Error Quantification and Mitigation for Numerical Compact Binary Waveforms

Citation

Habib, Sarah Mary (2025) Error Quantification and Mitigation for Numerical Compact Binary Waveforms. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/jbre-7e68. https://resolver.caltech.edu/CaltechTHESIS:06022025-193721130

Abstract

Gravitational wave analysis requires waveform models to compare with observed signals from compact binaries. These models are based on and validated by numerical relativity waveforms---waveforms output from codes developed to numerically evolve the Einstein field equations. The efficacy of numerical waveforms for analysis is limited by error from both numerical and astrophysical sources. This thesis makes two contributions to the quantification and mitigation of this error.

Chapter 2 describes a new algorithm for eccentricity reduction, the process of determining initial conditions for quasicircular binary orbits. This iterative procedure requires a measurement of eccentricity based on an early-inspiral trajectory. We find that the use of nonlinear fitting techniques such as variable projection leads to vastly improved consistency in eccentricity measurements.

Finally, Chapter 3 presents an in-depth quantification of error in numerical binary neutron star waveforms from three vastly different numerical relativity codes. We find that overall these codes produce consistent binary neutron star evolutions, but that further accuracy improvements will be required for analysis of next-generation gravitational wave detector signals.

Thesis Files