scholarly journals Tensor-decomposition techniques for ab initio nuclear structure calculations: From chiral nuclear potentials to ground-state energies

2019 ◽  
Vol 99 (3) ◽  
Author(s):  
A. Tichai ◽  
R. Schutski ◽  
G. E. Scuseria ◽  
T. Duguet
Keyword(s):  
Ab Initio ◽  
Nuclear Structure ◽  
Ground State ◽  
Tensor Decomposition ◽  
Decomposition Techniques ◽  
Nuclear Structure Calculations ◽  
Structure Calculations ◽  
Ground State Energies

scholarly journals Accelerating many-nucleon basis generation for high performance computing enabled ab initio nuclear structure studies

2019 ◽  
Vol 33 (3) ◽  
pp. 522-533 ◽  
Author(s):  
Daniel Langr ◽  
Tomáš Dytrych ◽  
Kristina D Launey ◽  
Jerry P Draayer
Keyword(s):  
Ab Initio ◽  
Nuclear Structure ◽  
High Performance ◽  
Model Framework ◽  
Significant Acceleration ◽  
Model Spaces ◽  
Basis Construction ◽  
Nuclear Structure Calculations ◽  
Performance Computing ◽  
Structure Calculations

We present the problem of generating a many-nucleon basis in [Formula: see text]-scheme for ab initio nuclear structure calculations in a symmetry-adapted no-core shell model framework. We first discuss and analyze the basis construction algorithm whose baseline implementation quickly becomes a significant bottleneck for large model spaces and heavier nuclei. The outcomes of this analysis are utilized to propose a new scalable version of the algorithm. Its performance is consequently studied empirically using the Blue Waters supercomputer. The measurements show significant acceleration achieved with over two orders of magnitude speedups realized for larger model spaces.

AB INITIO NUCLEAR STRUCTURE CALCULATIONS OF p-SHELL NUCLEI WITH JISP16

2013 ◽  
Vol 22 (07) ◽  
pp. 1330016 ◽  
Author(s):  
PIETER MARIS ◽  
JAMES P. VARY
Keyword(s):  
Ab Initio ◽  
Magnetic Moments ◽  
Nucleon Nucleon ◽  
Quadrupole Moments ◽  
Nucleon Interaction ◽  
Excitation Energies ◽  
Nucleon Nucleon Interaction ◽  
Nuclear Structure Calculations ◽  
Structure Calculations ◽  
Ground State Energies

We review energies and magnetic moments of p-shell nuclei obtained with the ab initio No-Core Full Configuration (NCFC) approach using the JISP16 realistic nucleon–nucleon interaction. We present calculated ground state energies for all stable p-shell nuclei and selected unstable isotopes, as well as their magnetic moments. We also review excitation energies for narrow resonances of A = 6 to 9 nuclei. We compare our results with experimental data and with other ab initio calculations, where available. We illustrate how the decomposition of total angular momentum into intrinsic spin and orbital components provides insights into the structure of states and relationships among states. We illustrate the challenges of obtaining converged results for radii, quadrupole moments and B(E2) values.

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