|
Calendar of Physics Talks Vienna
| Boundary conditions for extended TQFTs and anomalies |
| Speaker: | Alessandro Valentino (MPI Bonn) |
| Abstract: | In this talk I will present recent work together with Domenico Fiorenza on topological quantum field theories(TQFTs) on manifolds with boundaries. Using infinity-category theory, we develop a formalism to relate extended TQFTs with boundary conditions to lower dimensional theories with anomalies, which in turn give rise to projective representations of the mapping class group of closed manifolds. The case of fully extended TQFTs will be discussed as well. |
| Date: | Wed, 18.02.2015 |
| Time: | 15:15 |
| Duration: | 60 min |
| Location: | ESI, Boltzmann lecture hall |
| Contact: | Nils Carqueville |
| Central extensions of mapping class groups from characteristic classes |
| Speaker: | Domenico Fiorenza (Rome I) |
| Abstract: | In 3d topological field theories with nontrivial central charge one replaces 2-dimensional and 3-dimensional manifold by suitable "extended" counterparts, in such a way that the mapping class group of an extended surface is a Z-central extension of the mapping class group of the underlying surface, and the set of extensions of a 3-manifod with prescribed boundary behavior is a Z-torsor. In Segal's celebrated paper on conformal field theory, the extension consist in a "rigging", a solution which is not particularly simple and which is actually quite ad hoc for the 3-dimensional case. Namely, riggings are based on the contractibility of Teichmueller spaces and on the properties of the eta-invariant for 3-manifolds with boundary. On the other hand, Segal suggest that simpler variants of this construction should exist, the essential idea being that of associating functorially to any surface |
| Date: | Wed, 18.02.2015 |
| Time: | 16:30 |
| Duration: | 60 min |
| Location: | ESI, Boltzmann lecture hall |
| Contact: | Nils Carqueville |
|