Related papers: On the Nonlocal Newtonian Cosmology
General Relativity, despite its century-long success, faces conceptual and observational challenges, including singularities, incompatibility with quantum mechanics, and the need to introduce dark matter and dark energy. Precision cosmology…
Non-local gravity terms have a relevant role in determining the cosmological dynamics. Here we consider curvature- and torsion-based cosmological models where non-local terms can be ``scalarised'' and then reduced under the standard of…
We introduce a cosmological model in the framework of Generalised Massive Gravity. This theory is an extension of non-linear massive gravity with a broken translation symmetry in the St\"uckelberg space. In a recent work, we showed the…
The observations of SNIa suggest that we live in the acceleration epoch when the densities of the cosmological constant term and matter are almost equal. This leads to the cosmic coincidence conundrum. As the explanation for this problem we…
The Brown-York quasilocal energy is applied to three cosmological problems which have previously been studied with the Hawking-Hayward quasilocal energy (Newtonian simulations of large scale structure formation, turnaround radius in the…
We model the cosmic medium as the mixture of a generalized Chaplygin gas and a pressureless matter component. Within a neo-Newtonian approach (in which, different from standard Newtonian cosmology, the pressure enters the homogeneous and…
We investigate the cosmological perturbation dynamics for a universe consisting of pressureless baryonic matter and a viscous fluid, the latter representing a unified model of the dark sector. In the homogeneous and isotropic background the…
We perform numerical evolutions of cosmological scenarios using a standard general relativistic code in spherical symmetry. We concentrate on two different situations: initial matter distributions that are homogeneous and isotropic, and…
We identify a time-dependent class of metrics with potential applications to cosmology, which emerge from negative-tension branes. The cosmology is based on a general class of solutions to Einstein-dilaton-Maxwell theory, presented in…
The evolution of nonlinear density fluctuations around the Jeans mass shortly after cosmological recombination is analyzed using a 3D hydrodynamics/dark--matter code. The Cosmic Background Radiation (CBR) exerts Compton friction on free…
We analyze cosmic microwave background (CMB) data to constrain the mass and interaction strengths of thermally-produced dark matter (DM) in a self-consistent manner, simultaneously taking into account the cosmological effects of its mass…
We show how generic off--diagonal cosmological solutions depending, in general, on all spacetime coordinates can be constructed in massive gravity using the anholonomic frame deformation method. Such metrics describe the late time…
Modern cosmology presents important challenges such as the \textit{Hubble tension}, \textit{El Gordo's collision} or the \textit{impossible galaxies} ($z > 10$). Slight modifications to the standard model propose new parameters (e.g. the…
We examine the fully relativistic evolution of cosmic voids constituted by baryons and cold dark matter (CDM), represented by two non-comoving dust sources in a $\Lambda$CDM background. For this purpose, we consider numerical solutions of…
A host of dark energy models and non-standard cosmologies predict an enhanced Hubble rate in the early Universe: perfectly viable models, which satisfy Big Bang Nucleosynthesis (BBN), cosmic microwave background and general relativity…
Theoretical predictions from a modified theory of gravity with a nonminimal coupling between matter and curvature are compared to data from recent cosmological surveys. We use type Ia supernovae data from the Pantheon+ sample and the recent…
Non-baryonic, or "dark," matter is believed to be a major component of the total mass budget of the universe. We review the candidates for particle dark matter and discuss the prospects for direct detection (via interaction of dark matter…
Dark matter cannot be observed directly, but its weak gravitational lensing slightly distorts the apparent shapes of background galaxies, making weak lensing one of the most promising probes of cosmology. Several observational studies have…
We provide a systematic and updated discussion of a research line carried out by our group over the last few years, in which gravity is modified at cosmological distances by the introduction of nonlocal terms, assumed to emerge at an…
We investigate the cosmological behavior in a universe governed by time asymmetric extensions of general relativity, which is a novel modified gravity based on the addition of new, time-asymmetric, terms on the Hamiltonian framework, in a…