Extrapolation uncertainties in the importance-truncated No-Core Shell Model

Abstract

We report on Li-6 calculations performed with the IT-NCSM and compare them to full NCSM calculations. We employ the Entem and Machleidt chiral two-body N3LO interaction (regulated at 500 MeV/c), which has been modified to a phase-shift equivalent potential by the similarity renormalization group (SRG) procedure. We investigate the dependence of the procedure on the technique employed to extrapolate to the complete Nmax space, the harmonic oscillator energy, and investigate the dependence on the momentum-decoupling scale (λ) used in the SRG. We also investigate the use of one or several reference states from which the truncated basis is constructed. We find that the uncertainties generated from various extrapolating functions used to extrapolate to the complete Nmax space increase as Nmax increases. The extrapolation uncertainties range from a few keV for the smallest Nmax spaces to about 50 keV for the largest Nmax spaces. We note that the difference between extrapolated IT-NCSM and NCSM ground-state energies, however, can be as large as a 100-250 keV depending on the chosen harmonic oscillator energy. We also present the extrapolation of IT-NCSM results to Nmax infinity and compare these to similarly extrapolated full NCSM results.

22 pages, 12 figures

References in corpus (32)

• Accurate Charge-Dependent Nucleon-Nucleon Potential at Fourth Order of Chiral Perturbation Theory
• Quantum Monte Carlo calculations of nuclei with A \leq 7
• Quantum Monte Carlo Calculations of Light Nuclei
• Three-Nucleon Forces from Chiral Effective Field Theory
• Properties of ${}^{12}$C in the {\it ab initio} nuclear shell-model
• Model-independent low momentum nucleon interaction from phase shift equivalence
• From low-momentum interactions to nuclear structure
• Similarity Renormalization Group for Nucleon-Nucleon Interactions
• Quantum Monte Carlo calculations of A=8 nuclei
• Recent developments in no-core shell-model calculations
• Structure of A=10-13 nuclei with two- plus three-nucleon interactions from chiral effective field theory
• Quantum Monte Carlo calculations of $A=9,10$ nuclei
• Similarity-Transformed Chiral NN+3N Interactions for the Ab Initio Description of 12-C and 16-O
• Few-nucleon systems in translationally invariant harmonic oscillator basis
• Evolution of Nuclear Many-Body Forces with the Similarity Renormalization Group
• Importance Truncation for Large-Scale Configuration Interaction Approaches
• Medium-mass nuclei from chiral nucleon-nucleon interactions
• Corrections to nuclear energies and radii in finite oscillator spaces
• Convergence properties of {\itshape ab initio} calculations of light nuclei in a harmonic oscillator basis
• Evolving Nuclear Many-Body Forces with the Similarity Renormalization Group
• Ab initio many-body calculations of nucleon scattering on 4He, 7Li, 7Be, 12C and 16O
• Towards a Model-Independent Low Momentum Nucleon-Nucleon Interaction
• Ab initio many-body calculations of deuteron-4He scattering and 6Li states
• Nuclear structure with accurate chiral perturbation theory nucleon-nucleon potential: Application to 6Li and 10B
• Ab-initio shell model with a core
• Shell-model calculations for the three-nucleon system
• Ab initio nuclear structure simulations: the speculative ${}^{14}$F nucleus
• Solutions of the Faddeev-Yakubovsky equations for the four nucleons scattering states
• Ground State Wave Functions in the Hyperspherical Formalism for Nuclei with A > 4
• Comment on "Ab Initio study of 40-Ca with an importance-truncated no-core shell model"
• Center-of-mass problem in truncated configuration interaction and coupled-cluster calculations
• Reply to Comment on ``Ab Initio Study of 40-Ca with an Importance Truncated No-Core Shell Model''

Cited by in corpus (6)

• Nuclear effective field theory: status and perspectives
• New applications of renormalization group methods in nuclear physics
• Shell Model States in the Continuum
• Nucleon-$\alpha$ Scattering and Resonances in ${}^5$He and ${}^5$Li with JISP16 and Daejeon16 $NN$ interactions
• Large-scale shell-model calculations on the spectroscopy of $N<126$ Pb isotopes
• Non-parametric Bayesian approach to extrapolation problems in configuration interaction methods