Constrained coupled-cluster computations yield negative-parity rotational bands
Abstract
Many deformed nuclei exhibit low-lying rotational bands with negative parity. In mean-field calculations, such bands follow from symmetry restoration when the variational solution spontaneously breaks parity. However, they can also be computed in cases where the breaking of parity is not spontaneous but rather enforced by an octupole constraint. In this paper, we extend these techniques to coupled-cluster computations. We introduce octupole-constrained coupled-cluster theory, which explicitly breaks the parity of the correlated intrinsic state and restores parity and angular momentum as good quantum numbers by projection after variation. We perform coupled-cluster singles-and-doubles (CCSD) computations for 20Ne using two- and three-nucleon forces from chiral effective field theory. The energies of the positive-parity ground-state rotational band are close to data and depend only weakly on the constrained octupole moment and the Hartree--Fock reference. In contrast, the energies of the negative-parity rotational band are more sensitive to these auxiliary quantities.
Related
- A Hybrid Brownian Dynamics-kinetic Monte Carlo Framework for Coupled Magnetic and Rotational Dynamics of Nanoparticles
- Constrained estimation of rotational invariants of the cumulant expansion (RICE) for rapid tensor-valued diffusion MRI
- Constraining Effective Viscosity in the Intracluster Medium via the Thermal Sunyaev-Zeldovich Effect -- Predictions from the SLOW Constrained Coma Cluster Simulations
- Model-constrained nanoscale 3D cathodoluminescence reconstruction of InGaN LEDs via coupled electron–photon transport
- Sub-kJ/mol Precision at Practical Cost for Molecular Solids through Local Coupled Cluster Approaches
BibTeX
@misc{hagen2026constrained,
title = {{Constrained coupled-cluster computations yield negative-parity rotational bands}},
author = {Gaute Hagen and Benjamin Bally and Thomas Papenbrock},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.13449},
eprint = {2610.13449},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.13449},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Constrained coupled-cluster computations yield negative-parity rotational bands
AU - Gaute Hagen
AU - Benjamin Bally
AU - Thomas Papenbrock
PY - 2026
DA - 2026/10/09
PB - arXiv
DO - 10.48550/arxiv.2610.13449
UR - https://arxiv.org/abs/2610.13449
AB - Many deformed nuclei exhibit low-lying rotational bands with negative parity. In mean-field calculations, such bands follow from symmetry restoration when the variational solution spontaneously breaks parity. However, they can also be computed in cases where the breaking of parity is not spontaneous but rather enforced by an octupole constraint. In this paper, we extend these techniques to coupled-cluster computations. We introduce octupole-constrained coupled-cluster theory, which explicitly breaks the parity of the correlated intrinsic state and restores parity and angular momentum as good quantum numbers by projection after variation. We perform coupled-cluster singles-and-doubles (CCSD) computations for ^20Ne using two- and three-nucleon forces from chiral effective field theory. The energies of the positive-parity ground-state rotational band are close to data and depend only weakly on the constrained octupole moment and the Hartree--Fock reference. In contrast, the energies of the negative-parity rotational band are more sensitive to these auxiliary quantities.
ER -