arXiv Machine Learning

Backward SDEs-based Diffusion for Physics-Constrained Generation

arXiv AI
Sep 4

A Posterior-Dynamics Framework for Imaging Inverse Problems with Pretrained Diffusion Priors

The paper introduces a Posterior‑Dynamics Framework that leverages pretrained diffusion models as multiscale priors for linear imaging inverse problems such as deblurring, super‑resolution, and inpainting. By constructing a surrogate likelihood centered on the clean image and incorporating diffusion uncertainty, the authors derive continuous posterior dynamics and a tunable Langevin component for adaptive exploration. They prove theoretical guarantees (endpoint consistency, finite‑horizon tracking, weak accuracy) and present the PD‑IMEX sampler, which achieves high‑quality reconstructions with only 100 score evaluations and controllable fidelity‑diversity trade‑offs.

By Zhaoqiang Liu, Tongyao Pang, Ruibing Wang, Yang Zheng
arXiv Machine Learning
Oct 12

SBNO : Schr\"odinger Bridge Neural Operator for the Forward and Inverse Problems under Missing Information

SBNO (Schr"odinger Bridge Neural Operator) is an equation‑free framework that learns conditional operators for both forward and inverse PDE problems using paired data and a diffusion Schr"odinger bridge matching approach. It preserves empirical input‑solution pairing through a mask‑aware endpoint coupling and supports both task directions within a single model. At inference, SBNO generates deterministic reconstructions via a probability‑flow ODE, achieving comparable or superior accuracy on five PDE benchmarks with only 5% observations, while being at least 9.7× faster and using 4.3× less GPU memory than guided‑diffusion baselines.

By Jaehyeon Park, Inhyeok Jeong, Noseong Park