Structure ofA=7–8 nuclei with two- plus three-nucleon interactions from chiral effective field theory

Abstract

We solve the ab initio no-core shell model (NCSM) in the complete 8 Ω (Nmax = 8) basis for A = 7 and A = 8 nuclei with two-nucleon and three-nucleon interactions derived within chiral effective field theory (EFT). We find that including the chiral EFT three-nucleon interaction in the Hamiltonian improves overall agreement with experimental binding energies, excitation spectra, transitions and electromagnetic moments. We predict states that exhibit sensitivity to including the chiral EFT three-nucleon interaction but are not yet known experimentally.

Symmetry-guided large-scale shell-model theory

“…The typical dimension of a symplectic irrep in the N max = 6 space is on the order of 10 2 as compared to 10 7 for the complete NCSM M -scheme basis. As N max increases the dimension of the J = 0, 2, and 4 Sp(3, R)-scheme model space built on the 0p-0h Sp(3, R) irreps for 12 C grows very slowly and remains a small fraction of the complete model space even when the most dominant 2 Ω 2p-2h Sp(3, R) irreps are included (Fig.…”

“…Several ab initio nuclear-theory approaches have been recently advanced, including Green's function Monte Carlo (GFMC) [6,7], no-core shell model (NCSM) [8][9][10][11][12] together with NCSM with a core [13] and importance truncation NCSM [14], coupledcluster method (CC) [15,16], lattice effective field theory [17], in-medium SRG [18,19], symmetryadapted no-core shell model (SA-NCSM) [20], Monte Carlo NCSM [21], and self-consistent Green's function [22]. Ab initio approaches build upon a 'first principles' foundation.…”

Extension of coupled-cluster theory with a noniterative treatment of connected triply excited clusters to three-body Hamiltonians

“…In order to make accurate QCD-based predictions using ab initio many-body methods employing Hamiltonians constructed within chiral EFT, the inclusion of three-nucleon (3N) forces is inevitable [6,7], affecting various important nuclear properties, such as binding and excitation energies [8][9][10][11][12][13][14]. While some many-body approaches, such as the no-core shell model (NCSM) [15][16][17][18][19][20] and its importance-truncated (IT) extension [18,21,22] or coupled-cluster (CC) theory [23][24][25][26][27][28][29][30] truncated at the singly and doubly excited clusters (CCSD) [22,[31][32][33][34][35][36][37][38][39][40][41][42] have already been extended to the explicit treatment of 3N interactions and were successfully applied to light and medium-mass nuclei [10,11,14,43,44], other approaches remain to be generalized to the explicit 3N case.…”

Collective Modes in Light Nuclei from First Principles

“…-Major progress in the development of realistic inter-nucleon interactions along with the utilization of massively parallel computing resources [1][2][3] have placed ab initio approaches [4][5][6][7][8][9][10][11][12][13][14] at the frontier of nuclear structure explorations. The ultimate goal of ab initio studies is to establish a link between underlying principles of quantum chromodynamics (quark/gluon considerations) and observed properties of atomic nuclei, including their structure and related reactions.…”