpretations of them.

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## Shifted Yangians, loop groups, and (co)products

Thursday Sep 29, 2016
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I'll describe a family of algebras called shifted Yangians, which arise as deformation quantizations of certain spaces related to loop groups.  I'll also describe coproducts for these algebras, which are related to multiplication in the loop group.  Physically, this fits into the story of Coulomb branches associated to 3d N=4 quiver gauge theories, where the above multiplication maps arises by taking products of scattering matrices.

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## Moonshine, topological modular forms, and 576 fermions.

Thursday Sep 22, 2016
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I will report on progress understanding the 576-fold periodicity in TMF in terms of conformal field theoretic constructions. Sporadic finite groups and their cohomology will play a role.

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## Monodromy of the Casimir connection and Coxeter categories

Thursday Sep 08, 2016
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A Coxeter category is a braided tensor category which carries an action of a generalised braid group $B_W$ on its objects. The axiomatics of a Coxeter category and the data defining the action of $B_W$ are similar in flavor to the associativity and commutativity constraints in a monoidal category, but arerelated to the coherence of a family of fiber functors.

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## Learning Seminar on Maulik-Okounkov

Thursday Jun 23, 2016
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## Learning seminar on Maulik-Okounkov

Tuesday Jun 07, 2016
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## Integrable systems and vacua of N=2* theories

Thursday Jun 02, 2016
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## Gluing in factorization homology via quantum Hamiltonian reduction

Thursday May 26, 2016
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Topological factorization homology is an invariant of manifolds which enjoys a hybrid of the structures in topological field theory, and in singular homology. These invariants are especially interesting when we restrict attention to the factorization homology of surfaces, with coefficients in braided tensor categories. In this talk, I would like to explain a technique, related to Beck monadicity, which allows us to compute these abstractly defined categories, as modules for explicitly computable, and in many cases well-known, algebras.

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## The A model and Lagrangian cobordisms

Thursday May 26, 2016

Physically, there's no reason to expect that the A model (as encoded by Gromov-Witten invariants and the Fukaya category) should be related to the theory of cobordisms between D branes. However, it seems that for the A model on convex symplectic targets, the theory of Lagrangian cobordisms detects many invariants of the Fukaya category, and may even recover it--put another way, it seems one can enrich the algebraic structures of the A model as being linear over cobordism spectra.

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## Cluster Theory is the Moduli Theory of A-branes in 4-manifolds

Thursday May 19, 2016
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We'll explain the slogan of the title: a cluster variety is a space associated to a quiver, and which is built out of algebraic tori.

They appear in a variety of contexts in geometry, representation theory, and physics. We reinterpret the definition as: from a quiver (and some additional choices) one builds an exact symplectic 4-manifold from which the cluster variety is recovered as a component in its moduli space of Lagrangian branes. In particular, structures from cluster algebra govern the classification of exact Lagrangian surfaces in Weinstein 4-manifolds.

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## LECTURES ON-DEMAND

### Roger Melko: Perimeter Institute and University of Waterloo

Speaker: Roger Melko