BÄCKLUND TRANSFORMATION, LOCAL AND NONLOCAL CONSERVATION LAWS FOR NONLINEAR σ-MODELS ON SYMMETRIC COSET SPACES

Two-dimensional nonlinear σ-models defined on symmetrical coset spaces are considered. The duality symmetry is used to construct a Bäcklund transformation which depends on a continuous parameter γ. Conserved current depending on γ is obtained. Expanding the current in powers of γ around γ = 1, one gets an infinite number of nonlocal conserved currents. A modified form of conserved current depending on γ is also obtained. When this current is expanded in powers of γ or γ⁻¹, one gets two sets of infinite number of local conserved currents.