The large upcoming spectroscopic surveys like DESI and Euclid will enable a very precise measurement of the matter power spectrum and bispectrum on a vast range of scales. I will discuss how this precision can be improved with the combined use of galaxies and standard candles as tracers of the matter and velocity fields. I will show the benefits of using either supernovae or bright standard...
In the near future, forthcoming Large-Scale Structure (LSS) missions such as the DESI, eROSITA, Euclid, WFIRST , and LSST are poised to survey extensive cosmological volumes, collecting terabytes of data that promise to enhance our understanding of cosmological parameters with unprecedented precision. To achieve this ambitious objective, it is crucial to extract the maximum amount of...
Understanding the expansion of the universe is the top priority of all space agencies. In this talk, we will discuss the primary cosmological observables capable of shedding light on these mysterious phenomena. We will also focus on the intense efforts that the European Space Agency is undertaking to understand the nature of accelerated expansion. In particular, we will present the Euclid Satellite.
The Lyman alpha forest measured from the spectra of high-redshift quasars observed with DESI will provide a wealth of information for cosmology. It will allow us to unveil the expansion history with great precision by measuring the BAO scale at redshift above 2, through the measurement of the forest absorptions auto-correlation and cross-correlations with quasars. Furthermore, it will provide...
I will briefly introduce cosmic inflation and dark energy and combine them in quintessential inflation. A stochastic spectrum of primordial gravitational waves (PGWs) is expected from inflation, but it is unobservable in the near future. I will discuss some ways to boost the inflation generated PGWs, in quintessential inflation and beyond, which may result in characteristic observable spectra....
The Vera C. Rubin Observatory, currently under construction on Cerro Pachón in Chile, will feature an 8.4-meter telescope, the largest digital camera in the world for astronomy (3200 megapixels), an automated data processing system, and an online public engagement platform. Rubin will conduct the Legacy Survey of Space and Time (LSST), and it will operate on an automated cadence, capturing an...
The principle of relativity is the requirement that the equations describing the laws of physics have the same form in all admissible frames of reference. To complete realisation of the principle required the recent refinement of Einstein's theories of gravity, since they did not distinguish the admissible reference frames (but confused reference frames with coordinate systems). The new...
The equivalence principle naturally provides gravity with a geometrical character. However, the precise geometry we employ to describe it admits a certain flexibility. In particular, within a metric-affine framework, Einstein’s gravity can be equivalently ascribed to the three independent objects that characterise a connection, i.e., curvature, torsion and non-metricity. After reviewing these...
Using conformal invariance of gravitational waves, we show that for a luminal modified gravity theory, the gravitational-wave propagation and luminosity distance are the same as in general relativity. The relation between the gravitational-wave and electromagnetic-wave luminosity distance gets however modified for electromagnetism minimally coupled to the Jordan frame metric. Using effective...
La física es un magnífico entramado de ideas que nos permite comprender mejor el universo que habitamos y dónde nos ubicamos en el mismo. A este fin, haremos un breve recorrido por los principales resultados de la física contemporánea, relacionándolos entre sí. El viaje nos llevará hasta las fronteras mismas del conocimiento… ¡y más allá!
No se usarán ecuaciones y no es necesario conocimiento...
In this talk, we will start by reviewing the geometrical entities that constitute the basis of metric-affine gravity: the metric and the connection, as well as the decomposition of the latter. Then the quadratic theory will be presented and we will show how strong the stability conditions for the four vector irreducible pieces of the torsion and the nonmetricity tensors are. These will reduce...
It’s long been recognized that higher-order theories generically propagate an excess of
degrees of freedom which, to make matters worse, are associated with negative (kinetic) energies. These are known as Ostrogradski instabilities. Until very recently, such instabilities were immediately disregarded as unphysical and methods were developed to construct theories that would avoid them. Indeed,...
Metric-Affine Gravity constitutes a natural extension of General Relativity that incorporates the notions of torsion and nonmetricity in an enriched space-time geometry. In particular, the spin angular momentum of matter turns out to operate as a source of torsion, whereas the so-called dilation and shear currents of matter act as sources of nonmetricity. In this talk, I will introduce the...
With Euclid and the Vera Rubin Observatory starting their observations in the coming years, we need highly precise and accurate data analysis techniques to optimally extract the information from weak lensing data. However, the standard approach based on fitting some summary statistics is inevitably suboptimal and imposes approximations on the statistical and physical modeling. I will present a...
A post-inflationary epoch with a stiff equation of state parameter, like it happens in quintessential inflation, leads to an interesting phenomenology in the presence of non-minimally coupled spectator fields with internal symmetries. I will discuss how this scenario can provide an efficient reheating mechanism, the formation of cosmic defects and the production of gravitational waves and...
Due to the unprecedented sensitivity and large field of views, extracting the maximum amount of information remains a key challenge in future surveys. In this talk, I will discuss the current challenges in analyzing the expected big data from upcoming large scale surveys, and present several promising techniques to perform high-dimensional likelihood-free inference and emulation using...
Running vacuum models and viscous dark matter scenarios beyond perfect fluid idealization are two appealing theoretical strategies that have been separately studied as alternatives to solve some problems rooted in the ΛCDM cosmological model. In this talk, I will explain the cosmological consequences of combining these two notions in a single cosmological setting, paying...
Within the framework of modified gravity, the quasi-static and sub-horizon approximations are widely used in analyses aiming to identify departures from the concordance model at late-times. In general, it is assumed that time derivatives are subdominant with respect to spatial derivatives given that the relevant physical modes are those well inside the Hubble radius. In practice, the...
I will present a detailed approach for building models of interacting dark energy that incorporate vector fields conformally and disformally coupled to dark matter, independent of the underlying gravity theory. This discussion will include a focus on establishing general conditions to prevent the presence of ghost instabilities within the theory. For concreteness, we will consider the standard...
In this work, we investigate the growth of cosmological perturbations within a cosmological scenario where the early universe is dominated by dark matter and gradually becomes anisotropic at later times due to the presence of a small shear tensor associated with dark energy. To describe this, we employ the Bianchi I metric, which characterizes a spacetime background that is homogeneous but...
The generalized SU(2) Proca theory is a vector-tensor modified gravity theory where the action is invariant under both diffeomorphisms and global internal transformations of the SU(2) group. This work constitutes the first approach to investigate the physical properties of the theory at astrophysical scales. We have found solutions that naturally generalize the particle-like solutions of the...
In this work, we studied some compact object solutions in the Generalized SU(2) Proca theory. This modified gravity model is a vector-tensor theory whose action is invariant under global transformations of the SU(2) group and includes second-order derivative self-interactions of the vector field beyond the massive Yang- Mills theory. First, we studied two Lagrangian pieces consisting of four...
The Newtonian theory of gravity can be reformulated in the language of differential geometry as a non- relativistic theory in curved spacetime, where the source of the curvature is associated with the standard Newtonian gravitational potential. This is known as the Newton-Cartan (NC) theory, and although at a dynamic level it is absolutely equivalent to the standard Newtonian theory, the...
In this work we reviewed parametrizations of Dark Energy (DE) models focusing on potential late-time physics effects that could alleviate the Hubble Tension. We present a preliminary evaluation of the DE models proposed by Pan et. al. 2019, which consist of phenomenological parametrizations of the DE equation of state, $w = P/\rho$, in terms of the current value, $w_{0}$. In addition, we...
