Ab initio coupled-cluster and configuration interaction calculations for 16-O using V_UCOM

Abstract

Using the ground-state energy of 16-O obtained with the realistic V_UCOM interaction as a test case, we present a comprehensive comparison of different configuration interaction (CI) and coupled-cluster (CC) methods, analyzing the intrinsic advantages and limitations of each of the approaches. In particular, we use the importance-truncated (IT) CI and no-core shell model (NCSM) schemes with up to 4-particle-4-hole (4p4h) excitations as well as the size extensive CC methods with a complete treatment of one- and two-body clusters (CCSD) and a non-iterative treatment of connected three-body clusters via the completely renormalized correction to the CCSD energy defining the CR-CC(2,3) approach. We discuss the impact of the center-of-mass contaminations, the choice of the single-particle basis, and size-extensivity on the resulting energies. When the IT-CI and IT-NCSM methods include the 4p4h excitations and when the CC calculations include the 1p1h, 2p2h, and 3p3h clusters, as in the CR-CC(2,3) approach, we observe an excellent agreement among the different methodologies. This shows that despite their individual limitations, the IT-CI, IT-NCSM, and CC methods can provide precise and consistent ab initio nuclear structure predictions. Furthermore, the IT-CI, IT-NCSM, and CC ground-state energy values obtained with 16-O are in good agreement with the experimental value, proving that the V_UCOM two-body interaction allows for a realistic description of binding energies for heavier nuclei and that all of the methods used in this study account for most of the relevant particle correlation effects.

20 pages, 4 figures, 1 table (v2: extended version in response to referees' comments)

References in corpus (7)

• Structure of A=10-13 nuclei with two- plus three-nucleon interactions from chiral effective field theory
• Matrix Elements and Few-Body Calculations within the Unitary Correlation Operator Method
• Benchmark calculations for 3H, 4He, 16O and 40Ca with ab-initio coupled-cluster theory
• Effective operators within the ab initio no-core shell model
• Unitary Correlation Operator Method and Similarity Renormalization Group: Connections and Differences
• Converging sequences in the ab initio no-core shell model
• The Unitary Correlation Operator Method from a Similarity Renormalization Group Perspective

Cited by in corpus (3)

• Importance Truncation for Large-Scale Configuration Interaction Approaches
• Pairing in the Framework of the Unitary Correlation Operator Method (UCOM): Hartree-Fock-Bogoliubov Calculations
• Center-of-mass problem in truncated configuration interaction and coupled-cluster calculations