DUALITY SYMMETRIES IN NONLINEAR GAUGE THEORIES

Duality symmetries are discussed for nonlinear gauge theories of (n-1)th rank antisymmetric tensor fields in general even dimensions d=2n. When there are M field strengths and no scalar fields, the duality symmetry groups should be compact. We find conditions on the Lagrangian required by compact duality symmetries and show an example of duality invariant nonlinear theories. We also discuss how to enlarge the duality symmetries to noncompact groups by coupling scalar fields described by nonlinear sigma models.