Workshop 2012
From Poisson to String Geometry
Department Mathematik, FriedrichAlexanderUniversität ErlangenNürnberg
Erlangen, September 11 – 14 2012
Photograph by Johanna Kulzer
Scientific Objective
Both, applications in mathematical physics and the study of Poisson geometry have lead to the consideration of higher categorical geometrical structures, for example higher generalizations of bundles. A profound source for such structures has been the study of sigma models, in particular in its application to the quantization of Poisson manifolds. We plan to bring together people working on Poisson geometry, on higher categorical structures and mathematical physicists. A direction that we want to emphasize for future research are higher categorical structures occurring in the description of geometric string structures.
Speakers
Confirmed speakers include:
 Christian Becker, Universität Potsdam
 Lawrence Breen, Université Paris 13
 Ulrich Bunke, Universität Regensburg
 Henrique Bursztyn, IMPA, Rio de Janeiro
 Marius Crainic, Utrecht University
 Giovanni Felder, ETH Zürich
 Ezra Getzler, Northwestern University
 Gerd Laures, RuhrUniversität Bochum
 Pavel Mnev, ETH Zürich
 Jouko Mickelsson, University of Helsinki
 Dmitry Roytenberg, University of Nijmegen / Utrecht University
 Urs Schreiber, Utrecht University
 Danny Stevenson, University of Glasgow
 Christian Voigt, University of Glasgow
 Tilmann Wurzbacher, RuhrUniversität Bochum
 Marco Zambon, Universidad Autonoma de Madrid, ICMAT
Programme
Time  Tuesday Sept. 11  Wednesday Sept 12  Thursday Sept 13  Friday Sept 14 

9:30  Registration  Schreiber  
10:00  Getzler  Bursztyn  Breen  
10:30  Coffee Break  
11:00  Coffee break  Coffee break  Coffee break  Zambon 
11:30  Felder  Voigt  Mnev  
12:00  Lunch break  
12:30  Lunch break  Lunch break  Lunch break  
13:30  Stevenson  
14:00  
14:30  Bunke  Mickelsson  Becker  Coffee Break 
15:00  Wurzbacher  
15:30  Coffee Break  Coffee Break  Coffee Break  
16:00  Crainic  Roytenberg  Laures  
16:30  
17:00  Welcome  
18:30  
19:00  Conference Dinner  
19:30 
Lunch Breaks
Lunch will be provided at the university restaurant in the same building. There will be a choice of different dishes, including meat or fish, vegetarian options and a salad bar.
Welcome
On Tuesday, September 11, there will be an informal welcome with beer and pretzels directly after the last talk. It will take place in the conference building.
Conference Dinner
The conference dinner will take place Thursday, September 13, 7:00 pm at
the restaurant Schwarzer Bär, Innere Brucker Straße 19, 91054 Erlangen. The restaurant is in Erlangen city centre in walking distance from all hotels (Map).
Talks
 Christian Becker, Universität Potsdam:
CheegerChernSimons Theory and Geometric String StructuresI will explain the notion of differential characters with sections along a smooth map and their covariant derivatives. The CheegerSimons characters have canonical sections with covariant derivative the ChernSimons form.This yields a notion of geometric String structures. I will further explain fiber integration for differential characters. This leads to higher dimensional transgressions with properties analogous to topological quantum field theories in the sense of Atiyah.(Slides)  Lawrence Breen, Université Paris 13:
Functorial homology and geometryI will discuss certain functorial aspects of the homology and cohomology of groups and EilenbergMac Lane spaces, and related geometric constructions.  Ulrich Bunke, Universität Regensburg:
Differential cohomology – the spectrum aspect  Henrique Bursztyn, IMPA, Rio de Janeiro:
Multiplicative structures on Lie groupoids
Symplectic groupoids are central objects in Poisson geometry which naturally arise in the theory of (Poisson) sigma models. A simplectic groupoid is a Lie groupoid equipped with a symplectic form which is suitably compatible with the groupoid structure, in the sense that it is “multiplicative”. The talk will discuss more general multiplicative geometric structures on Lie groupoids and describe their associated infinitesimal geometries, extending the correspondence between Poisson structures and symplectic groupoids.  Marius Crainic, Utrecht University:
Multiplicative forms and Spencer operatorsI will discuss multiplicative forms with coefficients and explain an integrability theorem in this context, inspired from Cartan’s theory of Lie pseudogroups and literature that followed it (the geometry of PDE and exterior differential systems). This is based on joint work with Maria Amelia Salazar and Ivan Struchiner.  Giovanni Felder, ETH Zürich:
The classical master equationWe formalize the construction of Batalin and Vilkovisky of a solution of the master equation associated with a polynomial in n variables (or a regular function on a nonsingular affine variety). We show existence and uniqueness up to “stable equivalence” and discuss the associated BRST cohomology (joint work with David Kazhdan).  Ezra Getzler Northwestern University:
The Poisson Lie nalgebra in classical field theory
I will discuss the role of Linfinity algebras in classical field theory, especially in the presence of supersymmetry.  Gerd Laures, RuhrUniversität Bochum:
On characteristic classes in TMF  Pavel Mnev, ETH Zürich: TBA
 Jouko Mickelsson, University of Helsinki:
3cocycles, QFT anomalies, and gerbal representationsThe purpose of this contribution is to point out connections between recent ideas about the gerbes and gerbal representations (as higher categorical extension of representation theory) and the old discussion in quantum field theory on commutator anomalies, gauge group extensions, and 3cocycles. The unifying concept is the classical obstruction theory for group extensions as explained in the monograph S. MacLane: Homology.
