I work at the interface between high-energy physics, string theory and cosmology with particular interest in theories of the early Universe. Recently, I have been studying quantum effects from interacting fields in spacetimes where the rate of expansion accelerates. In the context of inflation, this is the basic theory from which we can calculate deviations from Gaussianity. Various ongoing missions are constraining this fundamental characteristic of primordial perturbations. More speculatively, I have been looking for possible sensitivity to initial conditions through infrared effects. If present, this persistence of memory goes against the standard folklore that inflation is insensitive to initial conditions and it may also provide a natural explanation for the smallness of the measured value of the dark energy today. Finally, I also work on topological defects and their high energy signatures such as gravitational wavebursts from cosmic strings.