COVID-19 information for PI Residents and Visitors
Equivariant elliptic cohomology is a rapidly evolving field, with wideranging applications including in quantum field theory, geometric representation theory, integrable systems, singularity theory, combinatorial representation theory, homotopy theory, and group theory. Physics in particular has been present starting early in the elliptic cohomology story with Witten's 1987 recognition of the elliptic genus as a supersymmetric partition function. Moonshine and orbifold conformal field theory contributed deeply to the development of equivariant elliptic cohomology. Modern physical applications include using elliptic cohomology to see subtle torsion constraints on phases of supersymmetric field theories and to explain (mock) modularity phenomena. Future applications may include elliptic upgrades of K-theoretic methods in condensed matter. This workshop aims to bring together the emerging international community interested in this circle of ideas. The workshop will be held entirely online, with two lectures each day and ample time for discussion, with efforts made to accommodate time-zone differences. This should allow participation from people who, for reasons of distance or family, do not normally travel to such conferences.
Registration for this conference is now closed.
- Miranda Cheng, University of Amsterdam
- Davide Gaiotto, Perimeter Institute
- Fei Han, National University of Singapore
- Zhen Huan, Huazhong University of Science and Technology
- Nitu Kitchloo, Johns Hopkins University
- Gerd Laures, Ruhr-Universität Bochum
- Lennart Meier, Utrecht University
- Jack Morava, Johns Hopkins University
- Richard Rimanyi, University of North Carolina at Chapel Hill
- Arnav Tripathy, Harvard University
- Brian Williams, Northeastern University
- Kirillov Anatol, Kyoto University
- Andrew Baker, University of Glasgow
- Francis Bischoff, University of Oxford
- Tommaso Botta, ETH Zurich
- Emily Cliff, University of Sydney
- Mattia Coloma, Tor Vergata University of Rome
- Stefano D'Alesio, ETH Zurich
- Jorge Devoto, University of Buenos Aires
- Tom Dove, University of Melbourne
- Anne Dranowski, University of Toronto
- Chris Elliott, University of Massachusetts Amherst
- Giovanni Felder, ETH Zurich
- Domenico Fiorenza, Sapienza University of Rome
- Vassily Gorbounov, University of Aberdeen
- Meng Guo, Perimeter Institute
- André Henriques, University of Oxford
- Tatsuyuki Hikita, Kyoto University
- Gerald Hoehn, Kansas State University
- Michael Hopkins, Harvard University
- Mikhaiil Kapranov, Kavli IPMU
- Syu Kato, Kyoto University
- Ali Khalili Samani, University of Tehran
- Yuqin Kewang, University of Chinese Academy of Sciences
- Hitoshi Konno, Tokyo University of Marine Science and Technology
- Eugenio Landi, Roma Tre University
- Cristian Lenart, State University of New York at Albany
- Anatoly Libgober, University of Illinois at Chicago
- Gregory Moore, Rutgers University
- Benedict Morrissey, University of Pennsylvania
- Kohei Motegi, Tokyo University of Marine Science and Technology
- Apurva Nakade, University of Western Ontario
- Masaki Nakagawa, Okayama University
- Hiroshi Naruse, University of Yamanashi
- Niko Naumann, Unversity of Regensburg
- Arun Ram, University of Melbourne
- Doug Ravenel, University of Rochester
- Charles Rezk, University of Illinois At Urbana-Champaign
- Sarah Scherotzke, University of Luxembourg
- Eric Sharpe, Virginia Polytechnic Institute and State University
- Yiyan Shou, University of North Carolina at Chapel Hill
- Nicolò Sibilla, SISSA
- Matthew Spong, University of Melbourne
- Nathaniel Stapleton, University of Kentucky
- Stephan Stolz, University of Notre Dame
- Norio Suzuki, Kitami Institute of Technology
- Matt Szczesny, Boston University
- Shohei Tanaka, Fukuoka University
- Valerio Toledano Laredo, Northeastern University
- Kazushi Ueda, University of Tokyo
