Levinson, Amir Cerutti, Benoît

We investigate the dynamics and emission of a starved magnetospheric region (gap) formed in the vicinity of a Kerr black hole horizon, using a new, fully general relativistic particle-in-cell code that implements Monte-Carlo methods to compute gamma-ray emission and pair production through the interaction of pairs and gamma rays with soft photons e...

De Felice, Antonio Langlois, David Mukohyama, Shinji Noui, Karim Wang, Anzhong

We consider Higher-Order Scalar-Tensor theories which appear degenerate when restricted to the unitary gauge but are not degenerate in an arbitrary gauge. We dub them U-degenerate theories. We provide a full classification of theories that are either DHOST or U-degenerate and that are quadratic in second derivatives of the scalar field, and discuss...

García-García, Carlos Linder, Eric Ruíz-Lapuente, Pilar Zumalacárregui, Miguel

The possibility of linking inflation and late cosmic accelerated expansion using the $\alpha$-attractor models has received increasing attention due to their physical motivation. In the early universe, $\alpha$-attractors provide an inflationary mechanism compatible with Planck satellite CMB observations and predictive for future gravitational wave...

Ben Achour, Jibril Lamy, Frédéric Liu, Hongguang Noui, Karim

We consider the modified Einstein equations obtained in the framework of effective loop quantum gravity for spherically symmetric space-times. When one takes into account (only point-wise holonomy) quantum corrections, the deformation of Einstein equations is parametrized by a function f(x) of one variable . We solve explicitly these equations for ...

Broadhurst, Tom Diego, Jose Smoot, George

Gravitational waves can be focussed by the gravity of an intervening galaxy, just like light, thereby magnifying binary merging events in the far Universe. High magnification by galaxies is found to be responsible for the brightest sources detected in sky surveys, but the low angular resolution of LIGO/Virgo is insufficient to check this lensing po...

Breton, Michel-Andrès Rasera, Yann Taruya, Atsushi Lacombe, Osmin Saga, Shohei

The apparent distribution of large-scale structures in the universe is sensitive to the velocity/potential of the sources as well as the potential along the line-of-sight through the mapping from real space to redshift space (redshift-space distortions, RSD). Since odd multipoles of the halo cross-correlation function vanish when considering standa...

Deruelle, Nathalie Merino, Nelson Olea, Rodrigo

In this paper we show how to translate into tensorial language the Chern-Weil theorem for the Lorentz symmetry, which equates the difference of the Euler densities of two manifolds to the exterior derivative of a transgression form. For doing so we need to introduce an auxiliary, hybrid, manifold whose geometry we construct explicitely. This allows...

Cusin, Giulia Dvorkin, Irina Pitrou, Cyril Uzan, Jean-Philippe

We present the first predictions for the angular power spectrum of the astrophysical gravitational wave background constituted of the radiation emitted by all resolved and unresolved astrophysical sources. Its shape and amplitude depend on both the astrophysical properties on galactic scales and on cosmological properties. We show that the angular ...

Desmond, Harry Ferreira, Pedro Lavaux, Guilhem Jasche, Jens

Extensions of the standard models of particle physics and cosmology may lead to the presence of long-range fifth forces whose strength and range depend on gravitational environment. Fifth forces on astrophysical scales are best studied in the cosmic web where perturbation theory breaks down. We present precision constraints on a symmetron- or chame...

Duval, Christian Pasquet, Johanna Schucker, Thomas Tilquin, Andre

We compute the birefringence of light in curved Robertson-Walker spacetimes and propose an exotic formula for redshift based on the internal structure of the spinning photon. We then use the Hubble diagram of supernovae to test this formula.