Improving reach and precision of ab initio theory for new physics studies

Modern first-principles (or “ab initio”) many-body simulations make it possible to compute the structure of atomic nuclei from scratch, starting from effective field theories of quantum chomodynamics. Recent developments have extended the reach of these simulations to the heaviest stable isotopes, to higher precision, and to new applications including many studies of fundamental interactions in nuclei. Particularly key in these applications to possible new physics in nuclei is the predictive power of first-principles simulations combined with the possibility to systematically quantify remaining theory uncertainties. I will discuss two applications of ab initio nuclear structure theory to predict nuclear structure effects in new physics studies. In the first, we identify a nuclear structure effect in high-precision isotope shifts in ytterbium due to higher-order contributions from the nuclear charge density, setting bounds on the mass and coupling of a proposed new boson coupling electrons and neutrons. In the second, we provide precise predictions for leading nuclear contributions to electron to muon conversion in nuclei, allowing for improved constraints on proposed theories of charged lepton flavor violation. I will conclude with an outlook on future applications to searches for new physics and the new developments in ab initio nuclear structure theory that will be necessary to tackle these.