Ab-initio Gorkov-Green's function calculations of open-shell nuclei

TL;DR

This paper introduces a new ab-initio Gorkov Green's function method for open-shell nuclei, demonstrating its effectiveness and expanding the range of nuclei accessible to first-principles calculations.

Contribution

It develops and implements a Gorkov Green's function approach for open-shell nuclei using realistic forces, enabling more comprehensive ab-initio studies.

Findings

Good convergence with basis size in Ca44 and Ni74

Accurate ground-state energies and pairing gaps

Extended accessible nuclei from tens to hundreds

Abstract

We present results from a new ab-initio method that uses the self-consistent Gorkov Green's function theory to address truly open-shell systems. The formalism has been recently worked out up to second order and is implemented here in nuclei for the first time on the basis of realistic nuclear forces. We find good convergence of the results with respect to the basis size in Ca44 and Ni74 and discuss quantities of experimental interest including ground-state energies, pairing gaps and particle addition/removal spectroscopy. These results demonstrate that the Gorkov method is a valid alternative to multireference approaches for tackling degenerate or near degenerate quantum systems. In particular, it increases the number of mid-mass nuclei accessible in an ab-initio fashion from a few tens to a few hundreds.