Conveners
Day 3: Cosmological reconstruction and early-universe gravitational waves
- Dong-Gang Wang (HKUST)
Day 3: Black-Hole Hair, Superradiance, and Ringdown
- Shi Pi (Institute of Theoretical Physics, Chinese Academy of Sciences)
Day 3: Closing Perspective on Gravity and Cosmology
- There are no conveners in this block
The standard cosmological model is under increasing observational pressure. Persistent tensions in the Hubble constant and the growth of structure suggest either unaccounted systematics or genuine new physics beyond ΛCDM — and distinguishing between these possibilities demands data analysis methods that do not smuggle in theoretical priors through the back door. In this talk, I present a...
Recent high-cadence observations by Subaru-HSC have identified a population of ultrashort-timescale microlensing events, providing a compelling window for planet-mass primordial black holes (PBHs) to constitute the entirety of dark matter. In this Letter, we demonstrate that this PBH population and the nanohertz stochastic gravitational-wave (GW) background reported by pulsar timing arrays...
In this talk, I will first introduce our recent progress in first-order phase transitions, in particular, generations of density perturbations, formations of PBHs, associated scalar-induced gravitational waves, and productions of sound waves from gravitational instability.
We investigate the superhorizon behavior of scalar hair sourced by black holes in de Sitter spacetime in the linearly coupled shift-symmetric scalar--Gauss--Bonnet theory. This hair exhibits both spatial and temporal growth, which has been suggested to be problematic. We show that this growth is expected, as it is not a special consequence of the black hole, but instead follows from the...
Black hole perturbation theory is a cornerstone of gravitational wave science, providing a powerful framework to test General Relativity in the strong-field regime and to characterize the final remnant of a binary merger. The final "ringdown" phase, where the newly formed black hole settles into its stationary state, is a particularly clean probe of its fundamental properties. In this talk, I...
Rotating black holes can form dense boson clouds through superradiant instability, making Kerr black holes a powerful probe of ultralight massive bosons. Previous studies of black hole superradiance have often treated bosonic fields classically, leaving open questions about how particles are produced and how the clouds grow over time. In this work, we canonically quantize a massive scalar...
I will talk about various topics in gravity and cosmology which I have been studying through my academic life, and discuss my personal perspectives.
