Duality symmetry in the Schwarz-Sen model

The continuous extension of the discrete duality symmetry of the Schwarz-Sen 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 nonlocal 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 leads us to the Schwarz-Sen formulation. The partition functions are shown to be the same, which implies the quantum equivalence of the two approaches. copyright 1997 The American Physical Society