The "Dual" Variables Of Yang-Mills Theory And Local Gauge Invariant Variables

After adding auxiliary fields and integrating out the original variables, the Yang-Mills action can be expressed in terms of local gauge invariant variables. This method reproduces the known solution of the two dimensional $SU(N)$ theory. In more than two dimensions the action splits into a topological part and a part proportional to $\alpha_s$. We demonstrate the procedure for $SU(2)$ in three dimensions where we reproduce a gravity-like theory. We discuss the four dimensional case as well. We use a cubic expression in the fields as a space-time metric to obtain a covariant Lagrangian. We also show how the four-dimensional $SU(2)$ theory can be expressed in terms of a local action with six degrees of freedom only.Comment: 34pp, LaTeX, Corrections in reference

On Duality Rotations in Light-Like Noncommutative Electromagnetism

We study electric-magnetic duality rotations for noncommutative electromagnetism (NCEM). We express NCEM as a nonlinear commutative U(1) gauge theory and show that it is self-dual when the noncommutativity parameter \theta is light-like (e.g. \theta^{0i}=\theta^{1i}). This implies, in the slowly varying field approximation, self-duality of NCEM to all orders in \theta.Comment: Talk given at Euroconference on Brane New World and Noncommutative Geometry, Villa Gualino, Torino, Italy, 2-7 Oct 2000. 8 pages, LaTe