- Alexander Varchenko, University of North Carolina at Chapel Hill
- Michele Vergne, Mathematics Institute of Jussieu–Paris Rive Gauche
- Achal Vinod, Shiv Nadar University
- Hideya Watanabe, Kyoto University
- Andrzej Weber, University of Warsaw
- Matt Young, Max Planck Institute for Mathematics
- Kirill Zainoulline, University of Ottawa
- Valentin Zakharevich, Johns Hopkins University
- Chengjing Zhang, University of Melbourne
- Changlong Zhong, State University of New York at Albany
- Paul Zinn-Justin, University of Melbourne
Monday, May 25, 2020
Time |
Event |
Location |
8:55 – 9:00am |
Theo Johnson-Freyd, Perimeter Institute |
Virtual |
9:00 – 10:00am |
Fei Han, National University of Singapore |
Virtual |
7:00 – 8:00pm |
Davide Gaiotto, Perimeter Institute |
Virtual |
Tuesday, May 26, 2020
Time |
Event |
Location |
9:00 – 10:00am |
Lennart Meier, Utrecht University |
Virtual |
11:00 – 12:00pm |
Arnav Tripathy, Harvard University |
Virtual |
7:00 – 8:00pm |
Jack Morava, Johns Hopkins University |
Virtual |
Wednesday, May 27, 2020
Time |
Event |
Location |
9:00 – 10:00am |
Gerd Laures, Ruhr-Universität Bochum |
Virtual |
11:00 – 12:00pm |
Brian Williams, Northeastern University |
Virtual |
7:00 – 8:00pm |
Richard Rimanyi, University of North Carolina at Chapel Hill |
Virtual |
Thursday, May 28, 2020
Time |
Event |
Location |
9:00 – 10:00am |
Miranda Cheng, University of Amsterdam |
Virtual |
11:00 – 12:00pm |
Zhen Huan, Huazhong University of Science and Technology |
Virtual |
7:00 – 8:00pm |
Nitu Kitchloo, Johns Hopkins University |
Virtual |
Miranda Cheng, University of Amsterdam
Sigma-VOA correspondence
In this talk I will discuss an interesting phenomenon, namely a correspondence between sigma models and vertex operator algebras, with the two related by their symmetry properties and by a reflection procedure, mapping the right-movers of the sigma model at a special point in the moduli space to left-movers. We will discuss the examples of N=(4,4) sigma models on $T^4$ and on $K3$. The talk will be based on joint work with Vassilis Anagiannis, John Duncan and Roberto Volpato.
Davide Gaiotto, Perimeter Institute
Topological Modular Forms and Quantum Field Theory
Fei Han, National University of Singapore
Projective elliptic genera and applications
Projective vector bundles (or gerbe modules) are generalizations of vector bundles in the presence of a gerbe on manifolds. Given a projective vector bundle, we will first show how to use it to twist the Witten genus to get modular invariants, which we call projective elliptic genera. Then we will give two applications: (1) given any pseudodifferential operator, we will construct modular invariants generalizing the Witten genus, which corresponds to the Dirac operator; (2) we will enhance the Hori map in T-duality to the graded Hori map and show that it sends Jacobi forms to Jacobi forms. This represents our joint works with Mathai.
Zhen Huan, Huazhong University of Science and Technology
Quasi-elliptic cohomology theory and the twisted, twisted Real theories
Quasi-elliptic cohomology is closely related to Tate K-theory. It is constructed as an object both reflecting the geometric nature of elliptic curves and more practicable to study than most elliptic cohomology theories. It can be interpreted by orbifold loop spaces and expressed in terms of equivariant K-theories. We formulate the complete power operation of this theory. Applying that we prove the finite subgroups of Tate curve can be classified by the Tate K-theory of symmetric groups modulo a certain transfer ideal.
In addition, we define twisted quasi-elliptic cohomology. They can be related to a twisted equivariant version Devoto’s elliptic cohomology via a Chern character map. Moreover, we construct twisted Real quasi-elliptic cohomology and the Chern character map in this case. This is joint work with Matthew Spong and Matthew Young.
