Symmetries, Conserved Charges and (Black) Holes in Two Dimensional String Theory

Two dimensional string theory is known to have an infinite dimensional symmetry, both in the continuum formalism as well as in the matrix model formalism. We develop a systematic procedure for computing the conserved charges associated with these symmetries for any configuration of D-branes in the continuum description. We express these conserved charges in terms of the boundary state associated with the D-brane, and also in terms of the asymptotic field configurations produced by this D-brane. Comparison of the conserved charges computed in the continuum description with those computed in the matrix model description facilitates identification of the states between these two formalisms. Using this we put constraints on the continuum description of the hole states in the matrix model, and matrix model description of the black holes solutions of the continuum theory. We also discuss possible generalization of the construction of the conserved charges to the case of D-branes in critical string theory.