Cosmic Inflation explains the initial conditions of the history of the Universe and generates the density perturbations which lead to the formation of structures in the Universe, such as galaxies. Dark Energy can be thought of as a substance responsible for a late-time inflationary period, in which the Universe has entered relatively recently. In this talk I will discuss inflation and dark...
We analyse the emergent cosmological dynamics corresponding to the mean field hydrodynamics of quantum gravity condensates, in the tensorial group field theory formalism. We focus in particular on the cosmological effects of fundamental interactions, and on the contributions from different quantum geometric modes. The general consequence of such interactions is to produce an accelerated...
In this talk, we will present a renormalizable polynomial inflation model, focusing on the small field scenario. We show that the CMB data can be fitted perfectly with a perturbated inflection-point. In particular, the running of the spectral index is predicted to be $\alpha \simeq -1.43 \times 10^{-3}$, which could be tested by next generation CMB experiment. We also analyze reheating...
In this work, we present two models to describe early dark energy, with a non-negligible contribution in the radiation-domination epoch. Such type of early contributions to the Hubble parameter is extremely promising to tackle the ongoing Hubble tension. With this motivation, we explore the redshift evolution of their state equations and evaluate the best fits for the models' free parameters,...
In this work, we explore the construction of a vector-tensor theory with a SU(2) global symmetry in the vector sector as a proposal for a modified theory of gravity. We start with a general Lagrangian containing terms involving symmetric and antisymmetric combinations of the covariant derivatives of the field. Then, we study the degeneracy of the full theory to determine whether it can be...
The scalar-tensor theory introduced by Horndeski has a sound and firm basis since it avoids the Ostrograski’s instability. The generalized SU(2) Proca Theory, which is a vector-tensor theory where the vector content enjoys a SU(2) global symmetry, has been built following Horndeski’s spirit. Such a theory exhibits interesting properties that make it a candidate to describe the primordial...
Recently, theories based on multiple vector fields have been proposed, involving not only the dynamical character, as commonly demanded, but also the interaction between them; however, it is a topic that has not brought enough attention in the construction of alternative theories of gravity until a few years ago. Furthermore, in the construction of theories with multiple fields, the...
Motivated by the work of Saridakis, in this talk we report the phenomenology of Barrow holographic dark energy using the Granda-Oliveros infrared cutoff. The latter is a holographic dark energy model based on the recently proposed Barrow entropy, which arises from the modification of the black-hole surface due to quantum-gravitational effects, quantified by a new parameter $\Delta$. In order...
NANOGrav (the North American Nanohertz Observatory for Gravitational Waves) exploits the high-precision timing of an array of Galactic millisecond pulsars (MSPs) in a bid to unveil timing deviations induced by gravitational waves (GWs). A GW transiting an Earth–pulsar line of sight distorts the intervening spacetime, causing pulses to arrive before or after their expected times of arrival...
I will present the cosmological results from the Dark Energy Survey analysis of data collected over three years, the so-called DES-Y3 data. These results arise from studying three combinations of two-point angular correlation functions (the so-called 3x2pt analysis) involving the distribution of galaxies and the distortions in their images due to weak gravitational lensing, as well as the...
Cosmological constraints of Modified Gravity (MG) models are seldom carried out rigorously. First, even though general MG models evolve differently (i.e., background and perturbations) to the standard cosmological model, it is usual to assume a ΛCDM background. This treatment is not correct and in the era of precision cosmology could induce undesired biases in cosmological parameters. Second,...
The work is devoted to the study of bouncing cosmology in f(R, T) modified gravity
where we presume f(R, T) = R + 2λT, with R the Ricci scalar, T the trace of energy momentum
tensor and λ the model parameter. We present here a novel parametrization of Hubble parameter which is apt in representing a successful bouncing scenario undergoing no singularity. We
proceed to present a complete...
We study the thermodynamical behavior of Banks-Zaks theory close to its infrared fixed point in a cosmological setting. Due to the anomalous dimension, the resulting pressure and energy density deviate from radiation and result in various cosmological scenarios. For the specific range of parameters, unparticles alone results in an exponentially contracting universe followed by a non-singular...
