Open $sd$-shell nuclei from first principles

TL;DR

This paper extends an ab initio method to compute properties of deformed open-shell nuclei, successfully reproducing many experimental observations and demonstrating the emergence of collective phenomena from first principles.

Contribution

It introduces an extension of the coupled-cluster effective interaction method to deformed open-shell nuclei, enabling ab initio calculations of complex nuclear phenomena.

Findings

Good agreement with experimental binding energies and spectra.

Reproduction of rotational bands and electric quadrupole transitions.

Charge radii of neon isotopes are underestimated.

Abstract

We extend the ab initio coupled-cluster effective interaction (CCEI) method to deformed open-shell nuclei with protons and neutrons in the valence space, and compute binding energies and excited states of isotopes of neon and magnesium. We employ a nucleon-nucleon and three-nucleon interaction from chiral effective field theory evolved to a lower cutoff via a similarity renormalization group transformation. We find good agreement with experiment for binding energies and spectra, while charge radii of neon isotopes are underestimated. For the deformed nuclei $^{20}$Ne and $^{24}$Mg we reproduce rotational bands and electric quadrupole transitions within uncertainties estimated from an effective field theory for deformed nuclei, thereby demonstrating that collective phenomena in $sd$-shell nuclei emerge from complex ab initio calculations.