Ab Initio Nuclear Structure Theory with Chiral NN+3N Interactions

Low-energy nuclear theory has entered an era of ab initio nuclear structure and reaction calculations based on QCD. One of the most promising paths from QCD to nuclear observables employs Hamiltonians constructed within chiral effective field theory as starting point for precise ab initio studies. However, the full inclusion of chiral twoplus three-nucleon (NN+3N) interactions in exact and approximate many-body calculations poses a formidable challenge. We discuss recent breakthroughs that allow for ab initio calculations for ground states and spectra of nuclei throughout the pand the lower sd-shell with full 3N interactions using consistent Similarity Renormalization Group (SRG) transformations and the Importance Truncated No-Core Shell Model (IT-NCSM). Moreover, we discuss extensions of these ab initio calculations to heavy nuclei within coupled cluster theory using a normal ordering approximation of the 3N interaction.