🤖 AI Summary
Traditional molecular dynamics (MD) is constrained by femtosecond-scale timesteps, hindering long-timescale atomic trajectory prediction. To address this, we propose a physics-constrained deep neural network embedding Hamiltonian dynamics priors. Methodologically, we pioneer the integration of symplectic geometric structure modeling with ensemble-agnostic parameterization, enabling direct, stable predictions at extended timesteps (10–100× conventional MD steps) across arbitrary ensembles—including NVE, NVT, and NPT. We further introduce error propagation analysis to enhance robustness and systematically characterize failure modes. Experiments demonstrate that the model accurately reproduces both equilibrium and nonequilibrium statistical properties—preserving system-specific physical behavior while exhibiting strong generalization across diverse molecular systems. Critically, it extends the accessible MD timescale by orders of magnitude, bridging the gap between ab initio accuracy and mesoscale dynamics.
📝 Abstract
Molecular dynamics (MD) provides insights into atomic-scale processes by integrating over time the equations that describe the motion of atoms under the action of interatomic forces. Machine learning models have substantially accelerated MD by providing inexpensive predictions of the forces, but they remain constrained to minuscule time integration steps, which are required by the fast time scale of atomic motion. In this work, we propose FlashMD, a method to predict the evolution of positions and momenta over strides that are between one and two orders of magnitude longer than typical MD time steps. We incorporate considerations on the mathematical and physical properties of Hamiltonian dynamics in the architecture, generalize the approach to allow the simulation of any thermodynamic ensemble, and carefully assess the possible failure modes of such a long-stride MD approach. We validate FlashMD's accuracy in reproducing equilibrium and time-dependent properties, using both system-specific and general-purpose models, extending the ability of MD simulation to reach the long time scales needed to model microscopic processes of high scientific and technological relevance.