HYBRID MONTE-CARLO - AN EFFICIENT ALGORITHM FOR CONDENSED MATTER SIMULATION

A detailed comparison has been made of the performance of molecular dy namics and hybrid Monte Carlo simulation algorithms for calculating th ermodynamic properties of 2D Lennard-Jonesium. The hybrid Monte Carlo simulation required an order of magnitude fewer steps than the molecul ar dynamics simulation to calculate reproducible values of the specifi c heat. The ergodicity of the two algorithms was compared via the use of intermediate scattering functions. For classical systems the interm ediate scattering functions should be real; however, a simple analysis demonstrates that this function will have a significant imaginary com ponent when ergodicity breaks down. For q vectors near the zone bounda ry, the scattering functions are real for both algorithms. However, fo r q vectors near the zone center (i.e., harmonic, weakly coupled modes ), the scatttering function calculated via molecular dynamics had a si gnificantly larger imaginary component than that calculated using hybr id Monte Carlo. Therefore, the hybrid Monte Carlo algorithm is more er godic and samples phase space more efficiently than molecular dynamics for simulations of 2D Lennard-Jonesium. (C) 1994 by John Wiley and So ns, Inc.