Toward Scalable Many-Body Calculations for Nuclear Open Quantum Systems using the Gamow Shell Model

Abstract

Drip-line nuclei have very different properties from those of the valley of stability, as they are weakly bound and resonant. Therefore, the models devised for stable nuclei can no longer be applied therein. Hence, a new theoretical tool, the Gamow Shell Model (GSM), has been developed to study the many-body states occurring at the limits of the nuclear chart. GSM is a configuration interaction model based on the use of the so-called Berggren basis, which contains bound, resonant and scattering states, so that inter-nucleon correlations are fully taken into account and the asymptotes of extended many-body wave functions are precisely handled. However, large complex symmetric matrices must be diagonalized in this framework, therefore the use of very powerful parallel machines is needed therein. In order to fully take advantage of their power, a 2D partitioning scheme using hybrid MPI/OpenMP parallelization has been developed in our GSM code. The specificities of the 2D partitioning scheme in the GSM framework will be described and illustrated with numerical examples. It will then be shown that the introduction of this scheme in the GSM code greatly enhances its capabilities.

23 pages; 5 figures; accepted in Computer Physics Communications, in press

References in corpus (9)

• Shell Model in the Complex Energy Plane
• Factorization in large-scale many-body calculations
• Can tetraneutron be a narrow resonance?
• Quantified Gamow Shell Model interaction for $psd$-shell nuclei
• Accelerating Nuclear Configuration Interaction Calculations through a Preconditioned Block Iterative Eigensolver
• {\it Ab initio} nuclear structure - the large sparse matrix eigenvalue problem
• Continuum Coupling and Single-Nucleon Overlap Integrals
• Single-particle and collective motion in unbound deformed ${}^{39}\text{Mg}$
• A simple and efficient numerical scheme to integrate non-local potentials

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• Ab initio descriptions of $A=16$ mirror nuclei with resonance and continuum coupling
• Complex valence-space effective operators for observables: the Gamow-Teller transition
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• Gamow shell model predictions for six-proton unbound nucleus ${}^{20}$Si
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