Past Events
April 2025 | |
| Tue 15 Apr 2025 14:00 - 15:00 |  Seminar: GAnG seminar - Molly KaplanCentre for Geometry, Analysis and Gravitation Title - De Sitter quantum gravity and the emergence of local algebras Abstract - Quantum theories of gravity are generally expected to have some degree of nonlocality, with familiar local physics emerging only in a particular limit. Perturbative quantum gravity around backgrounds with isometries and compact Cauchy slices provides an interesting laboratory in which this emergence can be explored. In this context, the remaining isometries are gauge symmetries and, as a result, gauge-invariant... |
| Tue 8 Apr 2025 14:00 - 15:00 | Seminar: GAnG seminar - Sadra Jazayeri - POSTPONED - NEW DATE TBC Centre for Geometry, Analysis and Gravitation |
| Tue 1 Apr 2025 14:00 - 15:00 | Seminar: GAnG seminar - Betti Hartmann, Black holes and boson stars with wavy scalar hair Centre for Geometry, Analysis and Gravitation Black holes and boson stars with wavy scalar hair Static, spherically symmetric black holes can carry scalar hair when coupling standard Einstein gravity minimally to a self-interacting complex scalar field and a U(1) gauge field. For this scalar hair to exist, the frequency of the scalar field needs to be fine-tuned. In this talk, I will discuss these solutions and point out that for sufficiently large gravitational coupling, the space-time splits into two distinct parts: (a) an inflating... |
March 2025 | |
| Tue 25 Mar 2025 14:00 - 15:00 | Seminar: GAnG seminar - David Nielsen, Gravitational wave science in the next decade: a new frontier for numerical relativity Centre for Geometry, Analysis and Gravitation Gravitational wave science in the next decade: a new frontier for numerical relativity. The newly upgraded LIGO and Virgo observatories are regularly detecting gravitational waves from merging black holes and neutron stars, with public alerts for candidate events coming at a rate of about one per day. These observations provide new information about the population of black holes in the near universe, giving clues about their formation and history, and they allow us to test general relativity... |
| Tue 18 Mar 2025 14:00 - 15:00 | Seminar: GAnG seminar - Calvin Chen (rescheduled) Deformations of Extremal Black Holes Centre for Geometry, Analysis and Gravitation Title: Deformations of Extremal Black Holes Abstract: In this talk, I will re-examine a class of extremal charged black holes in AdS and study their EFT corrections. I will start by introducing static perturbations to the near-horizon geometry of extremal black holes. It turns out these generically suffer from singularities of various degrees. Particular deformations are marginal – they are not singular in GR, but even arbitrarily small EFT corrections seem to be able to make them... |
| Tue 11 Mar 2025 14:00 - 15:00 | Seminar: GAnG seminar - Christopher Couzens
Localising Romans Supergravity Centre for Geometry, Analysis and Gravitation Localising Romans Supergravity In this talk, I will discuss how Equivariant Localization can be used to compute observables in supergravity without the need to solve the equations of motion. We will use 6d Romans supergravity as our test case and show that the on-shell action is almost completely determined in terms of topological data. This allows us to recover known results in the literature and to make predictions for hitherto unknown solutions. |
February 2025 | |
| Tue 25 Feb 2025 14:00 - 15:00 | Seminar: GAnG seminar - Martin Taylor, Radiative properties of collisionless matter in isolated charged systems Centre for Geometry, Analysis and Gravitation Radiative properties of collisionless matter in isolated charged systems The Vlasov--Poisson system describes the evolution of an ensemble of either: 1. Electrically charged particles, interacting via an electrostatic Coulomb force; 2. Self-gravitating particles, interacting via a Newtonian gravitational force. In 3 space dimensions, for isolated systems, dispersive solutions asymptotically exhibit logarithmically corrected linear behaviour, i.e. such solutions ``scatter'' in a... |
| Tue 18 Feb 2025 14:00 - 15:00 | Seminar: GAnG seminar - Joshua Daniels Holgate Centre for Geometry, Analysis and Gravitation Title: Mean curvature flow from conical singularities Abstract: We discuss some regularity results for mean curvature flow from smooth hypersurfaces with conical singularities. We then discuss how to use these results to tackle the conical singularity resolution conjecture of Ilmanen, demonstrating a non-uniqueness dichotomy: a closed flow encountering a conical singularity 'fattens' if and only if the asymptotic cone also fattens. This is joint work with Otis Chodosh and Felix Schulze. |
| Tue 11 Feb 2025 14:00 - 15:00 | Seminar: GAnG seminar - Thomas Spieksma
Black hole environments: a landscape of possibilities Centre for Geometry, Analysis and Gravitation Title: Black hole environments: a landscape of possibilities Abstract: Black holes in our Universe are not expected to be in vacuum. Different black hole environments include accretion disks, dark matter spikes or superradiant boson clouds. In binary systems, these environments could be probed by future space-based gravitational wave interferometers. Understanding their impact is crucial--not only for detecting the gravitational wave signal in the first place but also for uncovering new... |
| Tue 4 Feb 2025 14:00 - 15:00 |  Seminar: GAnG seminar - Juan Valiente Kroon Inaugural Professorial Lecture
Asymptotics in General Relativity: the role of spatial infinityCentre for Geometry, Analysis and Gravitation Asymptotics in General Relativity: the role of spatial infinity In this overview talk I will discuss the relation between the asymptotic behaviour of the gravitational at null infinity and spatial infinity ¾the so-called problem of spatial infinity. I will argue that the conditions assumed by Penrose in his programme to study isolated systems in General Relativity are too restrictive to describe generic spacetimes. I will also discuss how a conformal approach to the study of the structure of... |
January 2025 | |
| Tue 21 Jan 2025 14:00 - 15:00 | Seminar: GAnG seminar - Lashi Bandara Centre for Geometry, Analysis and Gravitation Title: Harmonic analysis and boundary value problems in geometry Abstract: Historically, boundary value problems have appeared in engineering problems as partial differential equations on structures with boundary. However, in the past half century, differential operators have played a crucial role to encode, understand and resolve geometric and topological questions. This often requires the deformation of boundary conditions and harnesses index theory as a control mechanism through utilising... |