Variational procedure for nuclear shell-model calculations and energy-variance extrapolation

Abstract

We discuss a variational calculation for nuclear shell-model calculations and propose a new procedure for the energy-variance extrapolation (EVE) method using a sequence of the approximated wave functions obtained by the variational calculation. The wave functions are described as linear combinations of the parity, angular-momentum projected Slater determinants, the energy of which is minimized by the conjugate gradient method obeying the variational principle. The EVE generally works well using the wave functions, but we found some difficult cases where the EVE gives a poor estimation. We discuss the origin of the poor estimation concerning shape coexistence. We found that the appropriate reordering of the Slater determinants allows us to overcome this difficulty and to reduce the uncertainty of the extrapolation.

6 pages, 5 figures, submitted to Physical Review C

References in corpus (14)

• Effective interaction for pf-shell nuclei
• Path-Integral Renormalization Group Method for Numerical Study of Strongly Correlated Electron Systems
• Chaotic wave functions and exponential convergence of low-lying energy eigenvalues
• Novel Extrapolation Method in the Monte Carlo Shell Model
• An extrapolation method for shell model calculations
• A High-Performance Algorithm to Calculate Spin- and Parity-Dependent Nuclear Level Densities
• Factorization of shell-model ground-states
• Extrapolation Method for the No-Core Shell Model
• Density Matrix Renormalization Group and the Nuclear Shell Model
• Precise estimation of shell model energy by second order extrapolation method
• Improved basis selection for the Projected Configuration Interaction method applied to heavy nuclei
• New variational Monte Carlo method with an energy variance extrapolation for large-scale shell-model calculations
• Extrapolation method in shell model calculations with deformed basis
• Benchmark calculation of no-core Monte Carlo shell model in light nuclei

Cited by in corpus (11)

• Microscopic Clustering in Light Nuclei
• Quantum Phase Transition in the Shape of Zr isotopes
• Advanced density matrix renormalization group method for nuclear structure calculations
• Shape coexistence in even-even nuclei: A theoretical overview
• Importance-Truncated Large-Scale Shell Model
• Variational approach with the superposition of the symmetry-restored quasi-particle vacua for nuclear shell-model calculations
• Large-scale shell-model calculations for unnatural-parity high-spin states in neutron-rich Cr and Fe isotopes
• Recent progress in configuration-interaction shell model
• Mitigating algorithmic errors in quantum optimization through energy extrapolation
• Effect of residual many-body forces due to the evolution in the in-medium similarity renormalization group method
• Many-body calculations with Deuteron based single-particle bases and their associated natural orbits