A CONSTRAINED PATH MONTE CARLO METHOD FOR NUCLEON SYSTEMS

2001 ◽  
Vol 15 (10n11) ◽  
pp. 1510-1518 ◽  
Author(s):  
K. E. SCHMIDT ◽  
A. SARSA ◽  
S. FANTONI
Keyword(s):  
Monte Carlo ◽  
Monte Carlo Method ◽  
Ground State ◽  
Degrees Of Freedom ◽  
Diffusion Monte Carlo ◽  
Nucleon Potential ◽  
Sign Problem ◽  
Hypernetted Chain ◽  
Path Constraint ◽  
Spatial Degrees Of Freedom

By combining diffusion Monte Carlo for the spatial degrees of freedom and auxiliary field Monte Carlo to separate the spin-isospin operators, we can solve for the ground state of many-nucleon systems. We use a path constraint to control the fermion sign problem and apply the method to neutron systems interacting with the Argonne v′8 two nucleon potential and the Urbana IX three-nucleon potential. We compare our results with fermion hypernetted chain calculations.

Diffusion Monte Carlo study of excitons and biexcitons in a mass-asymmetric electron–hole bilayer

2017 ◽  
Vol 19 (31) ◽  
pp. 20778-20785 ◽  
Author(s):  
Rajesh O. Sharma ◽  
L. K. Saini ◽  
Bhagwati Prasad Bahuguna
Keyword(s):  
Monte Carlo ◽  
Monte Carlo Method ◽  
Ground State ◽  
Monte Carlo Study ◽  
Diffusion Monte Carlo ◽  
Electron Hole ◽  
Bilayer System ◽  
System P ◽  
Diffusion Monte Carlo Method ◽  
Fixed Node

We employed the diffusion Monte Carlo method, under fixed node approximation, to investigate the various ground state properties of a mass-asymmetric electron–hole bilayer system.

scholarly journals Comparison of Calculations for the Hubbard Model Obtained with Quantum-Monte-Carlo, Exact, and Stochastic Diagonalization

1997 ◽  
Vol 08 (02) ◽  
pp. 397-415 ◽  
Author(s):  
Thomas Husslein ◽  
Werner Fettes ◽  
Ingo Morgenstern
Keyword(s):  
Monte Carlo ◽  
Monte Carlo Method ◽  
Hubbard Model ◽  
Ground State ◽  
Quantum Monte Carlo ◽  
Minus Sign ◽  
Sign Problem ◽  
Quantum Monte Carlo Method ◽  
Convergence Problems ◽  
Superconducting Correlations

In this paper we compare numerical results for the ground state of the Hubbard model obtained by Quantum-Monte-Carlo simulations with results from exact and stochastic diagonalizations. We find good agreement for the ground state energy and superconducting correlations for both, the repulsive and attractive Hubbard model. Special emphasis lies on the superconducting correlations in the repulsive Hubbard model, where the small magnitude of the values obtained by Monte-Carlo simulations gives rise to the question, whether these results might be caused by fluctuations or systematic errors of the method. Although we notice that the Quantum-Monte-Carlo method has convergence problems for large interactions, coinciding with a minus sign problem, we confirm the results of the diagonalization techniques for small and moderate interaction strengths. Additionally we investigate the numerical stability and the convergence of the Quantum-Monte-Carlo method in the attractive case, to study the influence of the minus sign problem on convergence. Also here in the absence of a minus sign problem we encounter convergence problems for strong interactions.

Ab initio investigation on the low-lying states of LaX (X = Se, Sn, Sb)

2021 ◽  
pp. 1-6
Author(s):  
Nagat Elkahwagy ◽  
Mahmoud Abdelfatah ◽  
Atif Ismail
Keyword(s):  
Density Functional Theory ◽  
Monte Carlo ◽  
Monte Carlo Method ◽  
Ground State ◽  
Vibrational Frequency ◽  
Density Functional ◽  
Electronic States ◽  
Diffusion Monte Carlo ◽  
Functional Theory ◽  
Diffusion Monte Carlo Method

Potential energy curves for the low-lying electronic states of the title molecules in their neutral and anionic forms have been calculated by means of the diffusion Monte Carlo method. The effect of different trial functionals has been investigated using single determinants constructed from density functional theory (DFT) orbitals with B3LYP, B3PW91, and M06-2X functions. Bond length, vibrational frequency, and electron affinity have also been numerically derived for the selected species and the ground state has been assigned. Spectroscopic parameters obtained are interpreted and compared to their isovalents, shedding some light on further investigations on the selected dimers.

Sign in / Sign up

Export Citation Format

Share Document