W-Geometry and isomonodromic deformations

M. Olshanetsky

Abstract: We consider new type of times in the isomonodromy preserving equations coming from deformations of $W$-structures of the basic spectral curve. $W_k$-structure is the generalized complex structure defined by $(-k+1,1)$-differentials, while the $W_2$-structure is the standard complex structure since $(-1,1)$-differentials are the Beltrami differentials. We derive these equations via symplectic reduction from the Chern-Simons theory. Solutions of the moment constraints equations are the Lax operators of the corresponding linear problem. These equations for $k>2$ are nonlinear and the Lax operators and the Hamiltonians can be found only perturbatively. On the quantum level this theory corresponds to the generalized KZB equations with higher order Casimirs.
As an example, we consider $W_3$ theory on $P^1$ with $n$ marked points (the analog of the SL(3) Schlesinger system).