Type IIA and heterotic string vacua in D=2 Original Research Article

We study type IIA string theory compactified on Calabi–Yau fourfolds and heterotic string theory compactified on Calabi–Yau threefolds times a two-torus. We derive the resulting effective theories which have two spacetime dimensions and preserve four supercharges. The duality between such vacua is established at the level of the effective theory. For type IIA vacua with non-trivial Ramond–Ramond background fluxes a superpotential is generated. We show that for a specific choice of background fluxes and a fourfold which has the structure of a threefold fibred over a sphere the superpotential coincides with the superpotential recently proposed by Taylor and Vafa in compactifications of type IIB string theory on a threefold.