Duality Symmetry in the Schwarz - Sen Model ∗

The continuous extension of the discrete duality symmetry of the SchwarzSen model is studied. The corresponding infinitesimal generator Q turns out to be local, gauge invariant and metric independent. Furthermore, Q commutes with all the conformal group generators. We also show that Q is equivalent to the non—local duality transformation generator found in the Hamiltonian formulation of Maxwell theory. We next consider the Batalin– Fradkin–Vilkovisky formalism for the Maxwell theory and demonstrate that requiring a local duality transformation lead us to the Schwarz–Sen formulation. The partition functions are shown to be the same which implies the quantum equivalence of the two approaches.