Space-time duality and superduality

We introduce a new class of duality symmetries amongst quantum held theorie s. The new class is based upon global space-rime symmetries, such as Poinca re invariance and supersymmetry, in the same way as the existing duality tr ansformations are based on global internal symmetries. We illustrate these new duality transformations by dualizing several scalar and spin-half field theories in 1+1 space-time dimensions, involving non-supersymmetric as wel l as (1,1) and (2,2) supersymmetric models, For (2, 2) models the new duali ty transformations can interchange chiral and twisted chiral multiplets. (C ) 1999 Elsevier Science B.V.