Convergence in the no-core shell model with low-momentum two-nucleon interactions

Abstract

The convergence of no-core shell model (NCSM) calculations using renormalization group evolved low-momentum two-nucleon interactions is studied for light nuclei up to Li-7. Because no additional transformation was used in applying the NCSM framework, the energy calculations satisfy the variational principle for a given Hamiltonian. Dramatic improvements in convergence are found as the cutoffs are lowered. The renormalization group equations are truncated at two-body interactions, so the evolution is only approximately unitary and converged energies for A > 2 vary with the cutoff. This approximation is systematic, however, and for useful cutoff ranges the energy variation is comparable to natural-size truncation errors inherent from the initial chiral effective field theory potential.

27 pages, 24 figures, improved discussion on running of energies

References in corpus (6)

• Coupled-cluster theory for three-body Hamiltonians
• 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
• The Unitary Correlation Operator Method from a Similarity Renormalization Group Perspective
• Decoupling in the Similarity Renormalization Group for Nucleon-Nucleon Forces

Cited by in corpus (4)

• Unitary Correlation Operator Method and Similarity Renormalization Group: Connections and Differences
• Block Diagonalization using SRG Flow Equations
• Decoupling in the Similarity Renormalization Group for Nucleon-Nucleon Forces
• Low-momentum interactions in three- and four-nucleon scattering