Perturbative treatment of non-local operators in an ab initio context*

In recent years, there has been a dramatic improvement in our ability to investigate the nuclear many-body problem, due to the availability of several different powerful many-body techniques and sophisticated nuclear interactions derived from chiral effective field theory (EFT). Our work on the nuclear many-body problem focuses on using the ab initio Quantum Monte Carlo family of approaches. We recently developed a new formalism to calculate the second-order perturbative correction in a Diffusion Monte Carlo context, and investigated the perturbativeness of chiral EFT interactions in a many-body context. I will present on recent work extending this formalism to realistic nuclear interactions in the auxiliary field diffusion Monte Carlo many body technique, as well as for non-local operators for both the deuteron and neutron matter.