-
Suddhasattwa Brahma23/06/2025 09:30
I will review recent results, and list outstanding challenges, of deriving an emergent cosmological spacetime from string-theoretic models. I will give a proposal for how a metric can be coarse-grained from abstract matrix degrees of freedom, and how one naturally gets a scale-invariant spectrum of primordial perturbations in this model, without introducing arbitrary tunable parameters, by...
Aller à la page de la contribution -
Yuki Yokokura23/06/2025 11:00
-
Adolfo Cisterna23/06/2025 14:00
-
Clara Montagnon23/06/2025 15:30
In the context of the general effort to model black hole dynamics, and in particular their return-to-equilibrium through quasi-normal modes, it is crucial to understand how much test-field perturbations deviate from physical perturbations in modified gravity scenarios. On the one hand, physical perturbations follow the modified Einstein equations of the considered extension of general...
Aller à la page de la contribution -
Antoine Vincenti23/06/2025 16:00
-
Simon Iteanu23/06/2025 16:30
-
Marios Petropoulos24/06/2025 09:30
Defining an energy-momentum tensor for asymptotically flat spacetimes seems to be of interest in its own right, or for possible holographic applications. That said, the role it could play is less clear than for anti de Sitter, bearing in mind that in the flat case an infinite number of data are needed on scri to reconstruct a solution. I will show that besides the Carrollian geometric...
Aller à la page de la contribution -
Wolfgang Wieland24/06/2025 11:00
-
Adrien Fiorucci24/06/2025 14:00
The main challenges in formulating a holographic correspondence for asymptotically flat spacetimes stem from the null nature of the conformal boundary and the non-conservation of gravitational charges in the presence of bulk radiation. In this talk, I will present the systematic and mathematically robust approach to understanding and deriving the associated flux-balance laws from geometric...
Aller à la page de la contribution -
Manuel Del Piano24/06/2025 15:30
Black holes provide a unique setting to explore quantum gravity, where semiclassical effects and quantum corrections can modify their observable properties. In this talk, I will present an effective metric approach to describe such effects in a model-independent way. The deformations of the metric are captured by a priori unknown functions of a physical observable of the spacetime, expressed...
Aller à la page de la contribution -
Johann Chevrier24/06/2025 16:00
In this presentation, we explore the structure of multipartite quantum entanglement through the lens of local unitary (LU) invariants. We begin with the bipartite case, where entanglement entropy admits a clear LU-invariant characterization via the Schmidt decomposition. We then extend the discussion to multipartite systems, where no canonical notion of spectrum exists and the classification...
Aller à la page de la contribution -
Aymeric Proust24/06/2025 16:30
String theory predicts extra spatial dimensions. The compactification of these extra dimensions give mass to particles. Knowing the spectrum of the particles is thus a central task to answer the question of which particle is observable. Moreover, to make sense of a lower-dimension theory one assumes that the extra dimensions are '' small ''. However, usually this is not the case, especially if...
Aller à la page de la contribution -
Jose Luis Jaramillo25/06/2025 09:30
The waveform of a binary black hole (BBH) coalescence appears to be both simple and universal. A natural question to ask is the following: is the BBH waveform “boring” or, rather, “elegant”? This talk is structured in two parts, a first one with a decidedly heuristic (and admittedly boldly ambitious) flavor and a second part in which ideas of the first part are cast in a more modest (but still...
Aller à la page de la contribution -
Silvia Nagy25/06/2025 11:00
I will show how the self-dual sector can be a useful tool to study asymptotic symmetries, and associated infinite algebras, both in flat space and in backgrounds relevant to cosmology.
Aller à la page de la contribution -
Antoine Rignon-Bret25/06/2025 14:00
-
Corentin Vitel25/06/2025 15:30
Black hole (BH) perturbation theory allows to decouple Einstein perturbative equations into wave-like master equations. In the spirit of a ”wave-mean flow” description of the dynamics, the background potential and master functions would be respectively cast as ”slow” and ”fast” degrees of freedom (DoF): the ”slow” DoF would underlie a nonlinear integrable dynamics (in the sense of isospectral...
Aller à la page de la contribution -
Valentine Maris25/06/2025 16:00
Noncommutative geometry provides a representation of space-time in terms of associative algebras of operators. The final goal is to end up with a "quantum space-time" which should encode quantum gravity effects at an effective level. Recently, the construction of such quantum space-times has been investigated and led to deformations of the usual Minkowski space-time.
Aller à la page de la contribution -
Jahanur Hoque26/06/2025 09:30
It is well-known that gravitational fields from an isolated system depend on the time varying quadrupole moment of the source. Quadrupole formula provides an estimate of the energy loss due to gravitational radiation. The first proposed quadrupole formula for gravitational waves in de Sitter was derived by Ashtekar, Bonga, Kesavan (ABK). We point out that a consistent quadrupolar truncation is...
Aller à la page de la contribution -
Quentin Vigneron26/06/2025 11:00
General relativity (GR) is equipped with one connection: the Levi-Civita connection of the Lorentzian metric. I will present a (parameter-free) modification of GR where a second affine connection dependent on the topology of the Universe is introduced. The presentation will be an overview of the motivations and consequences for cosmology of this framework. In particular, I will discuss the...
Aller à la page de la contribution -
Céline Zwikel26/06/2025 14:00
I will present a novel correspondence between the gravitational phase space at null infinity and the subleading phase space for finite-distance null hypersurfaces, such as black hole horizons. Using Newman-Penrose formalism and an off-shell Weyl transformation, this construction transfers key structures from asymptotic boundaries to null surfaces in the bulk—for instance, a notion of...
Aller à la page de la contribution -
Bernard RAFFAELLI26/06/2025 15:30
In this talk, I will present a recent conjecture about a Weyl's law for black hole quasinormal mode frequencies, that recovers the structural features of the standard Weyl's law for the eigenvalues of Laplacian-like operators in compact regions. More precisely, we propose that the asymptotic behavior of the counting function of quasinormal frequencies follows a power-law depending on the...
Aller à la page de la contribution
Choisissez le fuseau horaire
Le fuseau horaire de votre profil: