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We formulate a convergent sequence for the energy gap estimation in the worldline quantum Monte Carlo method. The ambiguity left in the conventional gap calculation for quantum systems is eliminated. Our estimation will be unbiased in the…

Statistical Mechanics · Physics 2015-09-02 Hidemaro Suwa , Synge Todo

In this paper we present Classical Trajectory Monte Carlo (CTMC) calculations for single and multiple electron ionization of Argon atoms and ions in the threshold region. We are able to recover the Wannier exponents a for the power-law…

Atomic Physics · Physics 2014-11-18 F. Sattin , K. Katsonis

A great many observables seen in intermediate energy heavy ion collisions can be explained on the basis of statistical equilibrium. Calculations based on statistical equilibrium can be implemented in microcanonical ensemble (energy and…

Nuclear Theory · Physics 2009-11-10 C. B. Das , S. Das Gupta , W. G. Lynch , A. Z. Mekjian , M. B. Tsang

A simple Monte Carlo procedure is described for simulating the multiple scattering and absorption of electrons with the incident energy in the range 1-50 keV moving through a slab of uniformly distributed material of given atomic number,…

Materials Science · Physics 2007-05-23 Nima Ghal-eh , Mohammad Farhad Rahimi , Mehrnoush Manouchehri

Many body trial wave functions are the key ingredient for accurate Quantum Monte Carlo estimates of total electronic energies in many electron systems. In the Coupled Electron-Ion Monte Carlo method, the accuracy of the trial function must…

Computational Physics · Physics 2009-11-13 Carlo Pierleoni , Kris T. Delaney , Miguel A. Morales , David M. Ceperley , Markus Holzmann

Quantum Monte Carlo methods are used to calculate various ground state properties of charged bosons in two dimensions, throughout the whole density range where the fluid phase is stable. Wigner crystallization is predicted at $r_s\simeq…

Condensed Matter · Physics 2018-05-01 S. De Palo , S. Conti , S. Moroni

We report variational and diffusion Quantum Monte Carlo ground-state energies of the three-dimensional electron gas using a model periodic Coulomb interaction and backflow corrections for N=54, 102, 178, and 226 electrons. We remove…

Materials Science · Physics 2010-01-28 I. G. Gurtubay , R. Gaudoin , J. M. Pitarke

We propose a quantum Monte Carlo approach to solve the ground state many-body Schrodinger equation for the electronic ground state. The method combines optimization from variational Monte Carlo and propagation from auxiliary field quantum…

Computational Physics · Physics 2023-04-21 Yixiao Chen , Linfeng Zhang , Weinan E , Roberto Car

The magnetic properties of Mn-doped ZnO semi-conductor have been investigated using the Monte Carlo method within the Ising model. The temperature dependences of the spontaneous magnetization, specific heat and magnetic susceptibility have…

Materials Science · Physics 2015-05-28 L. B Drissi , A. Benyoussef , E. H Saidi , M. Bousmina

Quantum Monte Carlo (QMC) methods can very accurately compute ground state properties of quantum systems. We applied these methods to a system of boson hard spheres to get exact, infinite system size results for the ground state at several…

Computational Physics · Physics 2016-09-08 Mark Dewing

With recent developments in simulating nonadiabatic systems to high accuracy, it has become possible to determine how much energy is attributed to nuclear quantum effects beyond zero-point energy. In this work we calculate the…

Chemical Physics · Physics 2016-08-23 Yubo Yang , Ilkka Kylanpaa , Norm Tubman , Jaron Krogel , Sharon Hammes-Schiffer , David Ceperley

We discuss an alternative accurate Monte Carlo method to calculate the ground-state energy and related quantities for Laughlin states of the fractional quantum Hall effect in a disk geometry. This alternative approach allows us to obtain…

Mesoscale and Nanoscale Physics · Physics 2009-11-13 Orion Ciftja , Carlos Wexler

An inhomogeneous backflow transformation for many-particle wave functions is presented and applied to electrons in atoms, molecules, and solids. We report variational and diffusion quantum Monte Carlo VMC and DMC energies for various…

Computational Physics · Physics 2008-01-04 P. Lopez-Rios , A. Ma , N. D. Drummond , M. D. Towler , R. J. Needs

Describing correlated electron systems near phase transitions has been a major challenge in computational condensed-matter physics. In this paper, we apply highly accurate fixed node quantum Monte Carlo techniques, which directly work with…

Strongly Correlated Electrons · Physics 2018-01-10 Li Chen , Lucas K. Wagner

Atomic forces are calculated for first-row monohydrides and carbon monoxide within electronic quantum Monte Carlo (QMC). Accurate and efficient forces are achieved by using an improved method for moving variational parameters in variational…

Chemical Physics · Physics 2009-11-10 Myung Won Lee , Massimo Mella , Andrew M. Rappe

We develop a method for calculating the fundamental electronic gap of semiconductors and insulators using grand canonical Quantum Monte Carlo simulations. We discuss the origin of the bias introduced by supercell calculations of finite size…

Materials Science · Physics 2020-02-12 Yubo Yang , Vitaly Gorelov , Carlo Pierleoni , David M. Ceperley , Markus Holzmann

We use variational quantum Monte Carlo to calculate the density-functional exchange-correlation hole n_{xc}, the exchange-correlation energy density e_{xc}, and the total exchange-correlation energy E_{xc}, of several electron gas systems…

Materials Science · Physics 2009-10-31 Maziar Nekovee , W. M. C. Foulkes , R. J. Needs

Using Quantum Monte Carlo (QMC) calculations, we investigate the insulator-metal transition observed in liquid hydrogen at high pressure. Below the critical temperature of the transition from the molecular to the atomic liquid, the…

Materials Science · Physics 2020-11-25 Vitaly Gorelov , David M. Ceperley , Markus Holzmann , Carlo Pierleoni

In this paper we propose an ab initio method to solve quantum many-body problems of molecular dynamics where both the electronic and the nuclear degrees are represented by ensembles of trajectories and guiding waves in physical space. Both…

Atomic Physics · Physics 2025-01-28 Ivan P. Christov

Path integral Monte Carlo approach is used to study the coupled quantum dynamics of the electron and nuclei in hydrogen molecule ion. The coupling effects are demonstrated by comparing differences in adiabatic Born--Oppenheimer and…

Chemical Physics · Physics 2008-12-29 I. Kylänpää , M. Leino , T. T. Rantala
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