arXiv Statistics ML

Nested Sampling: A Critical and Comprehensive Theoretical Guide

The paper "Nested Sampling: A Critical and Comprehensive Theoretical Guide" offers an in‑depth derivation of the nested sampling (NS) technique, clarifying its theoretical foundations and practical challenges. It explains how NS efficiently explores high‑likelihood regions, discusses its connections to importance sampling and vertical Monte Carlo, and highlights both strengths and limitations. The work serves as both a tutorial for newcomers and a critical review for experienced practitioners, aiming to inspire future enhancements and more efficient implementations across scientific fields.

arXiv Machine Learning
Jun 26

Estimating Orbital Parameters of Direct Imaging Exoplanet Using Neural Network

arXiv:2510. 17459v3 Announce Type: replace-cross Abstract: In this work, we propose a flow-matching Markov chain Monte Carlo (FM-MCMC) algorithm for estimating the orbital parameters of exoplanetary systems, especially for those only one exoplanet is involved.

By Bo Liang, Hanlin Song, Chang Liu, Tianyu Zhao, Yuxiang Xu, Zihao Xiao, Manjia Liang, Minghui Du, Wei-Liang Qian, Li-e Qiang, Peng Xu, Ziren Luo
arXiv AI
Oct 28

ASTROLABE: A 3D Particle-Level Surrogate for Cosmology Simulation with Physical Flow Matching

ASTROLABE is a flow‑matching generative emulator that operates directly on the 6N phase‑space coordinates of individual particles, avoiding voxel grids and allowing any observable to be measured from inference. It uses a field‑particle hybrid transformer so that compute and memory scale linearly with the number of particles, and incorporates physical flow matching by basing the prior on COLA‑derived coordinates with momentum and mass conservation enforced throughout the flow. In Lambda‑CDM tests, ASTROLABE reproduces realistic fields, accurate power spectra, halo mass functions, velocity profiles, and halo density profiles, and it generalizes to out‑of‑distribution dark‑acoustic oscillation initial conditions while also being fine‑tuned to emulate large‑scale simulations such as TNG50‑3‑dark at a fraction of the cost.

By Ibrahim Elsharkawy, David Curtin, Yonatan Kahn, Neal Weiner
arXiv Computer Vision
Sep 7

Mapping Dark-Matter Clusters via Physics-Guided Diffusion Models

The paper presents a fully automated method for reconstructing the surface mass density of galaxy clusters using photometry and gravitational lensing data. It introduces DarkClusters-15k, a benchmark dataset of 15,000 simulated clusters with paired mass and photometry maps across multiple redshifts and simulation frameworks. By training a diffusion prior on this dataset, the authors generate posterior samples constrained by weak- and strong-lensing observables, achieving accurate, physics‑guided reconstructions with well‑calibrated uncertainties in minutes.

By Diego Royo, Brandon Zhao, Adolfo Mu\~noz, Diego Gutierrez, Katherine L. Bouman
arXiv Machine Learning
Jun 11

Interpretable Neural Marked Statistics for Cosmological Inference

arXiv:2606. 11295v1 Announce Type: cross Abstract: Recovering cosmological information beyond the power spectrum is a central goal for upcoming cosmological surveys, since late-time non-Gaussian signal in the matter density cannot be accessed through two-point statistics alone.

By Federico Semenzato, Benjamin D. Wandelt, Michele Liguori, Alvise Raccanelli