Speaker
Description
Predicted by general relativity, gravitational waves (GW) provide direct, observable signatures of strongly gravitating systems operating in extreme and often counterintuitive regimes of spacetime, including binary systems and black holes. Binary systems provide a unique means to probe how general relativity encodes spacetime curvature into observable GW signals. While the intrinsic emission of GWs from binaries is well understood, this thesis investigates a fundamental open question that extends beyond textbook GW physics: can external spacetime disturbances influence the evolution of a binary system, so much so that the GW may modify, quench, or even reverse the inspiral driven by the system’s own radiation?
The intrinsic orbital and radiative parameters of an equal-mass circular binary and their evolution are examined by deriving the GW spectrum within the quadrupole approximation of linearized general relativity. This includes the power spectrum P(ν)∝ν^(10/3), the energy spectrum ∣dE/dν∣∝ν^(-1/3), and the strain spectrum h(ν)∝ν^(2/3), along with their associated orbital decay (a ̇∝a^(-3)) and frequency evolution (ν ̇∝ν^(11/3)). These results are then benchmarked against observational data from the Hulse–Taylor binary pulsar to confirm their validity.
The response of a binary system to an incident gravitational wave is investigated using the geodesic deviation equation to model GW-induced tidal accelerations. The resulting energy transfer to the orbit is estimated by modeling the binary as a damped, driven harmonic oscillator, allowing for a frequency-dependent treatment of the absorbed power, considering both resonant and non-resonant driving frequencies. Under realistic conditions, external gravitational waves produce negligible orbital modifications compared to the binary’s intrinsic GW-driven inspiral.
| Keyword-1 | Gravitational Waves |
|---|---|
| Keyword-2 | Binary Systems |