Benevento, Giampaolo Raveri, Marco Lazanu, Andrei Bartolo, Nicola Liguori, Michele Brax, Philippe Valageas, Patrick

We investigate cosmological constraints on K-mouflage models of modified gravity. We consider two scenarios: one where the background evolution is free to deviate from $\Lambda$CDM (K-mouflage) and another one which reproduces a $\Lambda$CDM expansion (K-mimic), implementing both of them into the EFTCAMB code. We discuss the main observational sign...

Leloup, C. Ruhlmann-Kleider, V. Neveu, J. De Mattia, A.

The Galileon model is a tensor-scalar theory of gravity which explains the late acceleration of the Universe expansion with no instabilities and recovers General Relativity in the strong field limit. Most constraints obtained so far on Galileon model parameters from cosmological data were derived for the limited subset of tracker solutions and repo...

Gorji, Mohammad Ali Mukohyama, Shinji Firouzjahi, Hassan

It is well known that the standard scalar field mimetic cosmology provides a dark matter-like energy density component. Considering $SU(2)$ gauge symmetry, we study the gauge field extension of the mimetic scenario in spatially flat and curved FLRW spacetimes. Because of the mimetic constraint, the standard Yang-Mills term plays the role of the cos...

Grocholski, Oskar Kalinowski, Marcin Kolanowski, Maciej Renaux-Petel, Sébastien Turzyński, Krzysztof Vennin, Vincent

We study the geometrical instability arising in multi-field models of inflation with negatively-curved field space. We analyse how the homogeneous background evolves in presence of geometrical destabilisation, and show that, in simple models, a kinematical backreaction effect takes place that shuts off the instability. We also follow the evolution ...

Arbey, A. Coupechoux, J.-F.

Scalar fields are widely used in cosmology, in particular to emulate dark energy, for example in quintessence models, or to explain dark matter, in particular within the fuzzy dark matter model. In addition many scenarios involving primordial scalar fields which could have driven inflation or baryogenesis are currently under scrutiny. In this artic...

Martínez-Huerta, H. Biteau, J. Lefaucheur, J. Meyer, M. Pita, S. Vovk, I.

The Cherenkov Telescope Array (CTA) is the next generation ground-based observatory for $\gamma$-ray astronomy at energies above 30 GeV. Thanks to its unique capabilities, CTA observations will address a plethora of open questions in astrophysics ranging from the origin of cosmic messengers to the exploration of the frontiers of physics. In this no...

Frusciante, Noemi Perenon, Louis

The discovery of cosmic acceleration has triggered a consistent body of theoretical work aimed at modeling its phenomenology and understanding its fundamental physical nature. In recent years, a powerful formalism that accomplishes both these goals has been developed, the so-called effective field theory of dark energy. It can capture the behavior ...

Ignat’ev, Yu. G. Kokh, I. A.
Published in
Russian Physics Journal

A qualitative analysis of a cosmological model based on the asymmetric scalar doublet classical + phantom scalar field with minimal interaction is performed. It is shown that depending on the parameters of the model, the corresponding dynamical system can have 1, 3, or 9 stationary points corresponding to attractive or repulsive centers (1–5) and s...

Martin, Jérôme Vennin, Vincent

The Continuous Spontaneous Localisation (CSL) model solves the measurement problem of standard quantum mechanics, by coupling the mass density of a quantum system to a white-noise field. Since the mass density is not uniquely defined in general relativity, this model is ambiguous when applied to cosmology. We however show that some well-motivated c...

Chassande-Mottin, E. Leyde, K. Mastrogiovanni, S. Steer, D.A.

Gravitational waves from the coalescence of compact binaries, together with an associated electromagnetic counterpart, are ideal probes of cosmological models. As demonstrated with GW170817, such multimessenger observations allow one to use the source as a standard siren, analog of standard candles in conventional astronomy, in order to measure cos...