arXiv Statistics ML

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.

arXiv Machine Learning
Jul 30

Data Fusion and Contrastive Alignment for Unconstrained IR Molecular Structure Elucidation

arXiv:2607. 26164v1 Announce Type: new Abstract: Automated molecular structure elucidation from infrared (IR) spectroscopy data has seen significant advancements in recent years, but its broad applicability is limited by a reliance on pre-determined chemical formulas provided as auxiliary model inputs.

By Ethan J. Mick, Campbell A. Sweet, Matthias J. Young, Derek T. Anderson
arXiv Machine Learning
Sep 7

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.

By Agastya Gaur (University of Illinois Urbana-Champaign, SETI Institute), Cristina M. Dalle Ore (Carl Sagan Center, SETI Institute), Alessandra Ricca (NASA Ames Research Center, NASA Ames Research Center)
arXiv Computer Vision
Sep 7

BEAM3R: Beam's-eye-view architecture with Mamba-3 for implicit dose reconstruction

BEAM3R is a dose estimation framework that operates in beam’s-eye-view (BEV) for both photon and proton beamlet calculations. It uses a Mamba‑3 state‑space depth‑sequence core combined with physics‑based transport conditioning, sharing a 2D CNN encoder‑decoder architecture to process per‑plane BEV slices. The system achieves high accuracy on the DoseRAD2026 challenge, with local gamma pass rates above 96% for CT‑based models and runtimes under 25 s for photon and 18 s for proton predictions.

By Chen Cheng, Michael Ferraro, James Grover, David E J Waddington, Emily Hewson
arXiv Machine Learning
Jun 10

Unsupervised Deep Learning for Limited-Angle STEM-EDX Tomography -- Application to 3D Chemical Analysis of Phase-Change Memory Devices

arXiv:2606. 10547v1 Announce Type: cross Abstract: Energy Dispersive X-ray (EDX) tomography in Scanning Transmission Electron Microscopy (STEM) enables 3D compositional and elemental mapping at the nanoscale, but its use is limited by restricted tilt ranges and low-dose conditions required to avoid beam damage.

By Daniel del Pozo Bueno, Serge Brosset, Theo Monniez, Gabriele Navarro, Philippe Ciuciu, Zineb Saghi
arXiv Machine Learning
Jul 8

Multimodal Molecular Representation Learning with Graph Neural Networks, Deep & Cross Networks, and SMILES Embeddings

arXiv:2607. 05736v1 Announce Type: new Abstract: Molecular property prediction often relies on isolated data modalities, where continuous 3D graph neural networks (GNNs) struggle to efficiently capture long-range topological dependencies and exact macroscopic heuristics.

By Qiwei Han, Chi Zhou, Ruobing Wang, Zheng Ma
arXiv Machine Learning
Aug 13

NAE: Normalizing AutoEncoder

arXiv:2608. 12084v1 Announce Type: new Abstract: We consider the setting of Normalizing flows with approximate inverses, an established paradigm spanning both full-dimensional ($d=D$) and bottleneck ($d<D$) settings, and group these models under the term flow autoencoders.

By Muhammad Abdur Rafae, Niels Landwehr