TY  - GEN
UR  - https://archiv.ub.uni-heidelberg.de/volltextserver/37056/
AV  - public
N2  - Motivated by the recent first detection of a gravitational wave signal, this dissertation reviews and develops analytical, numerical, and data analysis techniques to address the remaining blind spots in the current understanding of gravity.

    Beginning with the definition of asymptotically flat spacetimes and the mathematical framework of null geodesic congruences, the derivation of the shear tensor?as the carrier of the radiative content of the gravitational field?is revisited. This is followed by an application of the covariant phase space formulation of General Relativity to derive a non-conservation law associated with the symmetry group at null infinity in asymptotically flat spacetimes. This approach is shown to generalize previous formulations of the radiative phase space in General Relativity, recovering consistent results. The physical interpretation of these flux laws is then employed to derive constraint equations, which serve as the foundation for evaluating and comparing state-of-the-art numerical waveform models. This analysis yields novel insights into commonly used models and establishes a robust algorithm for assessing future improvements in waveform modeling.

    The flux laws are subsequently applied to compute quantum corrections to the gravitational waveform strain, arising from the gravitational wave echo effect. A detailed discussion of the echo effect is presented, with focus on two leading phenomenological scenarios involving echoes from binary black hole merger events. Both the original echo signal in the strain and quantum corrections to its nonlinear structure are analyzed for their potential observability by the future space-based LISA detector. The results indicate that the echo effect lies within LISA?s sensitivity range, and that the mission could potentially probe black hole area quantization through these measurements.

    Finally, in light of recent evidence towards a detection of a stochastic gravitational wave background from Pulsar Timing Array data, the theoretical motivation for such a background is reviewed. Several scenarios contributing significant astrophysical and cosmological components of this background are examined. This comprehensive study culminates in a forecast for the detection prospects of the gravitational wave background with the LISA instrument, using a modern, ready-to-use data analysis pipeline. The findings suggest that LISA will be capable of constraining the extra-galactic stochastic gravitational wave background to levels below a dimensionless spectral energy density of at least $\Omega_\T{GW} \lesssim 10^{-8}$.
CY  - Heidelberg
Y1  - 2025///
A1  - Maibach, David
ID  - heidok37056
TI  - Across the Horizon: On Gravitational Wave Flux Laws and Tests of Gravity
ER  -