Large-scale ab initio configuration interaction calculations for light nuclei

• Published in: Journal of physics. Conference series Vol. 403; no. 1; pp. 12019 - 10
• Main Authors: Maris, Pieter, Aktulga, H Metin, Caprio, Mark A, Çatalyürek, Ümit V, Ng, Esmond G, Oryspayev, Dossay, Potter, Hugh, Saule, Erik, Sosonkina, Masha, Vary, James P, Yang, Chao, Zhou, Zheng
• Format: Journal Article
• Language: English
• Published: Bristol IOP Publishing 01.01.2012
• Subjects: Configuration interaction; Determinants; Eigenvalues; Mathematical analysis; Mathematical models; NUCLEAR PHYSICS AND RADIATION PHYSICS; Nuclear structure; Nuclei; Physics; Schrodinger equation; Schroedinger equation; Sparse matrices; Sparsity; Strategy; Wave functions; Wavefunctions
• ISSN: 1742-6588; 1742-6596
• DOI: 10.1088/1742-6596/403/1/012019

In ab-initio Configuration Interaction calculations, the nuclear wavefunction is expanded in Slater determinants of single-nucleon wavefunctions and the many-body Schrodinger equation becomes a large sparse matrix problem. The challenge is to reach numerical convergence to within quantified numerical uncertainties for physical observables using finite truncations of the infinite-dimensional basis space. We discuss strategies for constructing and solving the resulting large sparse matrix eigenvalue problems on current multicore computer architectures. Several of these strategies have been implemented in the code MFDn, a hybrid MPI/OpenMP Fortran code for ab-initio nuclear structure calculations that can scale to 100,000 cores and more. Finally, we will conclude with some recent results for 12C including emerging collective phenomena such as rotational band structures using SRG evolved chiral N3LO interactions.