arXiv Machine Learning

TNFlow: Amortized Posterior Inference for Trans-Neptunian Object Surface Composition

TNFlow is a transformer‑based normalizing flow model designed to infer the surface composition of Trans‑Neptunian Objects (TNOs) from their reflectance spectra. It is trained on synthetic spectra generated by the Shkuratov radiative transfer model and can invert a spectrum in about 0.7 s on a single CPU core, producing a multimodal posterior over simplex‑valid compositions and grain sizes. On synthetic data, the model’s highest‑weight mode achieves a mean total‑variation distance of 0.149 from ground truth, and it generalizes well to unseen component combinations, though qualitative tests on real JWST spectra reveal potential biases linked to simulator fidelity or training data.

arXiv Statistics ML
Aug 27

Posterior Inference of Hamiltonian Parameters from RIXS Spectroscopy

The paper reports the first use of simulation‑based inference for resonant inelastic X‑ray scattering (RIXS) spectroscopy, applying truncated marginal neural ratio estimation and conditional flow matching to infer full posterior distributions of Hamiltonian parameters for two Ni$^{2+}$ compounds. A vision‑transformer encoder tailored to the RIXS map’s physical layout produces sharper, better‑covered posteriors than generic image encoders. The validated method, applied to experimental data, uncovers parameter correlations invisible to point estimators and yields posterior predictive distributions that closely match observed spectra, enabling new analyses such as nuisance‑marginalized uncertainty quantification, multi‑measurement posterior fusion, and active experimental design.

By Samuel Klein, Thomas M. Linker, Louis Conreux, Daniel Ratner, Apurva Mehta, Makoto Tachibana, Jiemin Li, Jonathan Pelliciari, Valentina Bisogni, Wei He, Xiangpeng Luo, Mark P. M. Dean, Marton K. Lajer, Michael Kagan, Joshua J. Turner, Yongqiang Cheng, Sean Gasiorowski
arXiv Machine Learning
Aug 28

Cross-simulator transfer with foundation model summaries: Towards robust SKA-era reionization inference

The paper demonstrates that a self‑supervised Vision Transformer (ViT) pretrained on a fast, low‑cost semi‑numerical simulator can produce data summaries that transfer across different simulators without retraining. In 21cm cosmology, the ViT—named SKATR—pretrained on 67,000 21cmFAST lightcones is applied unchanged to hydrodynamical Loreli II lightcones, enabling accurate inference of five astrophysical parameters with fewer radiative‑transfer simulations than a fully‑supervised baseline. SKATR remains accurate, informative, and calibrated even under realistic SKA antenna array noise, outperforming supervised models retrained on noisy data.

By Yannic Pietschke, Caroline Heneka, Ayodele Ore, Romain Meriot
arXiv Computer Vision
1d ago

VolS-GS: Relightable Gaussian Splatting with Volumetric Subsurface Scattering

VolS-GS is a relightable Gaussian splatting framework that reconstructs objects from one-light-at-a-time captures and renders them under novel lighting and viewpoints. It addresses the difficulty of modeling non‑local effects such as subsurface scattering by using the spatial support of the Gaussian scene as the domain of a differentiable finite‑volume transport solver, allowing light to propagate through the object's interior. A small network predicts scattering and absorption coefficients for each Gaussian, and the solver redistributes incident light, while a shadow term and regularizer prevent learned shadow and specular terms from dominating the appearance. "whyItMatters":"The approach improves relighting quality on held‑out lights and views across three OLAT benchmarks, demonstrating its effectiveness for realistic rendering of subsurface scattering effects."

By Junyeong Ahn, Jaegul Choo
arXiv Machine Learning
Sep 4

Hadronic Mono-Z Dark Matter Sensitivity with Flow Matching on CMS Open Data

The paper projects the sensitivity of a hadronic mono‑Z dark‑matter search using CMS Run 2015D HTMHT open data (2.256 fb⁻¹). A conditional flow‑matching normalizing flow models backgrounds, with careful handling of missing features and a sentinel imputation strategy. The baseline analysis yields expected significances of 2.89σ, 7.62σ, and 7.41σ for three benchmark models, and an ablation study shows that extra‑jet kinematics contribute 53–71% of the discriminating power.

By Hitesh Rasineni (VIT-AP University, Amaravati, India), Bhavishya Chebrolu (Mohan Babu University, Tirupati, India)
arXiv Computer Vision
Sep 17

STRADAViT: Self-Supervised Domain Adaptation of Vision Transformer Backbones for Radio Astronomy

STRADAViT is a self‑supervised continued‑pretraining framework that adapts Vision Transformer (ViT) backbones for radio‑astronomy image analysis. It curates mixed‑survey data, generates radio‑astronomy‑aware training views, and initializes encoders with ViT‑MAE, optionally adding register tokens. Evaluations on three morphology benchmarks (MiraBest, LoTSS DR2, and Radio Galaxy Zoo) show that a register‑based two‑stage checkpoint improves linear‑probe Macro‑F1 scores over the ViT‑MAE baseline and enhances fine‑tuning on MiraBest and RGZ DR1, though performance on LoTSS DR2 fine‑tuning declines; these differences are statistically significant.

By Andrea DeMarco, Ian Fenech Conti, Hayley Camilleri, Ardiana Bushi, Simone Riggi
arXiv AI
Jun 3

Ref-DGS: Reflective Dual Gaussian Splatting

arXiv:2603. 07664v3 Announce Type: replace-cross Abstract: The reflective appearance, especially strong and typically near-field specular reflections, poses a fundamental challenge for accurate surface reconstruction and novel view synthesis.

By Ningjing Fan, Yiqun Wang, Dongming Yan, Peter Wonka