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Extended TQFT's and Quantum Gravity
Mathematical Physics Seminar| Speaker: | Jeffrey Morton, University of Western Ontario |
| Location: | 2112 MSB |
| Start time: | Fri, Mar 14 2008, 3:10PM |
Extended Topological Quantum Field Theories (ETQFTs) are a tool from quantum topology which give invariants for manifolds with corners, related to the Dijkgraaf-Witten models. I will discuss ETQFT's and how they can be used to describe topological field theories coupled to codimension-2 matter. For example, Ponzano-Regge gravity in 3 dimensions coupled to point particles having mass and spin, or BF theory in 4 dimensions coupled to strings or networks. I will show how the Extended TQFT picture can be described in terms of gauge theory and a "higher-algebraic" version of a sum-over-histories, and how this relates to these examples.