Electromagnetic and Exotic Moments in Nuclear DFT

TL;DR

The paper investigates electromagnetic observables in nuclei using nuclear density functional theory, focusing on charge and current distributions and their multipole moments. It develops self-consistent, symmetry-restored nuclear wave functions to compute spectroscopic moments and compares them with experimental data, assessing the accuracy of the DFT approach. It discusses potential improvements in magnetic dipole operators via two-body meson-exchange currents and explores exotic symmetry-breaking moments to illuminate nuances of nuclear interactions. The supplemental material provides detailed derivations of angular-momentum projection and related operators, enhancing transparency and reproducibility for future studies of nuclear electromagnetic structure.

Abstract

Electromagnetic interactions serve as essential probes for studying and testing our understanding of the atomic nucleus, as they reveal emergent properties across the nuclear chart. We analyse their corresponding observables, which relate to charge and current distributions in nuclei expressed through their multipole components. We focus on theoretical results obtained within nuclear density functional theory (DFT) to derive self-consistent, symmetry-restored nuclear wave functions along with their spectroscopic multipole moments. We demonstrate how these compare with experimental data. We also discuss potential improvements in the formulation of magnetic dipole operators by including two-body meson-exchange contributions. Discussions of exotic symmetry-breaking moments emphasise their importance for understanding fine details of fundamental nuclear interactions. Detailed derivations are provided in the accompanying Supplemental Material.

Figures (1)

• Figure 1: Residuals (upper panels), $\Omega_{\text{the}}-\Omega_{\text{exp}}$ (in $\mu_{N}b$), or relative residuals, $(\Omega_{\text{the}}-\Omega_{\text{exp}})/|\Omega_{\text{exp}}|$, of magnetic octupole moments determined with respect to the collective strong coupling model, left panels, weak coupling model, middle panels, and nuclear DFT, right panels. For the left and middle panels, the model results and experimental data are taken from Reference BOFOS2024101672. For the right panels, the experimental data are shown in Table\ref{['tab:MO']}, and the preliminary theoretical results are taken from Reference (deG25b). In all panels, data for $^{173}$Yb are not shown because their values exceed the panels' scales. In panels (c) and (f), the data for $^{25}$Mg and $^{71}$Ga are omitted as the nuclear-DFT results are unavailable. In panel (f), data for $^{45}$Sc and $^{197}$Au are not displayed because their values exceed the scale of the panel, owing to the smallness of $|\Omega_{\text{exp}}|$.