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In this note, variational Monte Carlo method based on neural quantum states for spin systems is reviewed. Using a neural network as the wave function allows for a more generalized expression of various types of interactions, including…

Strongly Correlated Electrons · Physics 2024-06-04 Yuntai Song

We introduce a neural network-based approach for modeling wave functions that satisfy Bose-Einstein statistics. Applying this model to small $^4He_N$ clusters (with N ranging from 2 to 14 atoms), we accurately predict ground state energies,…

Atomic and Molecular Clusters · Physics 2023-12-20 William Freitas , S. A. Vitiello

Fixed-node diffusion Monte Carlo (DMC) is a stochastic algorithm for finding the lowest energy many-fermion wave function with the same nodal surface as a chosen trial function. It has proved itself among the most accurate methods available…

Condensed Matter · Physics 2009-10-31 W. M. C. Foulkes , Randolph Q. Hood , R. J. Needs

We show that recently developed quantum Monte Carlo methods, which provide accurate vertical transition energies for single excitations, also successfully treat double excitations. We study the double excitations in medium-sized molecules,…

The variational quantum eigensolver (VQE) algorithm, designed to calculate the energy of molecular ground states on near-term quantum computers, requires specification of symmetries that describe the system, e.g. spin state and number of…

Quantum Physics · Physics 2020-06-18 Gabriel Greene-Diniz , David Muñoz Ramo

We discuss an alternative accurate Monte Carlo method to calculate the ground-state energy and related quantities for Laughlin states of the fractional quantum Hall effect in a disk geometry. This alternative approach allows us to obtain…

Mesoscale and Nanoscale Physics · Physics 2009-11-13 Orion Ciftja , Carlos Wexler

We derive many-body single- and multi-reference wave functions for quantum Monte Carlo of periodic systems with an anti-symmetric portion that explicitly integrates over the Brillouin zone of one-particle Bloch states. The wave functions…

Strongly Correlated Electrons · Physics 2023-09-28 Lubos Mitas

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

The variational Monte Carlo method is applied to investigate the ground state energy of the lithium atom and its ions up to Z=10 in the presence of an external magnetic field regime with {\gamma}=0 ~ 100 a.u. Our calculations are based on…

Atomic Physics · Physics 2016-02-24 S. B. Doma , M. O. Shaker , A. M. Farag , F. N. El-Gammal

Calculations of highly excited and delocalized molecular vibrational states are computationally challenging tasks, which strongly depends on the choice of coordinates for describing vibrational motions. We introduce a new method that…

We consider a new formulation of the stochastic coupled cluster method in terms of the similarity transformed Hamiltonian. We show that improvement in the granularity with which the wavefunction is represented results in a reduction in the…

Chemical Physics · Physics 2016-02-02 Ruth S. T. Franklin , James S. Spencer , Alberto Zoccante , Alex J. W. Thom

We develop a quantum embedding method that enables accurate and efficient treatment of interactions between molecules and an environment, while explicitly including many-body correlations. The molecule is composed of classical nuclei and…

Chemical Physics · Physics 2023-03-30 Matej Ditte , Matteo Barborini , Leonardo Medrano Sandonas , Alexandre Tkatchenko

The ground and excited state calculations at key geometries, such as the Frank-Condon (FC) and the conical intersection (CI) geometries, are essential for understanding photophysical properties. To compute these geometries on noisy…

Quantum Physics · Physics 2023-01-02 Shigeki Gocho , Hajime Nakamura , Shu Kanno , Qi Gao , Takao Kobayashi , Taichi Inagaki , Miho Hatanaka

We have studied the spin-polarized three-dimensional homogeneous electron gas using the diffusion quantum Monte Carlo method, with trial wave functions including backflow and three-body correlations in the Jastrow factor, and we have used…

Strongly Correlated Electrons · Physics 2013-08-28 G G Spink , R J Needs , N D Drummond

We present an improved formalism for quantum Monte Carlo calculations of energy derivatives and properties (e.g. the interatomic forces), with a multideterminant Jastrow-Slater function. As a function of the number $N_e$ of Slater…

Chemical Physics · Physics 2017-06-26 Roland Assaraf , Saverio Moroni , Claudia Filippi

We report all-electron and pseudopotential calculations of the ground-stateenergies of the neutral Ne atom and the Ne+ ion using the variational and diffusion quantum Monte Carlo (DMC) methods. We investigate different levels of…

Materials Science · Physics 2008-01-03 N. D. Drummond , P. Lopez Rios , A. Ma , J. R. Trail , G. Spink , M. D. Towler , R. J. Needs

We perform a comprehensive analysis of the quantum-enhanced Monte Carlo method [Nature, 619, 282-287 (2023)], aimed at identifying the optimal working point of the algorithm. We observe an optimal mixing Hamiltonian strength and analyze the…

Quantum Physics · Physics 2025-07-01 Johannes Christmann , Petr Ivashkov , Mattia Chiurco , Guglielmo Mazzola

The first three dynamic multipole polarizabilities for the ground state of hydrogen, helium, hydride ion, and positronium hydride PsH have been computed using the variational Monte Carlo (VMC) method and explicitly correlated wave…

Atomic Physics · Physics 2009-11-06 Massimo Mella , Dario Bressanini , Gabriele Morosi

We present a comprehensive benchmark study of the adsorption energy of a single water molecule on the (001) LiH surface using periodic coupled cluster and quantum Monte Carlo theories. We benchmark and compare different implementations of…

We develop a variational Monte Carlo (VMC) method for electron-phonon coupled systems. The VMC method has been extensively used for investigating strongly correlated electrons over the last decades. However, its applications to…

Strongly Correlated Electrons · Physics 2014-06-02 Takahiro Ohgoe , Masatoshi Imada