Nitu Kitchloo, Johns Hopkins University
Conformal blocks in genus zero, and Elliptic cohomology
A fundamental theorem in the theory of Vertex algebras (known as Zhu’s theorem) demonstrates that the space generated by the characters of certain Vertex algebras is a representation of the modular group. We will cast this theorem in the language of homotopy theory using the language of conformal blocks. The goal of this talk is to justify the claim that equivariant elliptic cohomology, seen as a derived spectrum, is a homotopical analog of Zhu’s theorem in the special case of the Affine Vacuum vertex algebra at a fixed integral level. The talk will not require knowing the definition of Vertex algebras or conformal blocks.
Gerd Laures, Ruhr-Universität Bochum
Codes, vertex algebras and topological modular forms
The talk illuminates the role of codes and lattice vertex algebras in algebraic topology. These objects come up naturally in connection with string structures or topological modular forms. The talk tries to unify these different concepts in an introductory manner.
Lennart Meier, Utrecht University
Equivariant elliptic cohomology with integral coefficients
Thirteen years ago, Lurie has sketched a way to obtain equivariant elliptic cohomology and equivariant topological modular forms without the need to restrict to rational or complex coefficients. Recently, David Gepner and I have found one way to flesh out the details and and provide computations in the U(1)-equivariant case. On this work I will report.
Jack Morava, Johns Hopkins University
Quasisymmetric characteristic numbers for Hamiltonian toric manifolds.
Baker and Richter's $A_\infty$ analog of the complex cobordism spectrum provides characteristic numbers for complex-oriented toric manifolds, which generalize to define similar invariants for Hamiltonian toric dynamical systems: roughly, the `completely integrable' systems of classical mechanics which (by KAM theory) possess remarkable stability properties. arXiv:1910.12609
https://www.youtube.com/watch?v=w_bQuhNq7A0
Richard Rimanyi, University of North Carolina
Elliptic characteristic classes, bow varieties, 3d mirror duality
We study elliptic characteristic classes of natural subvarieties in some ambient spaces, namely in homogeneous spaces and in Nakajima quiver varieties. The elliptic versions of such characteristic classes display an unexpected symmetry: after switching the equivariant and the Kahler parameters, the classes of varieties in one ambient space ``coincide” with the classes of varieties in another ambient space. This duality gets explained as “3d mirror duality” if we regard our ambient spaces as special cases of Cherkis bow varieties. I will report on a work in progress with Y. Shou, based on earlier related works with G. Felder, A. Smirnov, V. Tarasov, A. Varchenko, A. Weber, Z. Zhou.
Arnav Tripathy, Harvard University
The de Rham model for elliptic cohomology from physics
I'll discuss elliptic cohomology from a physical perspective, indicating the importance of the Segal-Stolz-Teichner conjecture and joint work with D. Berwick-Evans on rigorously proving some of these physical predictions.
Brian Williams, Northeastern University
Twisted superconformal algebras and representations of higher Virasoro algebras
(Super)conformal algebras on two-dimensional spacetimes play a ubiquitous role in representation theory and conformal field theory. In most cases, however, superconformal algebras are finite dimensional. In this talk, we introduce refinements of certain deformations of superconformal algebras which share many facets with the ordinary (super) Virasoro algebras. Representations of these refinements include the higher dimensional Kac—Moody algebras, and many more motivated by physics. Finally, we will show how these algebras enhance to higher dimensional chiral/factorization algebras which upon ``localization" deform to well-studied chiral algebras on Riemann surfaces.
Projective elliptic genera and applications
Projective vector bundles (or gerbe modules) are generalizations of vector bundles in the presence of a gerbe on manifolds. Given a projective vector bundle, we will first show how to use it to twist the Witten genus to get modular invariants, which we call projective elliptic genera. Then we will give two applications: (1) given any pseudodifferential operator, we will construct modular invariants generalizing the Witten genus, which corresponds to the Dirac operator; (2) we will enhance the Hori map in T-duality to the graded Hori map and show that it sends Jacobi forms to Jacobi forms.
Pages
Scientific Organizers:
- Daniel Berwick Evans, University of Illinois at Urbana-Champaign
- Nora Ganter, University of Melbourne
- Theo Johnson-Freyd, Perimeter Institute
- Yaping Yang, University of Melbourne
- Gufang Zhao, University of Melbourne