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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

The two-dimensional Hubbard model is studied using the variational quantum Monte Carlo technique with Gutzwiller-type variational wave functions. In addition to the simple one-site correlated Gutzwiller wave function, we use a form with…

Strongly Correlated Electrons · Physics 2007-05-23 A. Harju

We describe and discuss a recently proposed quantum Monte Carlo algorithm to compute the ground-state properties of various systems of interacting fermions. In this method, the ground state is projected from an initial wave function by a…

Condensed Matter · Physics 2009-10-28 Shiwei Zhang , J. Carlson , J. E. Gubernatis

We propose a new quantum Monte Carlo algorithm to compute fermion ground-state properties. The ground state is projected from an initial wavefunction by a branching random walk in an over-complete basis space of Slater determinants. By…

Condensed Matter · Physics 2016-08-31 Shiwei Zhang , J. Carlson , J. E. Gubernatis

Quantum Monte Carlo coupled with neural network wavefunctions has shown success in computing ground states of quantum many-body systems. Existing optimization approaches compute the energy by sampling local energy from an explicit…

Computational Physics · Physics 2023-05-29 Xuan Zhang , Shenglong Xu , Shuiwang Ji

We propose a novel wave function partitioning method that integrates deep-learning variational Monte Carlo with ans\"atze based on generalized product functions. This approach effectively separates electronic wave functions (WFs) into…

Chemical Physics · Physics 2025-06-24 Matěj Mezera , Paolo A. Erdman , Zeno Schätzle , P. Bernát Szabó , Frank Noé

Quantum Monte Carlo is an efficient technique for finding the ground-state energy and related properties of small molecules. A major challenge remains in accurate determination of a molecule's geometry, i.e. the optimal location of its…

Computational Physics · Physics 2017-04-12 Jan Vrbik

Diffusion quantum Monte Carlo calculations with partial and full optimization of the guide function are carried out for the dissociation of the FeS molecule. For the first time, quantum Monte Carlo orbital optimization for transition metal…

Chemical Physics · Physics 2017-07-31 Kaveh Haghighi Mood , Arne Lüchow

A compression algorithm is introduced for multi-determinant wave functions which can greatly reduce the number of determinants that need to be evaluated in quantum Monte Carlo calculations. We have devised an algorithm with three levels of…

Computational Physics · Physics 2015-06-17 Gihan L. Weerasinghe , Pablo Lopez Rios , Richard J. Needs

The quantum Monte Carlo algorithm is arguably one of the most powerful computational many-body methods, enabling accurate calculation of many properties in interacting quantum systems. In the presence of the so-called sign problem, the…

Strongly Correlated Electrons · Physics 2018-02-23 Chia-Chen Chang , Miguel A. Morales

The parameter derivative of the expectation value of the energy, $\partial E/\partial p$, is a key ingredient in variational quantum Monte Carlo (VMC) wave function optimization methods. In some cases, a na\"ive Monte Carlo estimate of this…

Computational Physics · Physics 2020-02-25 Shivesh Pathak , Lucas K. Wagner

Neural network quantum states (NQS), incorporating with variational Monte Carlo (VMC) method, are shown to be a promising way to investigate quantum many-body physics. Whereas vanilla VMC methods perform one gradient update per sample, we…

Disordered Systems and Neural Networks · Physics 2022-11-01 Feng Chen , Ming Xue

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

In this work we develop tools that enable the study of non-adiabatic effects with variational and diffusion Monte Carlo methods. We introduce a highly accurate wave function ansatz for electron-ion systems that can involve a combination of…

Chemical Physics · Physics 2014-10-29 Norm M. Tubman , Ilkka Kylänpää , Sharon Hammes-Schiffer , David M. Ceperley

We propose an efficient numerical method, which combines the advantages of recently developed tensor-network based methods and standard trial wave functions, to study the ground state properties of quantum many-body systems. In this…

Strongly Correlated Electrons · Physics 2015-05-22 Olga Sikora , Hsueh-Wen Chang , Chung-Pin Chou , Frank Pollmann , Ying-Jer Kao

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

We present a simple, robust and highly efficient method for optimizing all parameters of many-body wave functions in quantum Monte Carlo calculations, applicable to continuum systems and lattice models. Based on a strong zero-variance…

Other Condensed Matter · Physics 2009-11-11 C. J. Umrigar , Julien Toulouse , Claudia Filippi , S. Sorella , R. G. Hennig

We show how a ground state trial wavefunction of a Fermi liquid can be systematically improved introducing a sequence of renormalized coordinates through an iterative backflow transformation. We apply this scheme to calculate the ground…

Strongly Correlated Electrons · Physics 2015-06-23 Michele Taddei , Michele Ruggeri , Saverio Moroni , Markus Holzmann

A compact yet accurate approach for representing the wave functions of members of the He and Li isoelectronic series is using explicitly correlated wave functions. These wave functions, however, often have nonlinear forms, which make them…

Atomic Physics · Physics 2023-10-03 D. J. Nader , B. M. Rubenstein

We study one-dimensional (1D) and two-dimensional (2D) Helium atoms using a new time-dependent quantum Monte Carlo (TDQMC) method. The TDQMC method employs random walkers, with a separate guiding wave attached to each walker. The ground…

Atomic Physics · Physics 2025-02-07 I. P. Christov