Postdoctoral Fellowship: MPS-Ascend: The Polarization of Gravitational Waves as a Fundamental Probe of Gravity

The direct detection of gravitational waves (GWs) has led to an explosion of new tests of general relativity (GR). This project supports Dr. Kristen Aloh in a postdoctoral Fellowship to leverage the polarization of GWs as a highly effective tool to test GR. The project will investigate whether the existence of additional polarizations is consistent with current data and examine the effectiveness of current search techniques for these additional polarizations. New models and data analysis software will be developed and implemented into open-source code to search for additional polarizations using future detector networks. Furthermore, novel visualization tools will inform the placement of new detectors in future networks to optimize these studies. This research is integrated with broader impact activities utilizing the same novel visualization tools. The first research focus of the project is to explore what information can be extracted about the polarization content of GWs using current GW detector networks. The energy contained in additional polarizations will be computed and then constrained by existing GW data. Current signal analysis techniques will be tested to determine if they can mistakenly pick up an additional polarization, possibly leading us to misinterpret the signal, miss new physics, and misidentify source parameters. Additionally, the bias that originates from using the wrong model will be quantified. The second research focus of the project is to develop new models and data analysis software for future detector networks. This will include the first theory-agnostic waveform template with fully generic polarization content, as well as incorporating physics-informed additional polarizations into an unmodeled search software. Finally, existing visualizations in Virtual Reality (VR) will be expanded to allow predictions about the optimal configuration of detectors for polarization studies. In addition, the already successful Physics Outreach and Instruction through New Technologies (POINT) program will be expanded, and new free resources will be built to serve students in and around LA County. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.