Practical multiple-copy methods for sampling classical statistical mechanical ensembles

We present a multiple-copy molecular dynamics (MD) simulation method based on our rigorously-derived mean field algorithm [Phys. Rev. E 64 (2001) 026701]. The algorithm is extended to constant temperature ensembles and then tested for equilibrium properties including temperature equilibration times and pair radial distribution functions. The method improves on conventional multiple-copy methods because it incorporates minor pseudoparticles they ignore, yet it retains their sampling advantage over conventional MD. The current method also incorporates a parameter that allows continuous scaling between conventional multiple-copy dynamics and conventional MD for an ensemble of systems. The parameter may be chosen to strike a compromise between accuracy and computer time requirements.