In the context of the study of large-scale structure of the Universe, we analyze the response of cosmic void clustering to selection effects, such as angular incompleteness due to observational systematics and radial selection functions. We find for the case of moderate (<20%) incompleteness: that void sample selection based on a constant radius cut yields robust measurements. This is...
Los métodos cosmografícos son una técnica independiente de los modelos cosmológicos, que
es utilizada para reconstruir la expansión de Hubble del Universo con bajos corrimientos al rojo.
En este trabajo se hace un análisis cosmográfico, considerando ajuste lineal, cuadrático y cúbico, de las distancias
de luminosidad de supernovas tipo Ia. Para ello se toman los datos de corrimiento al...
En este trabajo se implementan diferentes algoritmos de aprendizaje supervisado y no supervisado en la clasificación de exoplanetas usando la base de datos de los archivos de exoplanetas de la NASA. Los dos atributos usados para la clasificación de exoplanetas son el radio y la masa de los mismos, los cuales nos permiten clasificarlos en 4 categorı́as: Gigantes Gaseosos, Tipo Neptuno, Super...
La formación de estructuras a gran escala en el universo es un área de gran interés científico en cosmología, en cuyo estudio diversas herramientas estadísticas ayudan a evaluar los modelos analíticos que describen el origen y evolución de estructuras. Para ello se presente la estimación de la función de correlación de dos puntos en el campo de materia sobre los resultados de la simulación...
Inflation and dark energy share many essential properties. I will describe how these two eras can be easily unified into a common framework based on emergent scale invariance. I will present the associated cosmological history and discuss how the inclusion of non-minimally coupled spectator fields may lead to the spontaneous symmetry breaking of internal symmetries and its eventual restoration...
21cm radio signal has emerged as an important probe in investigating the dark age of the Universe (recombination to reionization). In the current analysis, we explore the combined effects of primordial black holes (PBH), cooling off of the baryonic matter due to dark matter (DM) - baryon collisions and interaction of dark matter - dark energy (DE) fluid on the 21cm brightness temperature. The...
We study possible particle-antiparticle asymmetry in the dark sector in two distinct scenarios. In both the scenarios dark matter (DM) scatterings play defining role in deciding the asymmetry as well as the density. In the first case, we demonstrate a general semi-annihilation of DM particles, leading to maximal asymmetry in DM sector (Ref :JHEP 08 (2020), 149). In the second case, We find an...
Hawking radiation (HR) causes ultralight primordial black holes (PBHs) ($≤ 10^9g$) to
entirely evaporate and produce all of the particles in a given theory, regardless of their
other interactions. Successful baryogenesis via leptogenesis predicts the mass scale of RH
neutrinos as well as black holes if right-handed (RH) neutrinos are also created from PBH
evaporation. We show that a...
The E989 experiment at the Fermi National Laboratory (FNAL) reported a 4.2-sigma discrepancy between the measured magnetic dipole moment of the muon, and the prediction from the Standard Model (SM). Addressing this anomaly could require a proper accounting of QCD hadronic vacuum polarizations, or it might be a signal of new physics. In this talk, we shall take the latter approach and propose a...
The existence of dark matter is firmly established from various observations in Cosmology, Astrophysics, and Particle physics. However, most experiments trying to discover the building blocks of dark matter assume additional channels that allow interactions with baryonic matter, as pure gravitational effects are extremely difficult to detect. This assumption, however, is not yet backed by...
We show that the type-I seesaw, responsible for generating the light neutrino mass, itself is capable of accommodating one of the three right-handed neutrinos as a freeze-in type of dark matter (DM) where the required smallness of the associated coupling is connected to the lightness of the (smallest) active neutrino mass. It turns out that (a) the non-thermal production of DM having mass...
We study axion dark matter production from a misalignment mechanism in scenarios featuring a general nonstandard cosmology. Before the onset of Big Bang nucleosynthesis, the energy density of the universe is dominated by a particle field $\phi$ described by a general equation of state $\omega$. The ensuing enhancement of the Hubble expansion rate decreases the temperature at which axions start...
We investigate the production of QCD axion dark matter in a nonstandard cosmological era triggered by primordial black holes (PBHs) that fully evaporate before the onset of BBN. Even if PBHs cannot emit the whole axion dark matter abundance through Hawking radiation, they can have a strong impact on the dark matter produced via the misalignment mechanism. First, the oscillation temperature of...
