Bulletin of the American Physical Society
APS April Meeting 2019
Volume 64, Number 3
Saturday–Tuesday, April 13–16, 2019; Denver, Colorado
Session R14: Theoretical Aspects of Nuclear Structure
1:30 PM–3:18 PM,
Monday, April 15, 2019
Sheraton Room: Plaza Court 3
Sponsoring Unit: DNP
Chair: Maxime Brodeur, University of Notre Dame
Abstract: R14.00009 : Ab-initio wave-function approach to aperiodic helical lattices*
3:06 PM–3:18 PM
(Comenius University, Slovak Academy of Sciences)
Stefan Varga (Slovak Academy of Sciences) is acknowledged for assisting in derivation of the multipole expansion
As a model system, a chain of hydrogen atoms is embedded onto a cylinder and its electronic ground-state is numerically investigated. The resulting helix is periodic in the curved cylindrical space, but the periodicity in the Cartesian space is not guaranteed. Aperiodic helices exist and can be generated by irrational rotations, akin to the Penrose tiling . To address such systems with microscopic precision, integrals of localized functions are calculated in a given supercell, while the Hartree-Fock is formulated in the Fourier space associated to the helical symmetry. Second order perturbative corrections are limited to pair excitations (pair-MP2). The method is thoroughly benchmarked on finite rings against coupled cluster theory . The 1D thermodynamic limit is reached by extrapolation. The issue of a slow (1/R) saturation of the Coulomb field is overcame by approximating the contributions from the tails of the chain, i.e. the far-field, by a fast multipole expansion (FMM) that utilizes merely one-body properties.
 C. Corduneanu, Almost periodic functions (Chelsea Pub. Co, New York, N.Y, 1989)
 M. Motta et. al,Physical Review X 7 (2017), 10.1103/physrevx.7.031059.
*Grant agency of the Slovak Republic is acknowledged for support VEGA 1/0507/17
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