Stable schemes for dissipative particle dynamics with conserved energy
This work addresses the stability bottleneck in energy-conserving dissipative particle dynamics simulations, enabling longer timesteps for systems with small heat capacities.
The authors propose a new numerical scheme for dissipative particle dynamics with conserved energy that uses Metropolis-Hastings steps to enforce non-negative internal energies, enabling larger timesteps and improved stability. The method allows timesteps limited only by the Hamiltonian dynamics, with potential for multiple timestep strategies.
This article presents a new numerical scheme for the discretization of dissipative particle dynamics with conserved energy. The key idea is to reduce elementary pairwise stochastic dynamics (either fluctuation/dissipation or thermal conduction) to effective single-variable dynamics, and to approximate the solution of these dynamics with one step of a Metropolis-Hastings algorithm. This ensures by construction that no negative internal energies are encountered during the simulation, and hence allows to increase the admissible timesteps to integrate the dynamics, even for systems with small heat capacities. Stability is only limited by the Hamiltonian part of the dynamics, which suggests resorting to multiple timestep strategies where the stochastic part is integrated less frequently than the Hamiltonian one.