(Slides)  Dmitry Roytenberg, University of Nijmegen / Utrecht University:
Courant algebroids and Poisson brackets in (1+1)dimensional field theory
The structure of a Courant algebroid is intimately related to both the string geometry of a manifold and the Poisson geometry of its loop space. The latter link is more or less straightforward, the former –much more intriguing.  Urs Schreiber, Utrecht University:
Higher quantomorphism groups on nplectic higher stacks
nPlectic geometry is an interpretation of themultisymplectic description of ndimensional field theory in terms ofhigher algebra/higher geometry. Chris L. Rogers has proposed a definition of Poisson Linfinity algebras over nplectic manifolds. In the talk I give a simple definition of quantomorphism ngroups over nplectic cohesive infinitystacks. Then I discuss that they integrate these Linfinity algebras in the case that the infinitystack is just a smooth manifold, and hence generalize them to the case that it is not. I end by indicating how for n=2 and n=3 the construction subsumes the higher gauge coupling behaviour of the open type II string and the open membrane.  Danny Stevenson, University of Glasgow:
Classifying theory for parametrized simplicial groups
I will describe a classifying theory for parametrized simplicial groups, i.e. simplicial group objects in a suitable category of spaces over a fixed base space, in terms of a certain universal cocycle.  Christian Voigt, University of Glasgow:
The string group and vertex algebras
I shall discuss a tentative realization of the string 2group using unitary vertex superalgebras and unitary full field algebras. This includes a categorified analogue of the Clifford algebra and its spinor representation, and I will explain carefully the analogy to the situation for the spin group.(work in progress)  Tilmann Wurzbacher, RuhrUniversität Bochum:
Dirac operators on loop spaces ?!
We recall the Sigmamodel derivation of the classical indextheorem on a Spin manifold to motivate the quest for a Dirac operator on a loop space and its hypothetical relation to elliptic genera and cohmology via its rotation equivariant index. We then review work of several people (including the speaker) on the construction of Dirac operators on loop spaces and the ensuing problems in Spin geometry of loop spaces/String geometry of manifolds.  Marco Zambon, Universidad Autonoma de Madrid, ICMAT:
Homotopy moment maps
The notion of moment map is central in symplectic geometry, where thefunctions on the symplectic manifold (the “observables”) form a Lie algebra. We extend this notion to higher differential forms, defining ahomotopy moment map to be an $L_{\infty}$algebra morphism into the observables. We give a cohomological interpretation (which provides a natural notion of equivalence), show that certain equivariant cocycles induce homotopy moment maps, and discuss obstructions. This is joint work in progress with Chris L. Rogers (Göttingen) and Yael Fregier (MIT).
Organisers

 Catherine Meusburger,
Department Mathematik, FriedrichAlexander Universität ErlangenNürnberg,
catherine.meusburger@math.unierlangen.de  Thomas Nikolaus,
Fakultät für Mathematik, Universität Regensburg,
thomas1.nikolaus@mathematik.uniregensburg.de  Ulrich Pennig,
Mathematisches Institut, Westfälische WilhelmsUniversität Münster,
u.pennig@unimuenster.de  Christoph Schweigert,
Fachbereich Mathematik, Universität Hamburg,
christoph.schweigert@unihamburg.de  Christoph Wockel,
Fachbereich Mathematik, Universität Hamburg,
Christoph.Wockel@math.unihamburg.de
 Catherine Meusburger,
Travel and Location
The workshop will take place in Erlangen, which is a university town in the southeast of Germany in the region of Franconia. It is easy to reach by a combination of air and train travel. The conference venue is the Department of Mathematics, University of ErlangenNürnberg, Cauerstraße 11, 91058 Erlangen. (Map, Campus Map ) The talks will take place in the lecture theatre Hörsaal 13 on the first floor.
Support
This workshop is an activity of the Research Network String Geometry and the Emerging Fields Project Quantum Geometry and funded by the University of ErlangenNuremberg via its Emerging Fields Initiative.