Change search
Link to record
Permanent link

Direct link
Doeser, Ludvig
Publications (1 of 1) Show all publications
Doeser, L., Ata, M. & Jasche, J. (2025). Learning the Universe: Learning to optimize cosmic initial conditions with non-differentiable structure formation models. Monthly notices of the Royal Astronomical Society, 542(2), 1403-1422
Open this publication in new window or tab >>Learning the Universe: Learning to optimize cosmic initial conditions with non-differentiable structure formation models
2025 (English)In: Monthly notices of the Royal Astronomical Society, ISSN 0035-8711, E-ISSN 1365-2966, Vol. 542, no 2, p. 1403-1422Article in journal (Refereed) Published
Abstract [en]

Making the most of next-generation galaxy clustering surveys requires overcoming challenges in complex, non-linear modelling to access the significant amount of information at smaller cosmological scales. Field-level inference has provided a unique opportunity beyond summary statistics to use all of the information of the galaxy distribution. However, addressing current challenges often necessitates numerical modelling that incorporates non-differentiable components, hindering the use of efficient gradient-based inference methods. In this paper, we introduce Learning the Universe by Learning to Optimize (LULO), a gradient-free framework for reconstructing the 3D cosmic initial conditions. Our approach advances deep learning to train an optimization algorithm capable of fitting state-of-the-art non-differentiable simulators to data at the field level. Importantly, the neural optimizer solely acts as a search engine in an iterative scheme, always maintaining full physics simulations in the loop, ensuring scalability and reliability. We demonstrate the method by accurately reconstructing initial conditions from halos identified in a dark matter-only N-body simulation with a spherical overdensity algorithm. The derived dark matter and halo overdensity fields exhibit cross-correlation with the ground truth into the non-linear regime Mpc. Additional cosmological tests reveal accurate recovery of the power spectra, bispectra, halo mass function, and velocities. With this work, we demonstrate a promising path forward to non-linear field-level inference surpassing the requirement of a differentiable physics model.

Keywords
software: machine learning, early Universe, large-scale structure of Universe
National Category
Astronomy, Astrophysics and Cosmology
Identifiers
urn:nbn:se:su:diva-246672 (URN)10.1093/mnras/staf1289 (DOI)001559618700001 ()2-s2.0-105014738017 (Scopus ID)
Available from: 2025-09-09 Created: 2025-09-09 Last updated: 2025-09-09Bibliographically approved
Organisations

Search in DiVA

Show all publications