CAREER: Preparation Towards the Detection of a General Relativity Violation with Gravitational-Wave Observations

About This Grant

Over a century ago, Einstein revolutionized physics with his General Theory of Relativity (GR). This theory predicted gravitational waves --- ripples in the fabric of spacetime --- which can be observed through extreme cosmic events such as black hole collisions. Since the groundbreaking detection of gravitational waves in 2015 by two LIGO detectors in the US, about 100 similar events have been observed. These events offer a powerful testing ground for Einstein’s GR. Despite its success, the consensus is that GR is, at most, incomplete, representing an approximation to a more complete theory that cures some or all of its problems, much like Newtonian theory is an approximation to GR. A team of researchers at the University of Mississippi will apply advanced statistical methods to ensure that the tests of GR are accurate, carefully accounting for noise and unrelated effects to avoid false conclusions about the validity of the theory. The team will also develop a web-based tool with a basic introduction to gravitational-wave data, waves, and chirp with simple real-life examples. This tool will have features such that the user can change the masses of black holes in a binary and listen to the kind of chirping signal the merger produces. This tool aims to bring free-of-cost gravitational-wave science to everyone with an internet connection. The general theory of relativity (GR) is the most successful theory of gravity as it explains current astronomical observations and laboratory experiments. No statistically significant deviation from GR has been found yet. The improved sensitivities of LIGO, Virgo, and KAGRA detectors in the fourth and fifth observing runs will allow the detection of hundreds of compact binaries, revealing relativistic gravity in action in unprecedented detail and the potential to falsify GR. Due to the enormous success of GR in explaining observational and experimental results, the prior that the theory is correct is very high. It is, therefore, critical to know the extent to which current tests of GR are safe and when it is necessary to incorporate various systematics to confidently claim a GR violation. The goal of the study is twofold: First is to investigate the effect of non-stationary and non-Gaussian noise artifacts in the detector data, and black hole mimickers. This investigation will help the LIGO-Virgo-KAGRA (LVK) collaboration to account for a false alarm in the case of a statistically significant deviation from GR. The second goal is to assemble a set of criteria to classify a detection as anomalous that shows hints of GR violation. These anomalous detections will then be thoroughly investigated to determine if they truly exhibit GR violation or if they are artifacts of some kind of systematics. This set of criteria will eventually lead to a GR violation detection checklist, which will help the LVK collaboration to make an informed claim of GR violation if found in the data. The team will also develop a web-based self-learning app to teach gravitational-wave science to high school and undergraduate students. This tool will eliminate geographical barriers, allowing students from remote areas to access quality physics education. 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.