Ab initio coupled-cluster approach to nuclear structure with modern nucleon-nucleon interactions

TL;DR

This paper applies ab initio coupled-cluster methods with modern nucleon-nucleon interactions to compute properties of various nuclei, demonstrating good agreement with experimental data and analyzing convergence and center-of-mass issues.

Contribution

It introduces a coupled-cluster approach incorporating triples corrections with modern interactions, assessing convergence and the impact of three-nucleon forces in medium-mass nuclei.

Findings

Coupled-cluster with triples corrections binds nuclei within 0.4 MeV per nucleon of data.

Three-nucleon forces are consistent with power counting estimates.

Slow convergence observed with certain potentials and model spaces.

Abstract

We perform coupled-cluster calculations for the doubly magic nuclei 4He, 16O, 40Ca and 48Ca, for neutron-rich isotopes of oxygen and fluorine, and employ "bare" and secondary renormalized nucleon-nucleon interactions. For the nucleon-nucleon interaction from chiral effective field theory at order next-to-next-to-next-to leading order, we find that the coupled-cluster approximation including triples corrections binds nuclei within 0.4 MeV per nucleon compared to data. We employ interactions from a resolution-scale dependent similarity renormalization group transformations and assess the validity of power counting estimates in medium-mass nuclei. We find that the missing contributions due to three-nucleon forces are consistent with these estimates. For the unitary correlator model potential, we find a slow convergence with respect to increasing the size of the model space. For the G-matrix approach, we find a weak dependence of ground-state energies on the starting energy combined with a rather slow convergence with respect to increasing model spaces. We also analyze the center-of-mass problem and present a practical and efficient solution.