We exhibit a simple class of exactly marginal “double-trace” deformations of two-dimensional conformal field theories (CFTs) which have ${\mathrm{AdS}}_3$ duals, in which the deformation is given by a product of left- and right-moving U(1) currents. In this special case the deformation on ${\mathrm{AdS}}_3$ is generated by a local boundary term in three dimensions, which changes the physics also in the bulk via bulk-boundary propagators. However, the deformation is nonlocal in six dimensions and on the string world sheet, as in generic nonlocal string theories. Because of the simplicity of the deformation we can explicitly make computations in the nonlocal string theory and compare them to CFT computations, and we obtain precise agreement. We discuss the effect of the deformation on closed strings and on D branes. The examples we analyze include a supersymmetry-breaking but exactly marginal “double-trace” deformation, which is dual to a string theory in which no destabilizing tadpoles are generated for moduli nonperturbatively in all couplings, despite the absence of supersymmetry. We explain how this cancellation works on the gravity side in string perturbation theory, and also nonperturbatively at leading order in the deformation parameter. We also discuss possible flat space limits of our construction.

• Received 30 January 2002

DOI:https://doi.org/10.1103/PhysRevD.65.106007