Alternative similarity renormalization group generators in nuclear structure calculations

Abstract

The similarity renormalization group (SRG) has been successfully applied to soften interactions for ab initio nuclear calculations. In almost all practical applications in nuclear physics, an SRG generator with the kinetic energy operator is used. With this choice, a fast convergence of many-body calculations can be achieved, but at the same time substantial three-body interactions are induced even if one starts from a purely two-nucleon (NN) Hamiltonian. Three-nucleon (3N) interactions can be handled by modern many-body methods. However, it has been observed that when including initial chiral 3N forces in the Hamiltonian, the SRG transformations induce a non-negligible four-nucleon interaction that cannot be currently included in the calculations for technical reasons. Consequently, it is essential to investigate alternative SRG generators that might suppress the induction of many-body forces while at the same time might preserve the good convergence. In this work we test two alternative generators with operators of block structure in the harmonic oscillator basis. In the no-core shell model calculations for 3H, 4He and 6Li with chiral NN force, we demonstrate that their performances appear quite promising.

Version accepted for publication in Phys. Rev. C

References in corpus (17)

• Chiral effective field theory and nuclear forces
• Similarity Renormalization Group for Nucleon-Nucleon Interactions
• Structure and rotations of the Hoyle state
• Evolution of shell structure in neutron-rich calcium isotopes
• Evolution of Nuclear Many-Body Forces with the Similarity Renormalization Group
• In-Medium Similarity Renormalization Group with Chiral Two- Plus Three-Nucleon Interactions
• Unified ab initio approach to bound and unbound states: no-core shell model with continuum and its application to 7He
• Nuclear Structure in the Framework of the Unitary Correlation Operator Method
• Convergence in the no-core shell model with low-momentum two-nucleon interactions
• Corrections to nuclear energies and radii in finite oscillator spaces
• Evolving Nuclear Many-Body Forces with the Similarity Renormalization Group
• Universal properties of infrared oscillator basis extrapolations
• Momentum space evolution of chiral three-nucleon forces
• Elastic proton scattering of medium mass nuclei from coupled-cluster theory
• Operator Evolution via the Similarity Renormalization Group I: The Deuteron
• Block Diagonalization using SRG Flow Equations
• Decoupling of Spurious Deep Bound States with the Similarity Renormalization Group