Light-Weight Diffusion Multiplier and Uncertainty Quantification for Fourier Neural Operators
Fourier Neural Operators (FNOs) suffer from poor scalability due to over-parameterization and lack intrinsic uncertainty quantification (UQ), while existing posterior UQ methods compromise their geometric inductive bias. To address these issues, we propose DINOZAUR: the first FNO variant that embeds a heat-kernel diffusion process into the spectral multiplier design, replacing high-dimensional tensor parameters with a single time-varying scalar—enabling lightweight modeling. Concurrently, we introduce a Bayesian prior directly in the frequency domain, enabling geometrically consistent, calibration-aware UQ. DINOZAUR thus achieves both efficiency and reliability: it attains state-of-the-art or competitive accuracy across multiple PDE benchmarks, with significantly reduced parameter count and memory footprint, while producing spatially correlated, statistically calibrated uncertainty estimates.