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We describe a Monte Carlo procedure which allows sampling of the disjoint configuration spaces associated with crystalline and fluid phases, within a single simulation. The method utilises biased sampling techniques to enhance the…

Statistical Mechanics · Physics 2009-10-31 N. B. Wilding , A. D. Bruce

The Auxiliary Field Diffusion Monte Carlo method has been applied to simulate droplets of 7 and 8 neutrons. Results for realistic nucleon-nucleon interactions, which include tensor, spin--orbit and three--body forces, plus a standard…

Nuclear Theory · Physics 2009-11-10 Francesco Pederiva , A. Sarsa , K. E. Schmidt , S. Fantoni

We propose a Multi-Cell Monte Carlo algorithm, or (MC)^2, for predicting stable phases in chemically complex crystalline systems. Free atomic transfer among cells is achieved via the application of the lever rule, where an assigned molar…

Materials Science · Physics 2018-11-13 Changning Niu , You Rao , Wolfgang Windl , Maryam Ghazisaeidi

The dissociation energies of four transition metal dimers are determined using diffusion Monte Carlo. The Jastrow, CI, and molecular orbital parameters of the wave function are both partially and fully optimized with respect to the…

Chemical Physics · Physics 2019-09-06 Jil Ludovicy , Kaveh Haghighi Mood , Arne Lüchow

We discuss the efficiency of Monte Carlo methods in solving continuum radiative transfer problems. The sampling of the radiation field and convergence of dust temperature calculations in the case of optically thick clouds are both studied.…

Astrophysics · Physics 2009-11-10 M. Juvela

We extend a recently developed method to solve semi-linear PDEs to the case of a degenerated diffusion. Being a pure Monte Carlo method it does not suffer from the so called curse of dimensionality and it can be used to solve problems that…

Probability · Mathematics 2018-05-15 Xavier Warin

We introduce an exact Monte Carlo approach to the statistics of discrete quantum systems which does not rely on the standard fragmentation of the imaginary time, or any small parameter. The method deals with discrete objects, kinks,…

Condensed Matter · Physics 2009-10-28 N. V. Prokof'ev , B. V. Svistunov , I. S. Tupitsyn

Statistical inference for discretely observed jump-diffusion processes is a complex problem which motivates new methodological challenges. Thus existing approaches invariably resort to time-discretisations which inevitably lead to…

Methodology · Statistics 2023-03-02 Flávio B. Gonçalves , Krzysztof G. Łatuszyński , Gareth O. Roberts

The optimization of neural wave functions in variational Monte Carlo crucially relies on a robust convergence criterion. While the energy variance is theoretically a definitive measure, its practical application as a primary convergence…

Quantum Physics · Physics 2025-11-03 Huan-Chen Shi , Er-Liang Cui , Dan Zhou

A new Monte Carlo approach is proposed to investigate the fluid-solid phase transition of the polydisperse system. By using the extended ensemble, a reversible path was constructed to link the monodisperse and corresponding polydisperse…

Soft Condensed Matter · Physics 2008-07-08 Mingcheng Yang , Hongru Ma

Recently Schautz and Flad concluded that the Hellmann-Feynman theorem holds within the fixed-node diffusion quantum Monte Carlo (DMC) method. We show that the Hellmann-Feynman expression is not in general equal to the derivative of the DMC…

Condensed Matter · Physics 2009-10-31 K. C. Huang , R. J. Needs , G. Rajagopal

In molecular simulations, efficient methods for investigating equilibration and slow relaxation in dense systems are crucial yet challenging. This study focuses on the diffusional characteristics of monodisperse hard disk systems at…

Soft Condensed Matter · Physics 2024-10-21 Daigo Mugita , Masaharu Isobe

The diffusion Monte Carlo technique is used to calculate and analyze the excitation spectrum of $^3$He atoms bound to a cluster of $^4$He atoms, by using a previously determined optimum filling of single-fermion orbits with well defined…

Atomic and Molecular Clusters · Physics 2009-11-11 S. Fantoni , R. Guardiola , J. Navarro , A. Zuker

We present a way to include non local potentials in the standard Diffusion Monte Carlo method without using the locality approximation. We define a stochastic projection based on a fixed node effective Hamiltonian, whose lowest energy is an…

Other Condensed Matter · Physics 2009-11-11 Michele Casula

We provide an extension to lattice systems of the reptation quantum Monte Carlo algorithm, originally devised for continuous Hamiltonians. For systems affected by the sign problem, a method to systematically improve upon the so-called…

Other Condensed Matter · Physics 2010-10-26 Giuseppe Carleo , Federico Becca , Saverio Moroni , Stefano Baroni

A Monte Carlo method is presented to evaluate quantum states with many particles moving in the continuum. The scattering state is generated at each time by a Monte Carlo random sampling algorithm. The same calculation are repeated until the…

Nuclear Theory · Physics 2013-06-06 Zhen-Xiang Xu , Chong Qi

In a recent Letter we introduced Hellmann-Feynman operator sampling in diffusion Monte Carlo calculations. Here we derive, by evaluating the second derivative of the total energy, an efficient method for the calculation of the static…

Other Condensed Matter · Physics 2015-05-13 R. Gaudoin , J. M. Pitarke

In the present paper we consider the initial data, external force, viscosity coefficients, and heat conductivity coefficient as random data for the compressible Navier--Stokes--Fourier system. The Monte Carlo method, which is frequently…

Numerical Analysis · Mathematics 2023-04-04 Maria Lukacova -- Medvidova , Bangwei She , Yuhuan Yuan

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

By performing a stochastic dynamic in a space of Slater determinants, the Full Configuration Interaction Quantum Monte Carlo (FCIQMC) method has been able to obtain energies which are essentially free from systematic error to the basis set…

Computational Physics · Physics 2014-10-10 George H. Booth , Deidre Cleland , Ali Alavi , David P. Tew