Arbey, A. Coupechoux, J.-F

Scalar fields appear in many cosmological models, in particular in order to provide explanations for dark energy and inflation, but also to emulate dark matter. In this paper, we show that it is possible for a scalar field to replace simultaneously dark matter, dark energy and inflation by assuming the existence of a non-minimal coupling to gravity...

Palmese, A. Devicente, J. Pereira, M.E.S. Annis, J. Hartley, W. Herner, K. Soares-Santos, M. Crocce, M. Huterer, D. Magaña Hernandez, I.
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We present a measurement of the Hubble constant $H_0$ using the gravitational wave (GW) event GW190814, which resulted from the coalescence of a 23 $M_\odot$ black hole with a 2.6 $M_\odot$ compact object, as a standard siren. No compelling electromagnetic counterpart with associated host galaxy has been identified for this event, thus our analysis...

Garcia, A. Morgan, R. Herner, K. Palmese, A. Soares-Santos, M. Annis, J. Brout, D. Vivas, A.K. Drlica-Wagner, A. Santana-Silva, L.
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We present the results from a search for the electromagnetic counterpart of the LIGO/Virgo event S190510g using the Dark Energy Camera (DECam). S190510g is a binary neutron star (BNS) merger candidate of moderate significance detected at a distance of 227$\pm$92 Mpc and localized within an area of 31 (1166) square degrees at 50\% (90\%) confidence....

dimitrijevic, ivan dragovich, branko koshelev, alexey s. rakic, zoran stankovic, jelena

In this paper, we investigate a nonlocal modification of general relativity (GR) with action S = 1 16 &pi / G &int / [ R &minus / 2 &Lambda / + ( R &minus / 4 &Lambda / ) F ( □ ) ( R &minus / 4 &Lambda / ) ] &minus / g d 4 x , where F ( □ ) = &sum / n = 1 + &infin / f n □ n is an analytic function of the d&rsquo / Alembertian □. We found a few exac...

Leloup, Clément Ruhlmann-Kleider, Vanina Neveu, Jeremy de Mattia, Arnaud

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...

Zumalacarregui, Miguel

Discrepant measurements of the Universe's expansion rate ($H_0$) may signal physics beyond the standard cosmological model. Here I describe two early modified gravity mechanisms that reconcile the value of $H_0$ by increasing the expansion rate in the era of matter-radiation equality. These mechanisms, based on viable Horndeski theories, require si...

Anchordoqui, Luis A. Antoniadis, Ignatios Lüst, Dieter Soriano, Jorge F.

It was recently pointed out that the existence of dark energy imposes highly restrictive constraints on effective field theories that satisfy the Swampland conjectures. We provide a critical confrontation of these constraints with the cosmological framework emerging from the Salam-Sezgin model and its string realization by Cvetic, Gibbons, and Pope...

Yousaf, Z. Khlopov, Maxim Yu. Bhatti, M.Z. Naseer, T.

The aim of this paper is to generalize the definition of complexity for the static self-gravitating structure in $f(R,T,Q)$ gravitational theory, where $R$ is the Ricci scalar, $T$ is the trace part of energy momentum tensor and $Q\equiv R_{\alpha\beta}T^{\alpha\beta}$. In this context, we have considered locally anisotropic spherical matter distri...

Crisostomi, Marco Lewandowski, Matthew Vernizzi, Filippo

We study perturbation theory for large-scale structure in the most general scalar-tensor theories propagating a single scalar degree of freedom, which include Horndeski theories and beyond. We model the parameter space using the effective field theory of dark energy. For Horndeski theories, the gravitational field and fluid equations are invariant ...

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 ...