Hybrid Physical-Neural Simulator for Fast Cosmological Hydrodynamics

Fuente: arXiv
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Hauptverfasser: Thomsen, Arne, Tröster, Tilman, Lanusse, François
Format: Preprint
Veröffentlicht: 2025
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author Thomsen, Arne
Tröster, Tilman
Lanusse, François
author_facet Thomsen, Arne
Tröster, Tilman
Lanusse, François
contents Cosmological field-level inference requires differentiable forward models that solve the challenging dynamics of gas and dark matter under hydrodynamics and gravity. We propose a hybrid approach where gravitational forces are computed using a differentiable particle-mesh solver, while the hydrodynamics are parametrized by a neural network that maps local quantities to an effective pressure field. We demonstrate that our method improves upon alternative approaches, such as an Enthalpy Gradient Descent baseline, both at the field and summary-statistic level. The approach is furthermore highly data efficient, with a single reference simulation of cosmological structure formation being sufficient to constrain the neural pressure model. This opens the door for future applications where the model is fit directly to observational data, rather than a training set of simulations.
format Preprint
id arxiv_https___arxiv_org_abs_2510_26593
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Hybrid Physical-Neural Simulator for Fast Cosmological Hydrodynamics
Thomsen, Arne
Tröster, Tilman
Lanusse, François
Cosmology and Nongalactic Astrophysics
Machine Learning
Cosmological field-level inference requires differentiable forward models that solve the challenging dynamics of gas and dark matter under hydrodynamics and gravity. We propose a hybrid approach where gravitational forces are computed using a differentiable particle-mesh solver, while the hydrodynamics are parametrized by a neural network that maps local quantities to an effective pressure field. We demonstrate that our method improves upon alternative approaches, such as an Enthalpy Gradient Descent baseline, both at the field and summary-statistic level. The approach is furthermore highly data efficient, with a single reference simulation of cosmological structure formation being sufficient to constrain the neural pressure model. This opens the door for future applications where the model is fit directly to observational data, rather than a training set of simulations.
title Hybrid Physical-Neural Simulator for Fast Cosmological Hydrodynamics
topic Cosmology and Nongalactic Astrophysics
Machine Learning
url https://arxiv.org/abs/2510.26593