Talks in mathematical physics

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Spring Semester 2022

Date / Time Speaker Title Location
24 February 2022
15:15-16:15
Michele Del Zotto
Uppsala University, Sweden
Event Details

Talks in Mathematical Physics

Title Remarks on geometric engineering and correspondences
Speaker, Affiliation Michele Del Zotto, Uppsala University, Sweden
Date, Time 24 February 2022, 15:15-16:15
Location HG G 43
Abstract Over the past decade we have witnessed the emergence of a plethora of correspondences between QFTs in various dimensions arising from higher dimensional theories (famous examples include the AGT correspondence, the so called BPS/CFT correspondence, the 3d/3d correspondence, and others). In this talk I will overview another strategy to obtain correspondences building upon geometric engineering techniques in string theory. Several applications and examples will be presented, involving supersymmetric theories in different dimensions. In particular, we will comment on recent results about the higher Donaldson-Thomas theory for Calabi-Yau three-folds, generalizations of level/rank dualities, and the evidence for an algebra organizing instantons on G(2) manifolds.
Remarks on geometric engineering and correspondencesread_more
HG G 43
3 March 2022
15:15-16:15
Elba Garcia-Failde
Sorbonne Université
Event Details

Talks in Mathematical Physics

Title Witten’s r-spin conjecture and its negative counterpart
Speaker, Affiliation Elba Garcia-Failde, Sorbonne Université
Date, Time 3 March 2022, 15:15-16:15
Location HG G 43
Abstract In 1990, Witten conjectured that the generating series of intersection numbers of psi classes is a tau function of the KdV hierarchy. This was first proved by Kontsevich. In 2017, Norbury conjectured that the generating series of intersection numbers of psi classes with a negative square root of the canonical bundle is also a tau function of the KdV hierarchy. In ongoing work with N. Chidambaram and A. Giacchetto, we prove Norbury’s conjecture and obtain polynomial relations among kappa classes which were recently conjectured by Kazarian--Norbury. We also extend the conjecture to (negative) r-th roots (previously r=2) and prove that the corresponding intersection numbers can also be computed recursively using topological recursion (which I will briefly introduce) and W-constraints. The strategy draws inspiration from our proof, together with S. Charbonnier, of Witten’s r-spin conjecture from 1993 (Faber—Shadrin—Zvonkine’s theorem from 2010), which corresponds to the positive side of the story. We also obtain tautological relations in the (negative) analogous way to Pandharipande--Pixton--Zvonkine. The talk will be an overview of these four topics (r=2/>2; positive/negative) and their connections.
Witten’s r-spin conjecture and its negative counterpartread_more
HG G 43
10 March 2022
15:15-16:15
Donald Youmans
University of Bern
Event Details

Talks in Mathematical Physics

Title Darboux coordinates for hyperbolic Virasoro coadjoint orbits
Speaker, Affiliation Donald Youmans, University of Bern
Date, Time 10 March 2022, 15:15-16:15
Location HG G 43
Abstract In this talk, we define Darboux coordinates for hyperbolic Virasoro coadjoint orbits with constant representative. These coordinates allow for many explicit computations, such as the partition function and several time-ordered and out-of-time ordered correlation functions, in the so-called Schwarzian theory which, in recent years, has gotten a lot of attention in both, mathematics and physics. This talk is based on joint work with Anton Alekseev and Olga Chekeres.
Darboux coordinates for hyperbolic Virasoro coadjoint orbitsread_more
HG G 43
31 March 2022
15:15-16:15
Miquel Cueca
Georg-August-Universität, Göttingen
Event Details

Talks in Mathematical Physics

Title Dimensional reduction of Courant sigma models
Speaker, Affiliation Miquel Cueca, Georg-August-Universität, Göttingen
Date, Time 31 March 2022, 15:15-16:15
Location HG G 43
Abstract I will show that the 2d Poisson sigma model with target a Poisson groupoid arises as an effective theory of the 3d Courant sigma model associated to the double of the corresponding Lie bialgebroid. This is joint work with Alejandro Cabrera.
Dimensional reduction of Courant sigma modelsread_more
HG G 43
7 April 2022
15:15-16:15
Fridrich Valach
Imperial College
Event Details

Talks in Mathematical Physics

Title Higher Poisson-Lie T-dualities
Speaker, Affiliation Fridrich Valach, Imperial College
Date, Time 7 April 2022, 15:15-16:15
Location HG G 43
Abstract I will describe a general BV framework for studying dualities of Poisson-Lie type. This puts on the same footing the ordinary Poisson-Lie T-duality and the electric-magnetic duality, and leads to a new family of dualities of higher gauge theories. An important role will be played by (a "baby" version of) the derived intersection of Lagrangians of Pantev-Toën-Vaquié-Vezzosi. This is a joint work with Ján Pulmann and Pavol Ševera (arXiv:1909.06151).
Higher Poisson-Lie T-dualitiesread_more
HG G 43
12 May 2022
15:15-16:15
Dr. Danica Kosanović
ETH Zurich, Switzerland
Event Details

