Ground State Properties of Three-Dimensional Acoustic Polarons

1998 ◽  
Vol 12 (19) ◽  
pp. 775-783 ◽  
Author(s):  
Xiaoqun Wang
Keyword(s):  
Monte Carlo ◽  
Strong Coupling ◽  
Path Integral ◽  
Ground State ◽  
Three Dimensional ◽  
Strong Coupling Regime ◽  
Phonon Interaction ◽  
Path Integral Monte Carlo ◽  
Electron Phonon Interaction ◽  
Ground State Properties

The ground state properties of a three-dimensional acoustic polaron are studied using the path integral Monte Carlo technique. In the strong coupling regime, there exists a self-trapped state, which originates from a short ranged electron–phonon interaction, and is of delocalized nature.

scholarly journals EXCHANGE FREQUENCIES IN THE 2D WIGNER CRYSTAL

2003 ◽  
Vol 17 (28) ◽  
pp. 4965-4974 ◽  
Author(s):  
B. BERNU ◽  
P. GIANINETTI ◽  
LADIR CÂNDIDO ◽  
D. M. CEPERLEY
Keyword(s):  
Magnetic Field ◽  
Monte Carlo ◽  
Path Integral ◽  
Ground State ◽  
Spin Exchange ◽  
Wigner Crystal ◽  
Spin Liquid ◽  
Low Density ◽  
Spin Hamiltonian ◽  
Path Integral Monte Carlo

Path Integral Monte Carlo is used to calculate exchange frequencies as electrons undergo ring exchanges in a "clean" 2d Wigner crystal as a function of density. Agreement with WKB calculations is found at very low density, but the results show an enhanced increase with density near melting. Remarkably, the exchange Hamiltonian closely resembles the measured exchanges in 2d3 He . Using the resulting multi-spin exchange model we find the spin Hamiltonian for rs ≥ 175 ± 10 is a frustrated antiferromagnetic, with a spin liquid ground state. For lower density the ground state will be ferromagnetic. Some effects of a magnetic field are presented.

USING DISCRETE VARIABLE REPRESENTATION PATH INTEGRAL MONTE CARLO WITH METROPOLIS SAMPLING TO COMPUTE GROUND STATE WAVEFUNCTIONS

2007 ◽  
Vol 06 (02) ◽  
pp. 309-321 ◽  
Author(s):  
YINGSHENG XIAO ◽  
BILL POIRIER
Keyword(s):  
Monte Carlo ◽  
Path Integral ◽  
Ground State ◽  
Performance Enhancement ◽  
Discrete Variable ◽  
Discrete Variable Representation ◽  
Time Step ◽  
Path Integral Monte Carlo ◽  
Ground State Wavefunction ◽  
Variable Representation

The discrete variable representation (DVR) matrix dynamics formulation of the path integral Monte Carlo (PIMC) method, implemented numerically in a way that enables Metropolis sampling to be employed, is proposed as a means of computing ground state quantum wavefunctions. A key advantage of the DVR-PIMC approach is that customized marginal potentials may be employed, leading to significantly larger PIMC time step sizes, and substantial reductions in computational (CPU) effort. An additional key advantage of the present implementation is that the DVR provides a natural set of interpolant functions that can be used for accurate interpolation and extrapolation of function and tensor quantities away from predefined grid points. The new method is applied here to compute the ground state wavefunction of a model one degree-of-freedom (1 DOF) Morse oscillator system. A one-to-two order-of-magnitude reduction in CPU effort is observed, in comparison with a conventional PIMC simulation. The generalization for many DOFs is straightforward, and expected to result in even greater performance enhancement.

Constructing accurate interaction potentials to describe the microsolvation of protonated methane by helium atoms

2017 ◽  
Vol 19 (12) ◽  
pp. 8307-8321 ◽  
Author(s):  
Dennis Kuchenbecker ◽  
Felix Uhl ◽  
Harald Forbert ◽  
Georg Jansen ◽  
Dominik Marx
Keyword(s):  
Monte Carlo ◽  
Monte Carlo Simulations ◽  
Ab Initio ◽  
Path Integral ◽  
Interaction Potential ◽  
Stationary Point ◽  
Path Integral Monte Carlo ◽  
Interaction Potentials ◽  
Helium Atoms

An ab initio-derived interaction potential is derived and used in path integral Monte Carlo simulations to investigate stationary-point structures of CH5+ microsolvated by up to four helium atoms.

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