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All-electron Fixed-node Diffusion Monte Carlo (FN-DMC) calculations for the nonrelativistic ground-state energy of the water molecule at equilibrium geometry are presented. The determinantal part of the trial wavefunction is obtained from a…

Chemical Physics · Physics 2016-05-25 Michel Caffarel , Thomas Applencourt , Emmanuel Giner , Anthony Scemama

The diffusion Monte Carlo (DMC), auxiliary field quantum Monte Carlo (AFQMC), and equation-of-motion coupled cluster (EOM-CC) methods are used to calculate the electron binding energy (EBE) of the non-valence anion state of a model…

Chemical Physics · Physics 2021-02-03 Shiv Upadhyay , Amanda Dumi , James Shee , Kenneth D. Jordan

We present high-accuracy correlated calculations of small Si$_x$H$_y$ molecular systems both in the ground and excited states. We employ quantum Monte Carlo (QMC) together with a variety of many-body wave function approaches based on basis…

Chemical Physics · Physics 2020-10-21 Guangming Wang , Abdulgani Annaberdiyev , Lubos Mitas

We report diffusion Monte Carlo (DMC) calculations on MgO in the rock-salt and CsCl structures. The calculations are based on Hartree-Fock pseudopotentials, with the single-particle orbitals entering the correlated wave function being…

Strongly Correlated Electrons · Physics 2016-08-16 D. Alfè , M. Alfredsson , J. Brodholt , M. J. Gillan M. D. Towler , R. J. Needs

The VB-QMC method is presented in this chapter. It consists of using in quantum Monte Carlo (QMC) approaches with a wave function expressed as a usually short expansion of classical Valence-Bond (VB) structures supplemented by a Jastrow…

Chemical Physics · Physics 2022-08-01 Slavko Radenković , Dominik Domin , Julien Toulouse , Benoît Braïda

Quantum Monte Carlo (QMC) techniques are used to calculate the one-body density matrix and excitation energies for the valence electrons of bulk silicon. The one-body density matrix and energies are obtained from a Slater-Jastrow wave…

Condensed Matter · Physics 2009-10-31 P. R. C. Kent , Randolph Q. Hood , M. D. Towler , R. J. Needs , G. Rajagopal

Accurate determination of electronic properties of correlated oxides remains a significant challenge for computational theory. Traditional Hubbard-corrected density functional theory (DFT+U) frequently encounters limitations in precisely…

Materials Science · Physics 2024-03-19 Hyeondeok Shin , Kevin Gasperich , Tomas Rojas , Anh T. Ngo , Jaron T. Krogel , Anouar Benali

The band structure of silicon is calculated at the Gamma, X, and L wave vectors using diffusion quantum Monte Carlo methods. Excited states are formed by promoting an electron from the valence band into the conduction band. We obtain good…

Condensed Matter · Physics 2009-10-31 A. J. Williamson , Randolph Q. Hood , R. J. Needs , G. Rajagopal

The ground state of the bipartite $t$-$J$ model must satisfy a specific sign structure, based on which the single-hole and two-hole ground state $Ans\ddot{a}tze$ on honeycomb lattice are constructed and studied by a variational Monte Carlo…

Strongly Correlated Electrons · Physics 2024-06-25 Can Cui , Jing-Yu Zhao , Zheng-Yu Weng

In this work, we report potential energy surfaces (PESs) of the sodium dimer calculated by variational (VMC) and lattice regularized diffusion Monte Carlo (LRDMC). The VMC calculation is accurate for determining the equilibrium distance and…

Chemical Physics · Physics 2020-06-02 Kousuke Nakano , Ryo Maezono , Sandro Sorella

Quantum Monte Carlo (QMC) methods have received considerable attention over the last decades due to their great promise for providing a direct solution to the many-body Schrodinger equation in electronic systems. Thanks to their low scaling…

Chemical Physics · Physics 2013-03-28 M. A. Morales , J. McMinis , B. K. Clark , J. Kim , G. Scuseria

Diffusion Monte Carlo (DMC) is an exact technique to project out the ground state (GS) of a Hamiltonian. Since the GS is always bosonic, in fermionic systems the projection needs to be carried out while imposing anti-symmetric constraints,…

Computational Physics · Physics 2025-01-08 Kousuke Nakano , Sandro Sorella , Dario Alfè , Andrea Zen

Diffusion quantum Monte Carlo calculations with partial and full optimization of the guide function are carried out for the dissociation of the FeS molecule. For the first time, quantum Monte Carlo orbital optimization for transition metal…

Chemical Physics · Physics 2017-07-31 Kaveh Haghighi Mood , Arne Lüchow

We report a study of the electronic dissociation energy of the water dimer using quantum Monte Carlo (QMC) techniques. We have performed variational quantum Monte Carlo (VMC) and diffusion quantum Monte Carlo (DMC) calculations of the…

Other Condensed Matter · Physics 2009-11-13 I. G. Gurtubay , R. J. Needs

Variational and diffusion quantum Monte Carlo (VMC and DMC) methods with Slater-Jastrow-backflow trial wave functions are used to study the spin-polarized three-dimensional uniform electron fluid. We report ground state VMC and DMC energies…

Strongly Correlated Electrons · Physics 2025-11-11 Sam Azadi , N. D. Drummond , Sam. M. Vinko

A paramount goal in the field of nuclear physics is to unify ab-initio treatments of bound and unbound states. The position-space quantum Monte Carlo (QMC) methods have a long history of successful bound state calculations in light systems…

Nuclear Theory · Physics 2023-08-29 Abraham R. Flores , Kenneth M. Nollett

We make a systematical diffusion Monte Carlo (DMC) calculation for all ground state baryons in two confinement scenarios, the pairwise confinement and the three-body flux-tube confinement. With the baryons as an example, we illustrate a…

High Energy Physics - Phenomenology · Physics 2023-03-29 Yao Ma , Lu Meng , Yan-Ke Chen , Shi-Lin Zhu

Quantum Monte Carlo (QMC) methods are some of the most accurate methods for simulating correlated electronic systems. We investigate the compatibility, strengths and weaknesses of two such methods, namely, diffusion Monte Carlo (DMC) and…

Computational Physics · Physics 2020-10-14 Fionn D. Malone , Anouar Benali , Miguel A. Morales , Michel Caffarel , P. R. C. Kent , Luke Shulenburger

We have applied the diffusion quantum Monte Carlo (DMC) method to calculate the cohesive energy and the structural parameters of the binary oxides CaO, SrO, BaO, Sc2O3, Y2O3 and La2O3. The aim of our calculations is to systematically…

Materials Science · Physics 2016-08-24 Juan A. Santana , Jaron T. Krogel , Paul R. C. Kent , Fernando A. Reboredo

Quantum Monte Carlo approaches such as the diffusion Monte Carlo (DMC) method are among the most accurate many-body methods for extended systems. Their scaling makes them well suited for defect calculations in solids. We review the various…

Materials Science · Physics 2014-04-23 William D. Parker , John W. Wilkins , Richard G. Hennig