Berlin 2024 – wissenschaftliches Programm
Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe
O: Fachverband Oberflächenphysik
O 108: Electronic Structure Theory II
O 108.8: Vortrag
Freitag, 22. März 2024, 12:15–12:30, MA 043
Phaseless auxiliary field quantum Monte Carlo with projector-augmented wave method for solids — Amir Taheridehkordi1, Martin Schlipf2, Zoran Sukurma1, •Moritz Humer1, and Georg Kresse1,2 — 1University of Vienna, Faculty of Physics and Center for Computational Materials Physics, Austria — 2VASP Software GmbH, Vienna, Austria
In this talk, we present our phaseless auxiliary field quantum Monte Carlo (ph-AFQMC) implementation using the plane-wave based projector augmented wave method. We showcase the accuracy and the feasibility of its application to solids. The AFQMC groundstate wavefunction is represented as an ensemble of Slater determinants placed in fluctuating auxiliary fields. This is achieved by transforming the two-body component of the many-body Hamiltonian into an effective one-body potential through the Hubbard Stratonovich transformation. Our implementation is numerically verified by consistent correlation energies from the primitive-cell sampling and the corresponding supercell calculations. We compare the equation of state of diamond and the correlation energies for a range of prototypical solid materials to conventional deterministic quantum-chemistry methods. A down-sampling technique along with natural orbitals accelerates the convergence with respect to the number of orbitals and crystal momentum points. Additionally, we demonstrate that our implementation is competitive in terms of accuracy and computational cost for dense crystal momentum point meshes compared to a well-established coupled-cluster singles-doubles with perturbative triples approach.
Keywords: Monte Carlo methods; Condensed matter physics; Vienna ab initio simulation package (VASP); Projector augmented wave method; Quantum chemistry