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This topical review describes the methodology of continuum variational and diffusion quantum Monte Carlo calculations. These stochastic methods are based on many-body wave functions and are capable of achieving very high accuracy. The…

Materials Science · Physics 2010-02-11 R. J. Needs , M. D. Towler , N. D. Drummond , P. Lopez Rios

By variational Monte-Carlo method developed Ceperley et al. for the simulation of fermi systems in macroscopic confining potential well we simulate various spin ground states of the coulomb clusters with 2,3 and 4 particles in a broad…

Condensed Matter · Physics 2007-05-23 B. Abdullaev , A. D. Kidisyuk , M. M. Musakhanov

We explore different ways of incorporating accurate trial wave functions into free projection auxiliary field quantum Monte Carlo (fp-AFQMC). Trial states employed include coupled cluster singles and doubles, multi-Slater, and symmetry…

Chemical Physics · Physics 2021-04-15 Ankit Mahajan , Sandeep Sharma

By explicitly including fractionally ionic contributions to the polarizability of a many-component system we are able to significantly improve on previous atom-wise many-body van der Waals approaches with essentially no extra numerical…

Chemical Physics · Physics 2017-03-28 Tim Gould , Sébastien Lebègue , János G. Ángyán , Tomáš Bučko

In this work we set up a model Hamiltonian to study the excited state quantum dynamics of 1,1-difluoroethylene, a molecule that has equivalent atoms exchanged by a torsional symmetry operation leading to equivalent minima on the potential…

Chemical Physics · Physics 2023-06-07 Sandra Gómez , Nadja Singer , Leticia González , Graham Worth

We develop a Monte Carlo wave function algorithm for the quantum linear Boltzmann equation, a Markovian master equation describing the quantum motion of a test particle interacting with the particles of an environmental background gas. The…

Quantum Physics · Physics 2010-09-28 Marc Busse , Piotr Pietrulewicz , Heinz-Peter Breuer , Klaus Hornberger

An effective optimization strategy has been developed to construct highly accurate bound state wave functions in various three-body systems. Our procedure appears to be very effective for computations of weakly bound states and various…

Atomic Physics · Physics 2014-11-21 Alexei M. Frolov , David M. Wardlaw

We study the structural and several quantum properties of three-dimensional bosonic cluster interacting through van der Waals potential at large scattering length. We use Faddeev-type decomposition of the many-body wave function which…

Quantum Gases · Physics 2019-02-04 M. L. Lekala , B. Chakrabarti , S. K. Haldar , R. Roy , G. J. Rampho

A more reasonable trial ground state wave function is constructed for the relative motion of an interacting two-fermion system in a 1D harmonic potential. At the boundaries both the wave function and its first derivative are continuous and…

Quantum Gases · Physics 2017-04-06 Yanxia Liu , Jun Ye , Yuanyuan Li , Yunbo Zhang

We apply a path integral variational approach to obtain analytical expressions for condensate wave functions of an ultracold, interacting trapped Bose gases. As in many recent experiments, the particles are confined in a 1D or 3D harmonic…

Quantum Gases · Physics 2014-03-07 Wattana Ratismith , Holger Hauptmann , Walter T. Strunz

We describe and systematically analyze new implementations of the Projection Operator Imaginary Time Spectral Evolution (POITSE) method for the Monte Carlo evaluation of excited state energies. The POITSE method involves the computation of…

Computational Physics · Physics 2007-05-23 Patrick Huang , Alexandra Viel , K. Birgitta Whaley

A method is presented for the optimization of one-body and inhomogeneous two-body terms in correlated electronic wave functions of Jastrow-Slater type. The most general form of inhomogeneous correlation term which is compatible with crystal…

Strongly Correlated Electrons · Physics 2009-11-07 David Prendergast , David Bevan , Stephen Fahy

Accurate numerical solution of the five-body Schrodinger equation is effected via variational Monte Carlo. The spectrum is assumed to exhibit a narrow resonance with strangeness S=+1. A fully antisymmetrized and pair-correlated five-quark…

Nuclear Theory · Physics 2014-11-18 Mark W. Paris

We present a systematically-improvable approach to core excitations in variational Monte Carlo. Building on recent work in excited-state-specific Monte Carlo, we show how a straightforward protocol, starting from a quantum chemistry guess,…

Chemical Physics · Physics 2020-10-28 Scott M. Garner , Eric Neuscamman

We propose a method to calculate wave functions and energies not only of the ground state but also of low-lying excited states using a deep neural network and the unsupervised machine learning technique. For systems composed of identical…

Computational Physics · Physics 2023-12-07 Tomoya Naito , Hisashi Naito , Koji Hashimoto

We propose an optimized algorithm for the numerical simulation of two-time correlation functions by means of stochastic wave functions. As a first application, we investigate the two-time correlation function of a nonlinear optical…

Quantum Physics · Physics 2015-06-26 Timo Felbinger , Martin Wilkens

There are multiple cluster randomised trial designs that vary in when the clusters cross between control and intervention states, when observations are made within clusters, and how many observations are made at that time point. Identifying…

Methodology · Statistics 2023-07-20 Samuel I. Watson , Alan Girling , Karla Hemming

Neural-network wave functions in Variational Monte Carlo (VMC) have achieved great success in accurately representing both ground and excited states. However, achieving sufficient numerical accuracy in state overlaps requires increasing the…

Machine Learning · Computer Science 2026-05-28 Nicholas Gao , Till Grutschus , Frank Noé , Stephan Günnemann

We study a system of interacting electrons on a one-dimensional quantum ring using exact diagonalization and the variational quantum Monte Carlo method. We examine the accuracy of the Slater-Jastrow -type many-body wave function and compare…

Mesoscale and Nanoscale Physics · Physics 2007-05-23 S. S. Gylfadottir , A. Harju , T. Jouttenus , C. Webb

We present a new method for realizing the adiabatic connection approach in density functional theory, which is based on combining accurate variational quantum Monte Carlo calculations with a constrained optimization of the ground state…

Materials Science · Physics 2015-06-25 Maziar Nekovee , W. M. C. Foulkes , A. J. Williamson , G. Rajagopal , R. J. Needs