Gravitational-wave approximants are essential for gravitational-wave astronomy, allowing the coverage binary black hole parameter space for inference or match filtering without costly numerical relativity (NR) simulations, but generally trading some accuracy for computational efficiency. To reduce this trade-off, NR surrogate models can be constructed using interpolation within NR waveform space. We present a 2-stage training approach for neural network-based NR surrogate models. Initially trained on approximant-generated waveforms and then fine-tuned with NR data, these dual-stage artificial neural surrogate (\texttt{DANSur}) models offer rapid and competitively accurate waveform generation, generating millions in under 20ms on a GPU while keeping mean mismatches with NR around 10−4. Implemented in the \textsc{bilby} framework, we show they can be used for parameter estimation tasks.
@article{arxiv.2412.06946,
title = {A Deep Learning Powered Numerical Relativity Surrogate for Binary Black Hole Waveforms},
author = {Osvaldo Gramaxo Freitas and Anastasios Theodoropoulos and Nino Villanueva and Tiago Fernandes and Solange Nunes and José A. Font and Antonio Onofre and Alejandro Torres-Forné and José D. Martin-Guerrero},
journal= {arXiv preprint arXiv:2412.06946},
year = {2025}
}