Recent cosmological analyses combining Planck CMB data with baryon acoustic oscillation (BAO) measurements from the DESI collaboration have revealed a statistically significant preference for evolving dark energy (DE) models over the standard cosmological constant. In particular, fits using the Chevallier–Polarski–Linder (CPL) parameterization indicate a $\sim\!4\sigma$ deviation from a...
The statistical properties of the CMB anisotropies, reflecting the curvature inhomogeneities in the early Universe, are very well accounted for by assuming that they emerged from amplified vacuum fluctuations.
Being the result of a genuine quantum process, it is natural to wonder which properties of these primordial inhomogeneities are quantum, and which, if any, persisted until their...
Although the cosmic microwave background (CMB) is assumed to be only linearly polarized due to the Thomson scattering, some exotic theories predict the generation of circular polarization in the CMB during its propagation. E.g., Faraday conversion due to the supernovae remnants of first stars[1], the scattering by cosmic neutrino background[2], and Lorentz violation[3]. Thus, the circular...
Testing the limits of the inflationary paradigm can be achieved by moving beyond the standard slow-roll conditions. One approach is to constrain the dynamics of the inflaton field with a constant rate of roll, known as the constant-roll scenario, where the acceleration of the inflaton field satisfies $\ddot{\phi} \propto H \dot{\phi}$. This scenario has been studied extensively in the context...
The thermodynamics of black holes inspired the concept of black hole entropy, linking gravity and thermodynamics. When applied to cosmology, this leads to the standard Friedmann equations, which face challenges in explaining the universe’s evolution. Modified entropies have been proposed to resolve these issues. A recently introduced four-parameter generalized entropy unifies several known...
In this work we introduce a high-redshift cosmographic framework based on a new Padé expansion, providing improved accuracy at $z \gtrsim 1$. We estimate the cosmographic parameters $ H(z), \,q(z),\, j(z),\,s(z) $ at different fixed redhsift values by combining DESI BAO data (calibrated with Planck’s sound horizon scale $r_d$), the Pantheon Plus and DESy5 Type Ia supernova samples, and...
FURAX is a python framework created to utilize the functionality of JAX in modern cosmological
analysis with its ever increasing complexity and resource requirements. In particular, the ability
to run on GPU clusters, hardware acceleration, Just-In-Time compilation, and automatic differen-
tiation. This framework has already found its application in MEGATOP, a component-separation
pipeline...
The James Webb Space Telescope (JWST) has opened up new vistas to the very distant universe hitherto inaccessible. We make use of the UV Luminosity Functions deduced from JWST high-redshift observations to put constraints on the cross section of dark matter interacting with radiation. We find that though we only have little data from JWST as of now, the constraints are already competitive with...
I will discuss current and future observational probes which could bring new clues about the first moments of the Universe and the physics at the extreme energies, emphasizing their uniqueness and complementarity. The first part of the talk will cover the still-unexplored scientific potential of the cosmic microwave background polarized anisotropy observations. I will discuss the prospects...
The B-mode polarization of the cosmic microwave background (CMB) is a sensitive probe of primordial gravitational waves. A precise measurement of the tensor-to-scalar ratio $r$ enables stringent tests of inflation, yet the B-mode signal is hidden beneath Galactic foregrounds. Delta-map approximates the line-of-sight dependence of the foreground spectral energy distribution to first order,...
We investigate potential variations in fundamental constants—such as the fine-structure constant (α), the proton-to-electron mass ratio (μ), and Newton’s gravitational constant (G)—as a probe of physics beyond the Standard Model. Using high-resolution ultraviolet spectra of Fe V in the white dwarf G191-B2B from HST/STIS, combined with precise laboratory data, we constrain the time variation of...
Determining the absolute mass of neutrinos remains a major challenge in cosmology and particle physics. Recent DESI DR1/DR2 results suggest potential deviations from the standard ΛCDM model and indicate that conventional two-point statistics may be insufficient to robustly detect Mν – sparking controversial hints of a negative neutrino mass. To overcome these limitations, we introduce robust,...
Primordial black holes (PBH) have recently emerged as a very interesting candidate for the cold dark matter in the universe. We study their generation in a single field inflationary model with an inflection point potential and found that PBHs can be produced in our scenario in the asteroid-mass window with a nearly monochromatic mass fraction, accounting for the total dark matter in the...