Talks in Mathematical Physics

Title Graph complexes in knot theory
Speaker, Affiliation Dr. Danica Kosanović, ETH Zurich, Switzerland
Date, Time 12 May 2022, 15:15-16:15
Location HG G 43
Abstract Quantum link invariants of Reshetikhin and Turaev can be factored through certain universal link invariants whose target is a certain algebra of graphs. In this talk I will explain what these graphs have to do with configuration spaces and operads, and why they offer a computable approach for the study of embedding spaces.
Graph complexes in knot theoryread_more (CANCELLED)
HG G 43
19 May 2022
15:15-16:15
Simone Noja
Ruprecht-Karls-Universität Heidelberg
Event Details

Talks in Mathematical Physics

Title The de Rham / Spencer double complex and the geometry of forms on supermanifolds
Speaker, Affiliation Simone Noja, Ruprecht-Karls-Universität Heidelberg
Date, Time 19 May 2022, 15:15-16:15
Location HG G 43
Abstract Integral forms are characteristic supergeometric objects that allow to define a meaningful notion of integration on supermanifolds. In this talk I will introduce a double complex of non-commutative sheaves which related integral forms to the more customary notion of differential forms. I will then discuss how this framework specializes to the so-called cotangent bundle supermanifolds, which are relevant to odd symplectic geometry and BV theory. If time permits, I will explain how the geometry of forms is related to the problem of splitting a complex supermanifold in this particular setting.
The de Rham / Spencer double complex and the geometry of forms on supermanifoldsread_more
HG G 43
26 May 2022
15:15-16:15
Ivan Contreras
Amherst College
Event Details

Talks in Mathematical Physics

Title Frobenius objects in the category of spans and the symplectic category
Speaker, Affiliation Ivan Contreras, Amherst College
Date, Time 26 May 2022, 15:15-16:15
Location HG G 43
Abstract It is well known that Frobenius algebras are in correspondence with 2-dimensional TQFT. In this talk, we introduce Frobenius objects in any monoidal category and in particular, in the category where objects are sets and morphisms are spans of sets. We prove the existence of a simplicial set that encodes the data of the Frobenius structure in this category. This serves as a (simplicial) toy model of the Wehrheim-Woodward construction for the symplectic category. This is part of a program that intends to describe, in terms of category theory, the relationship between symplectic groupoids and topological field theory, via the Poisson sigma model. Based on joint work with Rajan Mehta and Molly Keller (arXiv:2106.14743), and ongoing work with Rajan Mehta and Walker Stern.
Frobenius objects in the category of spans and the symplectic categoryread_more
HG G 43
2 June 2022
15:15-16:15
Eugene Rabinovich
Notre Dame University
Event Details

Talks in Mathematical Physics

Title Classical Bulk-Boundary Correspondences via Factorization Algebras
Speaker, Affiliation Eugene Rabinovich, Notre Dame University
Date, Time 2 June 2022, 15:15-16:15
Location HG G 43
Abstract A factorization algebra is a cosheaf-like local-to-global object which is meant to model the structure present in the observables of classical and quantum field theories. In the Batalin-Vilkovisky (BV) formalism, one finds that a factorization algebra of classical observables possesses, in addition to its factorization-algebraic structure, a compatible Poisson bracket of cohomological degree +1. Given a ``sufficiently nice'' such factorization algebra on a manifold $N$, one may associate to it a factorization algebra on $N\times \mathbb{R}_{\geq 0}$. The aim of the talk is to explain the sense in which the latter factorization algebra ``knows all the classical data'' of the former. This is the bulk-boundary correspondence of the title. Time permitting, we will describe how such a correspondence appears in the deformation quantization of Poisson manifolds.
Classical Bulk-Boundary Correspondences via Factorization Algebrasread_more
HG G 43
6 July 2022
14:00-15:00
Domenico Fiorenza
Sapienza Università di Roma
Event Details

Talks in Mathematical Physics

Title String bordism invariants in dimension 3 from U(1)-valued TQFTs
Speaker, Affiliation Domenico Fiorenza, Sapienza Università di Roma
Date, Time 6 July 2022, 14:00-15:00
Location HG G 19.1
Abstract The third string bordism group is known to be Z/24Z. Using Waldorf's notion of a geometric string structure on a manifold, Bunke--Naumann and Redden have exhibited integral formulas involving the Chern-Weil form representative of the first Pontryagin class and the canonical 3-form of a geometric string structure that realize the isomorphism Bord3String to Z/24Z (these formulas have been recently rediscovered by Gaiotto--Johnson-Freyd--Witten). In the talk I will show how these formulas naturally emerge when one considers the U(1)-valued 3d TQFTs associated with the classifying stacks of Spin bundles with connection and of String bundles with geometric structure. Based on joint work with Eugenio Landi (in preparation).
String bordism invariants in dimension 3 from U(1)-valued TQFTsread_more
HG G 19.1
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