Perturbative treatment of nonlocal chiral interactions in auxiliary-field diffusion Monte Carlo calculations

Abstract: Nuclear many-body systems, ranging from nuclei to neutron stars, are some of the most interesting physical phenomena in our universe, and Quantum Monte Carlo (QMC) approaches are among the most accurate many-body methods currently available to study them. In recent decades, interactions derived from chiral effective field theory (EFT) have been widely adopted in the study of nuclear many-body systems. One drawback of the QMC approach is the requirement that the nuclear interactions need to be local, whereas chiral EFT interactions usually contain nonlocalities. In this work, we leverage the capability of computing second-order perturbative corrections to the ground-state energy in order to develop a self-consistent approach to including nonlocal operators in QMC calculations. We investigate both the deuteron and the neutron-matter equation of state in order to show the robustness of our technique, and pave the way for future QMC calculations at higher orders in the EFT, where nonlocal operators cannot be avoided.