Consistent Sampling and Simulation: Molecular Dynamics with Energy-Based Diffusion Models

Understand

In recent years, diffusion models trained on equilibrium molecular distributions have proven effective for sampling biomolecules.

• Beyond direct sampling, the score of such a model can also be used to derive the forces that act on molecular systems.
• However, while classical diffusion sampling usually recovers the training distribution, the corresponding energy-based interpretation of the learned score is often inconsistent with this distribution, even for low-dimensional toy systems.
• We trace this inconsistency to inaccuracies of the learned score at very small diffusion timesteps, where the model must capture the correct evolution of the data distribution.