Atomic nuclei are among the most complex quantum many-body systems, with deeply intertwined single-particle and collective degrees of freedom. Despite the tremendous progress made towards a microscopic description of nuclear structure, providing a universal, predictive and precise description of all nuclei remains a great challenge.

The nuclear structure method which I will present describes the nucleus as a system of relativistic nucleons interacting via effective meson exchange. Starting from a mean-field approximation, this approach applies nuclear field theory in order to account for inter-nucleon correlations emerging from the coupling between single particles and collective vibrations of the nucleus. Such a framework thus allows a connection between the nuclear scales and can provide a consistent description of ground and excited states in a wide range of nuclei.

I will discuss recent developments and applications of this approach to stable and exotic nuclei of various masses in the context of topics that will be investigated by the Facility for Rare Isotope Beams (FRIB). Emphasis will be put on the description of nuclear charge-exchange modes, such as Gamow-Teller, which govern beta decay and r-process nucleosynthesis.