Abstract
Let X be a smooth projective variety. Using the idea of brane actions discovered by Toën, we construct a lax associative action of the operad of stable curves of genus zero on the variety X seen as an object in correspondences in derived stacks. This action encodes the Gromov-Witten theory of X in purely geometrical terms and induces an action on the derived category Qcoh(X) which allows us to recover the formulas for Quantum K-theory of Givental-Lee. This paper is the first step of a larger project. We believe that this action in correspondences encodes the full classical cohomological Gromov-Witten invariants of X. This will appear in a second paper.