Constructing regularized cosmic propagators

We present a new scheme for the general computation of cosmic propagators that allow to interpolate between standard perturbative results at low k and their expected large-k resummed behavior. This scheme is applicable to any multipoint propagator and allows the matching of perturbative low-k calculations to any number of loops to their large-k behavior, and can potentially be applied in case of nonstandard cosmological scenarios such as those with non-Gaussian initial conditions. The validity of our proposal is checked against previous prescriptions and measurements in numerical simulations showing a remarkably good agreement. Such a generic prescription for multipoint propagators provides the necessary building blocks for the computation of polyspectra in the context of the so-called Gamma expansion introduced by F. Bernardeau, M. Crocce, and R. ScoccimarroPhys. Rev. D 78, 103521 (2008).. As a concrete application we present a consistent calculation of the matter bispectrum at one-loop order.