Related papers: Viable f(T) models are practically indistinguishab…
Recent studies indicate that, near equilibrium condition could not be maintained for bulk viscous matter models during the accelerated expansion of the universe in the context of Einstein's gravity, without including the cosmological…
This thesis investigates late-time cosmic acceleration using modified gravity theories with a focus on $f(Q)$ gravity, as an alternative to the $\Lambda$CDM model. The standard cosmological model attributes the acceleration to a…
We propose a new framework for studying the cosmology of $f(R)$ gravity which completely avoids using the reconstruction programme. This allows us to easily obtain a qualitative feel of how much the $\Lambda$CDM model differs from other…
The problem of reproducing dark energy effects is reviewed here with particular interest devoted to cosmography. We summarize some of the most relevant cosmological models, based on the assumption that the corresponding barotropic equations…
We perform N-body simulations for $f(T)$ gravity using the ME-Gadget code, in order to investigate for the first time the structure formation process in detail. Focusing on the power-law model, and considering the model-parameter to be…
We study the dynamics of the FLRW flat cosmological models in which the vacuum energy varies with time, $\Lambda(t)$. In this model we find that the main cosmological functions such as the scale factor of the universe and the Hubble flow…
We explore the cosmological implications of five modified gravity (MG) models by using the recent cosmological observational data, including the recently released SNLS3 type Ia supernovae sample, the cosmic microwave background anisotropy…
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 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…
A recently proposed technique allows one to constrain both the background and perturbation cosmological parameters through the distribution function of supernova Ia apparent magnitudes. Here we extend this technique to alternative…
The accelerating expansion of our universe at present could be driven by an unknown energy component (Dark Energy) or a modification of general relativity (Modified Gravity). In this note we revisit the constraints on a phenomenological…
We constrain two non-flat time-evolving dark energy cosmological models by using Hubble parameter data, Type Ia supernova apparent magnitude measurements, and baryonic acoustic oscillation peak length scale observations. The inclusion of…
The LCDM cosmological model assumes the existence of a small cosmological constant in order to explain the observed accelerating cosmic expansion. Despite the dramatic improvement of the quality of cosmological data during the last decade…
In this work, we investigate a cosmological scenario with a time-dependent cosmological constant $\Lambda$(t) within the spatially flat Friedmann-Lema\^itre-Robertson-Walker (FLRW) framework. Here we study a power-law $\Lambda(t)$CDM model…
Instead of assuming a form of gravity and demand cosmology fit with $\Lambda CDM$, a potentially `viable' $f(R)$ gravity model is derived assuming an alternative model of cosmology. Taking the `designer' approach to $f(R)$, a new class of…
We use updated Hubble parameter and baryon acoustic oscillation data, as well as other lower-redshift Type Ia supernova, Mg II reverberation-measured quasar, quasar angular size, H II starburst galaxy, and Amati-correlated gamma-ray burst…
The observed accelerated expansion of the Universe may be explained by dark energy or the breakdown of general relativity (GR) on cosmological scales. When the latter case, a modified gravity scenario, is considered, it is often assumed…
Nonlocal massive gravity can provide an interesting explanation for the late-time cosmic acceleration, with a dark energy equation of state $w_{\rm DE}$ smaller than $-1$ in the past. We derive the equations of linear cosmological…
The $f(R)$ theory of gravitation developed perturbatively around the general theory of relativity with cosmological constant (the \text{$\Lambda$}CDM model) in a flat FLWR geometry is considered. As a result, a general explicit cosmological…
In this work, we examine viable models of $f(Q,T)$ gravity theories against observational data with the aim to constrain the parameter space of these models. We have analysed five different models of $f(Q,T)$ gravity and tested them against…