Department Colloquium 

Gravitational Waves as Probes of Fundamental Physics and Gravity 

Alessandra Buonanno, Albert Einstein Institute 

Since the first detection of gravitational waves from a binary black-hole merger in 2015, the LIGO and Virgo detectors have observed about 100 gravitational-wave signals from mergers of black holes, neutron stars and their mixture. These observations rely on precise theoretical predictions of the relativistic two-body dynamics and gravitational radiation. After reviewing the synergetic approach that successfully combines analytical and numerical relativity to produce accurate waveform models, I will discuss the most compelling findings from the latest LIGO-Virgo observing run regarding astrophysics, gravity and fundamental physics. I will also highlight the bright future of gravitational-wave astronomy with the opening of new frequency bands on the ground (Einstein-Telescope/Cosmic Explorer) and in space (LISA) in the next decade, and the theoretical challenges and opportunities of developing high-precision waveform models to take full advantage of the discovery potential.