arXiv Machine Learning

Flexible Spectral-Normalized Neural Gaussian Process for Dynamic Aperture Prediction

arXiv Machine Learning
Aug 21

Heteroscedastic Neural Surrogate Modeling for Robust and Rapid Bayesian Inference in Fusion Plasma Diagnostics

arXiv:2608. 19377v1 Announce Type: cross Abstract: Bayesian inference via Markov Chain Monte Carlo (MCMC) provides effective parameter estimation, but its real-time application in complex physical systems is hindered by heavy computational bottlenecks and extreme sensitivity to statistical noise.

By Liyun Zhang, Naoya Mamada, Kentaro Sakai, Takeo Hoshi, Toru Aonishi
arXiv Machine Learning
Sep 10

Mind the Gap: Navigating Inference with Optimal Transport Maps

The paper introduces a model calibration method using optimal transport to address discrepancies between simulation and experimental data in high-dimensional machine learning applications. Applied to jet tagging in particle physics, the technique calibrates a 128‑dimensional latent representation from a general‑purpose classifier, ensuring downstream derived quantities are properly calibrated. This enables more reliable use of foundation models for jet flavor analysis in LHC experiments and offers a general framework for correcting high‑dimensional simulations across scientific fields.

By Malte Algren, Tobias Golling, Francesco Armando Di Bello, Christopher Pollard
arXiv Machine Learning
Oct 16

Learn Only Where You Can't Compute: Structured Corrections to Gaussian Process Posteriors

The paper introduces a structured posterior‑correction framework that blends a tractable Gaussian reference with data‑driven corrections learned via diffusion models. After applying mean correction and covariance calibration, the diffusion model focuses on a low‑dimensional subspace that captures discrepancies from the Gaussian reference, while the remaining space stays Gaussian. Experiments on three scientific inference tasks show that these corrections recover hidden modes, improve sample structure, and reduce prediction error compared to the Gaussian reference, with trade‑offs between accuracy and computational cost relative to full‑field generative models.

By Tobias Weber, Carla Sagebiel, Philipp Hennig
arXiv AI
Oct 9

Uncovering and Fixing Collider Bias in Bayesian PINNs

The paper investigates a systematic bias in Bayesian physics-informed neural networks (B-PINNs) caused by their typical collider structure, where independent physical and trajectory parameters become coupled through likelihoods on differential-equation residuals. The authors demonstrate that this modeling choice can drive the posterior away from true parameter values, even with a well-centered prior. They propose a hierarchical chain model that avoids this bias, though it introduces a doubly intractable inference problem, which they solve by discretizing the dynamics and applying particle MCMC. Analytical approximations and diagnostic criteria are derived to predict when standard B-PINNs remain reliable, and experiments confirm both the bias and the effectiveness of the chain formulation.

By Michael Obermayr, Robert Peharz
arXiv AI
Oct 9

Scalable AI Uncertainty Quantification via Generalized Laplace Active Subspaces

The paper introduces a scalable method for uncertainty quantification in neural networks by applying a low‑rank generalized Laplace approximation within a data‑informed active subspace. It constructs a local Gaussian posterior around pretrained weights, calibrates the prior variance via empirical Bayes, and compares two posterior scalings: standard Bayesian and mean‑loss scaling. The study finds that mean‑loss scaling yields a more stable, lower‑dimensional subspace and produces calibrated, coherent predictive confidence intervals, whereas standard scaling can cause posterior variance contraction and degrade predictive coherence.

By Wouter N. Edeling, Peter V. Coveney
arXiv Machine Learning
4d ago

Towards Out-of-Distribution Uncertainty Quantification for Machine-Learned Interatomic Potentials via Pre-Training

The paper proposes pre-training uncertainty estimators on large, diverse materials science datasets to improve uncertainty quantification (UQ) for machine‑learned interatomic potentials (MLIPs). By evaluating these pre‑trained models on both in‑distribution and out‑of‑domain adsorption‑energy predictions, the authors demonstrate that zero‑shot UQ is viable and that fine‑tuning yields strong correlations between predicted uncertainty and actual prediction error, even on challenging datasets. This approach aims to provide foundational UQ models that enable broader, more reliable deployment of MLIPs across chemical space.

By Stefan P. Schmid, Tobias Setzer, Maximilian Scheurer