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Variational methods are used to calculate structural and thermodynamical properties of a titrating polyelectrolyte in a discrete representation. The Coulomb interactions are emulated by harmonic repulsive forces, the force constants being…

chem-ph · Physics 2008-02-03 B. Jönsson , M. Ullner , C. Peterson , O. Sommelius , B. Söderberg

We present an efficient method to find minimum energy structures using energy estimates from accurate quantum Monte Carlo calculations. This method involves a stochastic process formed from the stochastic energy estimates from Monte Carlo…

Computational Physics · Physics 2015-05-18 Lucas K. Wagner , Jeffrey C. Grossman

We consider the use in quantum Monte Carlo calculations of two types of valence bond wave functions based on strictly localized active orbitals, namely valence bond self-consistent-field (VBSCF) and breathing-orbital valence bond (BOVB)…

Chemical Physics · Physics 2011-03-14 Benoît Braïda , Julien Toulouse , Michel Caffarel , C. J. Umrigar

A quantum Monte Carlo method combining update of the loop algorithm with the global flip of the world line is proposed as an efficient method to study the magnetization process in an external field, which has been difficult because of…

Statistical Mechanics · Physics 2009-10-31 Hiroaki Onishi , Masamichi Nishino , Naoki Kawashima , Seiji Miyashita

The accurate computation of forces and other energy derivatives has been a long-standing challenge for quantum Monte Carlo methods. A number of technical obstacles contribute to this challenge. We discuss how these obstacles can be removed…

Materials Science · Physics 2023-05-29 Siyuan Chen , Shiwei Zhang

Hamiltonian Monte Carlo (HMC) is an efficient Bayesian sampling method that can make distant proposals in the parameter space by simulating a Hamiltonian dynamical system. Despite its popularity in machine learning and data science, HMC is…

Machine Learning · Statistics 2020-09-02 Ziming Liu , Zheng Zhang

We introduce a general Monte Carlo scheme for achieving atomistic simulations with monoelectronic Hamiltonians including the thermalization of both nuclear and electronic degrees of freedom. The kinetic Monte Carlo algorithm is used to…

Materials Science · Physics 2009-11-07 F. Calvo , F. Spiegelman

Hamiltonian Monte Carlo is a prominent Markov Chain Monte Carlo algorithm, which employs symplectic integrators to sample from high dimensional target distributions in many applications, such as statistical mechanics, Bayesian statistics…

Numerical Analysis · Mathematics 2025-02-13 Geoffrey McGregor , Andy T. S. Wan

Quantum Monte Carlo (QMC) is an advanced simulation methodology for studies of manybody quantum systems. In this review, we focus on the electronic structure QMC, i.e., methods relevant for systems described by the electron-ion…

Other Condensed Matter · Physics 2010-08-16 Michal Bajdich , Lubos Mitas

The behaviour of the one--dimensional random--forced Burgers equation is investigated in the path integral formalism, using a discrete space--time lattice. We show that by means of Monte Carlo methods one may evaluate observables, such as…

High Energy Physics - Lattice · Physics 2009-01-14 P. Düben , D. Homeier , K. Jansen , D. Mesterhazy , G. Münster , C. Urbach

We discuss the methodology of quantum Monte Carlo calculations of the effective mass based on the static self energy, $\Sigma(k,0)$. We then use variational Monte Carlo calculations of $\Sigma(k,0)$ of the homogeneous electron gas at…

Strongly Correlated Electrons · Physics 2023-05-04 Markus Holzmann , Francesco Calcavecchia , David M. Ceperley , Valerio Olevano

A second-order many-body perturbation correction to the relativistic Dirac-Hartree-Fock energy is evaluated stochastically by integrating 13-dimensional products of four-component spinors and Coulomb potentials. The integration in the real…

Quantum Physics · Physics 2022-06-16 J. César Cruz , Jorge Garza , Takeshi Yanai , So Hirata

A method is presented to tackle the sign problem in the simulations of systems having indefinite or complex-valued measures. In general, this new approach is shown to yield statistical errors smaller than the crude Monte Carlo using…

High Energy Physics - Lattice · Physics 2008-11-26 T D Kieu , C J Griffin

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

Quantum Monte Carlo methods are powerful numerical tools to accurately solve the Schr\"odinger equation for nuclear systems, a necessary step to describe the structure and reactions of nuclei and nucleonic matter starting from realistic…

Nuclear Theory · Physics 2020-05-01 Stefano Gandolfi , Diego Lonardoni , Alessandro Lovato , Maria Piarulli

The accuracy and efficiency of ab-initio quantum Monte Carlo (QMC) algorithms benefits greatly from compact variational trial wave functions that accurately reproduce ground state properties of a system. We investigate the possibility of…

Materials Science · Physics 2019-01-30 Shivesh Pathak , Lucas K. Wagner

We present a Monte Carlo numerical investigation of the Hamiltonian Mean Field (HMF) model. We begin by discussing canonical Metropolis Monte Carlo calculations, in order to check the caloric curve of the HMF model and study finite size…

Statistical Mechanics · Physics 2009-11-10 Alessandro Pluchino , Giuseppe Andronico , Andrea Rapisarda

Nuclear physics seeks to describe both bound and unbound states within a unified predictive framework. While coordinate-space Quantum Monte Carlo (QMC) methods have successfully computed bound states for systems with $A \leq 12$, their…

Nuclear Theory · Physics 2025-02-27 Abraham R. Flores , Kenneth M. Nollett , Maria Piarulli

A Monte Carlo algorithm for computing quantum mechanical expectation values of coordinate operators in many body problems is presented. The algorithm, that relies on the forward walking method, fits naturally in a Green's Function Monte…

Condensed Matter · Physics 2009-10-28 J. Casulleras , J. Boronat

The implementation and reliability of a quadratic diffusion Monte Carlo method for the study of ground-state properties of atoms are discussed. We show in the simple yet non-trivial calculation of the binding energy of the Li atom that the…

Condensed Matter · Physics 2009-11-07 A. Sarsa , J. Boronat , J. Casulleras