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Systematic Comparison and Cross-validation of Fixed-Node Diffusion Monte Carloand Phaseless Auxiliary-Field Quantum Monte Carlo in Solids

ORAL

Abstract

Diffusion Monte Carlo (DMC) and Auxiliary Field Quantum Monte Carlo (AFQMC) can both have their approximations systematically improved by applying successively more accurate trial wavefunctions. In this work we assess the feasibility of determining exact total energies for solid state Hamiltonians by studying primitive cells of four representative
materials, Al, LiF and Carbon-diamond. Specifically, we utilize multideterminant trial wavefunctions generated via selective CI techniques with various sizes of single particle basis. Attention is paid to the rate at which the error decreases as the trial wavefunction includes more determinants and the increase of the basis size. In this way, we are able to compare both DMC and AFQMC on equal terms at identical levels of approximation.
https://doi.org/10.1103/PhysRevB.102.161104

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Presenters

  • Anouar Benali

    Argonne National Laboratory, Computational Science Division, Argonne National Laboratory

Authors

  • Anouar Benali

    Argonne National Laboratory, Computational Science Division, Argonne National Laboratory

  • Fionn Malone

    Lawrence Livermore National Laboratory, Quantum Simulations Group, Lawrence Livermore National Laboratory

  • Miguel A Morales

    Lawrence Livermore National Laboratory, Quantum Simulations Group, Lawrence Livermore National Laboratory

  • Michel Caffarel

    Laboratoire de Chimie et Physique Quantiques, Universite de Toulouse

  • Paul Kent

    Oak Ridge National Lab, Oak Ridge National Laboratory

  • Luke Shulenburger

    Sandia National Laboratories