Strong Gravity

GW250114, with a signal-to-noise ratio of ∼80, enables the most precise single-event tests of strong-field gravity to date: setting the tightest constraints on deviations from general relativity, delivering the cleanest ringdown measurement yet, and placing stringent bounds on compact object…

Within the Effective Field Theory approach to gravity, deviations from General Relativity can be systematically described by higher-curvature operators. However, computing the resulting corrections to black hole quasinormal mode spectra remains challenging in the rapidly rotating regime, where…

Gravitational-wave observations by LIGO and Virgo are revealing a population of merging stellar-mass binary black holes. Thus far, the broad connection between the inferred population and the physics that underlies black hole formation remains elusive. The O4a run of the LVK has more than doubled…

Neutron stars are ultra-dense remnants of massive stellar cores, observable across the electromagnetic spectrum. Their emission reflects a delicate interplay of magnetic, thermal, and structural processes under extreme conditions of density, temperature, and magnetic fields—regimes unattainable in…

Since the detection of GW150914 a decade ago, ground based gravitational wave detectors have detected hundreds of compact binary coalescences, offering myriad insights into the universe. These include precise measurements of the masses and spins of compact objects, as well as searches for phenomena…

Tidal disruption events — where an unfortunate star is destroyed by a previously quiescent supermassive black hole — offer a unique probe of the low mass end of the supermassive black hole population. Recent observational advances have lead to the discovery of ~100 such events, many of which are…

The detection of gravitational waves from binary black hole mergers enables us to observe the behavior of spacetimes in the strong-field, highly dynamical regime. The LIGO–Virgo–KAGRA collaboration has now observed hundreds of such events, offering several exciting candidates with differing…

I will revisit the canonical quantization of General Relativity in the self-dual formulation in the presence of a cosmological constant, discussing the normalizability of graviton states over the de Sitter spacetime. Time permitting, I will explain how the physics of the Hamiltonian constraint is…

Gravitational waves (GW) from compact binaries provide excellent opportunities for testing general relativity (GR) in the strong- and dynamical-field regime. So far, inspiral-based tests have mostly assumed smooth deviations from GR within a post-Newtonian description, thereby overlooking certain…

Current waveform models of binary black hole mergers incorporate a large amount of analytical information during the inspiral phase. In contrast, post-merger descriptions typically rely on phenomenological ansätze informed by numerical relativity, with the quasi-normal mode frequencies providing the…

In general relativity, sufficiently small bodies are idealized as test particles moving along geodesics of the background spacetime. This picture becomes inadequate, however, once the object’s own gravitational field is taken into account. The self-force program resolves this by showing that compact…

Current gravitational-wave observatories — LIGO, Virgo, and KAGRA — have made phenomenal new discoveries that are already making waves in a range of fields from fundamental physics to cosmology. Yet the era of gravitational-wave astronomy is still at its dawn. The next generation of ground-based…