Semiclassical cosmological perturbations generated during inflation

Interaction with the environment may induce stochastic semiclassical dynami cs in open quantum systems. In the gravitational context, stress-energy flu ctuations of quantum matter fields give rise to a stochastic behavior in th e spacetime geometry. The Einstein-Langevin equation is a suitable tool to take these effects into account when addressing the backreaction problem in semiclassical gravity. We analyze within this framework the generation of gravitational fluctuations during inflation, which are of great interest fo r large-scale structure formation in cosmology.