Coupled-cluster (CC) theory represents an important theoretical tool that we use to solve the quantum many-body problem. CC theory also lends itself to computation in a parallel computing environment. In this paper, we present selected results from ab initio studies of stable and weakly bound nuclei utilizing computational techniques that we employ to solve CC theory. We also outline several perspectives for future research directions in this area.

Computational Science & DiscoveryNov 20, 20086 citations

Bulletin of the American Physical Society

Ab initio Bogoliubov coupled cluster theory

A. Signoracci, G. Hagen, T. Duguet

Published Oct 11, 2014• 0 citations

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Computational Science & DiscoveryNov 20, 20086 citations

m

scheme, which will permit the treatment of doubly open-shell nuclei via the further breaking of SU(2) symmetry associated with angular momentum conservation.Results: Proof-of-principle calculations in an

{N}_{\text{max}}=6

spherical harmonic oscillator basis for

^{16,18}\mathrm{O}

and

^{18}\mathrm{Ne}

in the BCCD approximation are in good agreement with standard coupled cluster results with the same chiral two-nucleon interaction, while

^{20}\mathrm{O}

and

^{20}\mathrm{Mg}

display underbinding relative to experiment. The breaking of U(1) symmetry, monitored by computing the variance associated with the particle-number operator, is relatively constant for all five nuclei, in both the Hartree-Fock-Bogoliubov and BCCD approximations.Conclusions: The newly developed many-body formalism increases the potential span of ab initio calculations based on single-reference coupled cluster techniques tremendously, i.e., potentially to reach several hundred additional midmass nuclei. The new formalism offers a wealth of potential applications and further extensions dedicated to the description of ground and excited states of open-shell nuclei. Short-term goals include the implementation of three-nucleon forces at the normal-ordered two-body level. Midterm extensions include the approximate treatment of triples corrections and the development of the equation-of-motion methodology to treat both excited states and odd nuclei. Long-term extensions include exact restoration of U(1) and SU(2) symmetries.