Semi-Homogeneous Sheaves and Twisted Derived Categories

We produce twisted derived equivalences between torsors under abelian varieties and their moduli spaces of simple semi-homogeneous sheaves. We also establish the natural converse to this result and show that a large class of twisted derived equivalences, including all derived equivalences, between torsors arise in this way. As corollaries, we obtain partial extensions of the usual derived equivalence criterion for abelian varieties established by Orlov and Polishchuk.