Researchers have developed an artificial intelligence (AI) model to accelerate the generation of gravitational waveforms, a crucial step for parameter estimation in binary coalescence events. This advancement is significant given that the global network of gravitational-wave detectors has recorded over 350 events, and third-generation detectors, such as the Einstein Telescope, are expected to detect many more with more complex characteristics, including eccentric orbits and high-mass ratio binaries. Parameter estimation for these signals is computationally very expensive, and AI offers a way to reduce this cost.
The proposed model is a two-stage deterministic conditional autoencoder, designed to generate four-parameter SEOBNRv4 waveforms. The first stage of the model generates the amplitude and phase series of the waveform, while the second stage calibrates the residual error in the predictions. This approach achieved a median mismatch of approximately 10<sup>-2</sup> with the target polarization waveforms, and the calibrated amplitude/phase series reached a 10<sup>-6</sup> level cosine distance error. Subsequently, a waveform conditioning step is proposed to enable the use of these surrogate waveforms in downstream parameter estimation tasks.
Although initial parameter estimation tests with AI-generated and EOB (Effective One Body) waveform injections showed a systematic bias in the inferred posteriors, researchers have demonstrated that this inherent bias can be estimated and corrected. By importance reweighting of posterior samples, it is possible to use lower-accuracy surrogate waveforms at low signal-to-noise ratios (SNRs). This method promises to drastically reduce computation time, making the analysis of the vast amount of data expected from future detectors feasible.