Efficacy of the SU(3) scheme for ab initio large-scale calculations beyond the lightest nuclei

TL;DR

This paper evaluates the LSU3shell implementation of the symmetry-adapted no-core shell model for large-scale ab initio nuclear calculations, demonstrating its computational efficiency, strong scaling, and memory savings in complex nuclei.

Contribution

It introduces and assesses the LSU3shell approach, showcasing its scalability and memory efficiency for ab initio nuclear structure calculations beyond light nuclei.

Findings

Strong-scaling properties with parallel computing

Memory savings in large model spaces

Accurate results compared to complete model space calculations

Abstract

We report on the computational characteristics of ab initio nuclear structure calculations in a symmetry-adapted no-core shell model (SA-NCSM) framework. We examine the computational complexity of the current implementation of the SA-NCSM approach, dubbed LSU3shell, by analyzing ab initio results for 6Li and 12C in large harmonic oscillator model spaces and SU(3)-selected subspaces. We demonstrate LSU3shell's strong-scaling properties achieved with highly-parallel methods for computing the many-body matrix elements. Results compare favorably with complete model space calculations and significant memory savings are achieved in physically important applications. In particular, a well-chosen symmetry-adapted basis affords memory savings in calculations of states with a fixed total angular momentum in large model spaces while exactly preserving translational invariance.