P-shell nuclei using Similarity Renormalization Group evolved three-nucleon interactions

TL;DR

This paper investigates the use of the Similarity Renormalization Group to evolve three-nucleon interactions for p-shell nuclei, assessing convergence, extrapolation, and energy dependence on the SRG scale in ab initio calculations.

Contribution

It provides benchmark no-core configuration calculations with SRG-evolved interactions, highlighting the importance of consistent evolution and basis truncation effects in nuclear structure.

Findings

Convergence properties depend on SRG resolution scale.

Extrapolation techniques improve energy estimates.

Four-body contributions influence energy calculations.

Abstract

The Similarity Renormalization Group (SRG) is used to soften interactions for ab initio nuclear structure calculations by decoupling low- and high-energy Hamiltonian matrix elements. The substantial contribution of both initial and SRG-induced three-nucleon forces requires their consistent evolution in a three-particle basis space before applying them to larger nuclei. While in principle the evolved Hamiltonians are unitarily equivalent, in practice the need for basis truncation introduces deviations, which must be monitored. Here we present benchmark no-core full configuration calculations with SRG-evolved interactions in p-shell nuclei over a wide range of softening. These calculations are used to assess convergence properties, extrapolation techniques, and the dependence of energies, including four-body contributions, on the SRG resolution scale.