Nuclear collectivity and the harmonic spectrum of two-body correlations

Abstract: High-energy nuclear collisions have opened a new experimental method to reveal collective behavior in nuclear ground states through the lens of many-body correlations of nucleons. Using ab initio lattice and variational calculations of $^{20}$Ne and $^{16}$O, we study how emergent phenomena such as deformation or clustering can be identified in these systems from the dependence of their two-body density distributions on the relative azimuthal angle of nucleon pairs. A harmonic analysis of the correlation functions reveals in particular a dominant quadrupole component in $^{20}$Ne, consistent with a bowling-pin picture, and a prominent triangular modulation in $^{16}$O, possibly indicative of alpha-cluster correlations. Given that such structures can be accurately identified in high-energy collider experiments, these findings open a new paradigm for analyzing emergent collective behavior in atomic nuclei, relating their intrinsic shapes to the harmonic spectrum of microscopic correlations.