1:30 pm MCP 201
Topological terms, diffeomorphism anomalies and CS theories in fluid dynamics.
The requirement of diffeomorphism symmetry for the target space lead to anomalous commutators for the energy-momentum tensor for sigma models and for fluid dynamics, if certain topological terms are added to the action. We analyze some examples. A topological term is shown to lead to the known effective hydrodynamics of a dense collection of vortices, i.e.,the vortex fluid theory in 2+1 dimensions. This will be related to Wiegmann's work on the vortec fluid in Hall effect and superfluids. Among other points we explore the relationship to Chern-Simons theory and the possibility of a similar vortex fluid in 3+1 dimensions, as well as a fluid of knots and links, with possible extended diffeomorphism algebras.