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Recently developed neural network-based \emph{ab-initio} solutions (Pfau et. al arxiv:1909.02487v2) for finding ground states of fermionic systems can generate state-of-the-art results on a broad class of systems. In this work, we improve…

Chemical Physics · Physics 2021-03-26 Max Wilson , Nicholas Gao , Filip Wudarski , Eleanor Rieffel , Norm M. Tubman

We present a simulation algorithm for Hamiltonian fermion lattice models. A guiding trial wave function is adaptively optimized during Monte Carlo evolution. We apply the method to the two dimensional Gross-Neveu model and analyze systematc…

High Energy Physics - Lattice · Physics 2009-11-07 Matteo Beccaria , Antonio Moro

Treating the fermionic ground state problem as a constrained stochastic optimization problem, a formalism for fermionic quantum Monte Carlo is developed that makes no reference to a trial wavefunction. Exchange symmetry is enforced by…

Strongly Correlated Electrons · Physics 2020-10-14 Michael Hutcheon

We propose a new Monte Carlo algorithm for the numerical study of general lattice models in Hamiltonian form. The algorithm is based on an initial Ansatz for the ground state wave function depending on a set of free parameters which are…

Statistical Mechanics · Physics 2009-10-31 Matteo Beccaria

We develop a quantum Monte Carlo method to estimate the ground-state energy of a fermionic many-particle system in the configuration-interaction shell model approach. The fermionic sign problem is circumvented by using a guiding wave…

Nuclear Theory · Physics 2015-06-15 Abhishek Mukherjee , Y. Alhassid

We study a Hamiltonian lattice version of the two-dimensional Wess-Zumino model. Preliminary results obtained by Quantum Monte Carlo with a many-parameter guiding wave function are presented. We analyze the pattern of supersymmetry breaking…

High Energy Physics - Lattice · Physics 2015-06-25 Matteo Beccaria , Massimo Campostrini , Alessandra Feo

We formulate a quantum Monte Carlo (QMC) method for calculating the ground state of many-boson systems. The method is based on a field-theoretical approach, and is closely related to existing fermion auxiliary-field QMC methods which are…

Computational Physics · Physics 2009-11-10 Wirawan Purwanto , Shiwei Zhang

We employ constrained path Auxiliary Field Quantum Monte Carlo (AFQMC) in the pursuit of studying physical nuclear systems using a lattice formalism. Since AFQMC has been widely used in the study of condensed-matter systems such as the…

Nuclear Theory · Physics 2024-07-16 Ryan Curry , Jayani Dissanayake , Stefano Gandolfi , Alexandros Gezerlis

We introduce a method that combines the power of both the lattice Green function Monte Carlo (LGFMC) with the auxiliary field techniques (AFQMC), and allows us to compute exact ground state properties of the Hubbard model for U<~ 4t on…

Strongly Correlated Electrons · Physics 2015-06-03 Sandro Sorella

We determine the equation of state of stoichiometric FeO employing the diffusion Monte Carlo method. The fermionic nodes are fixed to those of a wave function having the form of a single Slater determinant. The calculated ambient pressure…

Materials Science · Physics 2008-10-29 Jindrich Kolorenc , Lubos Mitas

We present in detail two variants of the lattice Monte Carlo method aimed at tackling systems in external trapping potentials: a uniform-lattice approach with hard-wall boundary conditions, and a non-uniform Gauss-Hermite lattice approach.…

Quantum Gases · Physics 2016-09-20 Casey E. Berger , Joaquín E. Drut , William J. Porter

A self-contained and tutorial presentation of the diffusion Monte Carlo method for determining the ground state energy and wave function of quantum systems is provided. First, the theoretical basis of the method is derived and then a…

Computational Physics · Physics 2009-10-30 Ioan Kosztin , Byron Faber , Klaus Schulten

We develop a general numerical method to study the zero temperature properties of strongly correlated electron models on large lattices. The technique, which resembles Green's Function Monte Carlo, projects the ground state component from a…

Strongly Correlated Electrons · Physics 2009-10-31 C. Stephen Hellberg , Efstratios Manousakis

In this work we present a novel quantum Monte-Carlo method for fermions, based on an exact decomposition of the Boltzmann operator $exp(-\beta H)$. It can be seen as a synthesis of several related methods. It has the advantage that it is…

Strongly Correlated Electrons · Physics 2009-10-31 S. Rombouts , K. Heyde , N. Jachowicz

We study the ground states of lattice Hamiltonians that are invariant under permutations, in the limit where the number of lattice sites, N -> \infty. For spin systems, these are product states, a fact that follows directly from the quantum…

Quantum Physics · Physics 2013-09-24 Christina V. Kraus , Maciej Lewenstein , J. Ignacio Cirac

Quantum Monte Carlo (QMC) is a stochastic method which has been particularly successful for ground-state electronic structure calculations but mostly unexplored for the computation of excited-state energies. Here, we show that, within a…

Chemical Physics · Physics 2018-08-09 Anthony Scemama , Anouar Benali , Denis Jacquemin , Michel Caffarel , Pierre-François Loos

Compact and accurate wave functions can be constructed by quantum Monte Carlo methods. Typically, these wave functions consist of a sum of a small number of Slater determinants multiplied by a Jastrow factor. In this paper we study the…

Condensed Matter · Physics 2009-10-30 Chien-Jung Huang , C. J. Umrigar , M. P. Nightingale

The development of Monte Carlo algorithms for generating gauge field configurations with dynamical fermions and methods for extracting the most information from ensembles are summarised.

High Energy Physics - Lattice · Physics 2009-11-07 Mike Peardon

Quantum Monte Carlo (QMC) methods represent a powerful family of computational techniques for tackling complex quantum many-body problems and performing calculations of stationary state properties. QMC is among the most accurate and…

Materials Science · Physics 2025-01-08 Alfonso Annarelli , Dario Alfè , Andrea Zen

We present a simple approach to the fixed phase method in Quantum Monte Carlo. This applies to electrons in molecules and electron gas and is straightforwardly extended to the Schr\"odinger equation with magnetic field.

Computational Physics · Physics 2018-02-01 F. Delyon , B. Bernu