Eur. Phys. J. A (2021) 57: 135
https://doi.org/10.1140/epja/s10050-021-00437-4

Regular Article –Theoretical Physics

Moving away from singly-magic nuclei with Gorkov Green’s function theory

¹ IRFU, CEA, Université Paris-Saclay, 91191, Gif-sur-Yvette, France
² Department of Physics, University of Surrey, GU2 7XH, Guildford, UK
³ Dipartimento di Fisica, Università degli Studi di Milano, Via Celoria 16, 20133, Milano, Italy
⁴ INFN, Sezione di Milano, Via Celoria 16, 20133, Milano, Italy
⁵ KU Leuven, Institut voor Kern-en Stralingsfysica, 3001, Leuven, Belgium
⁶ TRIUMF, 4004 Westbrook Mall, V6T 2A3, Vancouver, BC, Canada

^a vittorio.soma@cea.fr

Received: 18 September 2020
Accepted: 22 March 2021
Published online: 19 April 2021

Abstract

Ab initio calculations of bulk nuclear properties (ground-state energies, root-mean-square charge radii and charge density distributions) are presented for seven complete isotopic chains around calcium, from argon to chromium. Calculations are performed within the Gorkov self-consistent Green’s function approach at second order and make use of two state-of-the-art two- plus three-nucleon Hamiltonians, + and NNLO. An overall good agreement with available experimental data is found, in particular for differential energies (charge radii) when the former (latter) interaction is employed. Remarkably, neutron magic numbers emerge and evolve following experimental trends. In contrast, pairing gaps are systematically underestimated. General features of the isotopic dependence of charge radii are also reproduced, as well as charge density distributions. A deterioration of the theoretical description is observed for certain nuclei and ascribed to the inefficient account of (static) quadrupole correlations in the present many-body truncation scheme. In order to resolve these limitations, we advocate the extension of the formalism towards incorporating breaking of rotational symmetry or, alternatively, performing a stochastic sampling of the self-energy.