arXiv:2502.14025v1 Announce Type: new
Abstract: The Simulating eXtreme Spacetimes Collaboration’s code SpEC can now routinely simulate binary black hole mergers undergoing $sim25$ orbits, with the longest simulations undergoing nearly $sim180$ orbits. While this sounds impressive, the mismatch between the highest resolutions for this long simulation is $mathcal{O}(10^{-1})$. Meanwhile, the mismatch between resolutions for the more typical simulations tends to be $mathcal{O}(10^{-4})$, despite the resolutions being similar to the long simulations’. In this note, we explain why mismatch alone gives an incomplete picture of code — and waveform — quality, especially in the context of providing waveform templates for LISA and 3G detectors, which require templates with $mathcal{O}(10^{3}) – mathcal{O}(10^{5})$ orbits. We argue that to ready the GW community for the sensitivity of future detectors, numerical relativity groups must be aware of this caveat, and also run future simulations with at least three resolutions to properly assess waveform accuracy.
Future Roadmap for Readers: Challenges and Opportunities
Introduction
This article discusses the limitations of current simulations in accurately predicting gravitational wave (GW) waveforms, specifically in the context of providing waveform templates for future GW detectors like LISA and 3G detectors. It explains the importance of running simulations with higher resolutions and proposes a future roadmap for numerical relativity groups to enhance waveform accuracy.
Limitations of Current Simulations
The article highlights that while the current simulations using the code SpEC can simulate binary black hole mergers for a significant number of orbits (up to nearly 180 orbits), the resolution used in these simulations results in a significant mismatch compared to higher resolution simulations. The mismatch is on the order of $mathcal{O}(10^{-4})$ for typical simulations and $mathcal{O}(10^{-1})$ for longer simulations. This indicates that the quality of the code and waveform is not accurately represented by mismatch alone.
Importance of High-Resolution Simulations
The article emphasizes the need for waveform templates that accurately represent the behavior of GW signals for future detectors, which require templates with $mathcal{O}(10^{3}) – mathcal{O}(10^{5})$ orbits. To achieve this, numerical relativity groups must be aware of the limitations caused by mismatch and run simulations with at least three resolutions to properly assess waveform accuracy.
Roadmap for Enhancing Waveform Accuracy
- Awareness: Numerical relativity groups must be aware of the limitations of mismatch in assessing waveform accuracy. This requires understanding the incomplete picture provided by mismatch alone.
- Higher Resolutions: To improve waveform accuracy, future simulations should be conducted with higher resolutions. This will help reduce the mismatch between simulations and provide more reliable waveform templates for future detectors.
- Multi-Resolution Simulations: Simulations should be run with at least three resolutions to properly assess waveform accuracy. This will allow for a more comprehensive understanding of the code quality and waveform behavior.
Conclusion
The challenges and opportunities on the horizon involve improving the accuracy of GW waveform templates for future detectors. By addressing the limitations of mismatch and conducting simulations with higher resolutions, numerical relativity groups can provide more reliable waveform predictions. This roadmap will help prepare the GW community for the sensitivity of future detectors and enhance our understanding of extreme spacetimes.