Theory2021 GW

1. What are the two ways to derive the wave equation from the Einstein equations? How does gauge fixing come in?
2. What is the TT gauge? What are the solutions for gravitational waves in that gauge? What are their main properties?
3. What are the main properties of gravitational waves in an expanding universe? How does the expansion affect the wave equation? What are the potential consequences?
4. Give the expression of the gravitational wave far away from a source as a function of the leading multipole moment of the source. Explain why the lower-order multipoles do not contribute.
5. What steps are necessary to derive the expression of the chirp mass and of the waveform during an inspiral at the leading order in [math]\displaystyle{ v/c }[/math]?
6. What is the effect of a gravitational wave on a Michelson interferometer? Discuss the situation in the TT gauge and in the proper frame of the detector.