Challenges in the description of the atomic nucleus: Unification and interdisciplinarity

Nuclear physics, in general, and theoretical nuclear physics, in particular, have provided the physics community at large, among other things, with the paradigm of spontaneous symmetry breaking phenomena in finite many-body systems. The study of the associated mechanisms of symmetry restoration has shed light on the microscopic structure of the corresponding condensates, in particular on the superfluid phase, allowing to study Cooper pair tunnelling into superfluid nuclei (related to the Josephson effect), in terms of individual quantum states and reaching, in doing so, a new milestone: that of unifying structure and reactions, these last processes being found at the basis of the formulation of quantum mechanics (probability interpretation, Born). In the process, nuclear physicists have extended the validity of BCS theory of superconductivity to the single Cooper pair situation, let alone discovering unexpected mechanism to break gauge invariance. The insight obtained from pair transfer research is likely to have important consequences in the study of double charge exchange processes, and thus in the determination of the nuclear matrix element associated with neutrinoless double beta decay, eventually providing an important test of the Standard Model. Time, thus, seems ripe for nuclear theorists to take centre stage, backed by a wealth of experimental information and by their interdisciplinary capacity to connect basic physical concepts across the borders. With the help of these elements they can aim at fully revealing the many facets of their femtometer many-body system, from vacuum zero point fluctuations to new exotic modes of nuclear excitations and of their interweaving, resulting in powerful effective field theories. Unless. Unless they are not able to free themselves from words like ab initio or fundamental, and to adapt a relax attitude concerning Skyrme, tensor, etc., forces, as well as regarding the quest for “the” Hamiltonian