Speaker
Description
This talk focuses on the application of modern numerical perturbative methods, familiar from collider physics, to the precision frontier of cosmology. To match the accuracy of modern cosmological surveys, theoretical predictions from the Effective Field Theory of Large-Scale Structure (EFTofLSS) must be pushed to the two-loop level, a task for which purely numerical techniques are essential due to the absence of known analytic master integrals. I will present a robust numerical framework for computing these two-loop corrections. Its efficiency for cosmological parameter scans is achieved by decoupling the cosmology dependence from the loop integrations. We ensure the stability of the multi-dimensional Monte Carlo integration by treating UV and IR singularities locally, at the integrand level. The core of the method is to pre-compute a set of universal tensor integrals, which are then combined to produce predictions for any specific cosmology. This framework allows us to compute the renormalized two-loop dark matter power spectrum, which requires 13 counterterms, some necessarily non-local in time. Our work demonstrates a successful application of numerical perturbative techniques to cosmology, enabling precision parameter inference and establishing the foundation for two-loop computations of other observables, like the galaxy power spectrum.
