N-convergence in one–component plasma: Comparison of Coulomb, Ewald, and angular–averaged Ewald potentials

In this study, we investigate the dependence of potential energy of the one–component plasma on the number of particles with pure Coulomb, Ewald, and angular–averaged Ewald potentials. We show that in the weakly–coupled regime, the Coulomb potential provides a faster convergence of the energy to the thermodynamic limit. However, in the medium- and, especially, strong-coupling regime, the Ewald potential shows significantly better convergence. Thus, the criticism of the Ewald potential in [Fraser et al. Phys. Rev. B 53, 1814 (1996)] within classical simulations turns out to be unjustified in this case: the accounting for long-range interaction effects greatly improves the $N$-convergence of one–component plasma thermodynamic functions.