arXiv subjects

Raul Henriquez-Ortiz

Publications and source records attributed to Raul Henriquez-Ortiz.

3 recordsLinked to original sources

arXiv2026

A multi-axion model of inflation and dark matter

Models with extra dimensions include a tower of massive states that unavoidably contribute to cosmological dynamics. In particular, after compactification, a higher-dimensional axion gives rise to a set of states whose dynamics at early times exhibit the properties of inflation and, at late times, those of dynamical dark matter. Interestingly, natural choices of parameters imply that the inflationary trajectory in field space is approximately geodesic, meaning that inflation is effectively driven by a single inflaton corresponding to the heaviest state. In this scenario, all inflationary observables, including the emerging spectral distortions, are consistent with current observational constraints, and exact numerical solutions of the equations of motion show that reheating can consistently proceed down to temperatures of a few MeV. Furthermore, all states lighter than the inflaton only come to dominate the energy density of the Universe during the matter-dominated era, thus behaving as dark matter at late times. These states undergo a cascade of decays into radiation, while maintaining a sufficient dark-matter abundance to account for the observed relic density. The lightest dark-matter candidate remains stable on timescales far exceeding the age of the Universe, thereby satisfying even the most conservative observational constraints.

hep-ph↗

arXiv2024

Spectral distortions from promising single and multifield inflationary models

Forthcoming missions probing the absolute intensity of the CMB are expected to be able to measure spectral distortions, which are deviations from its blackbody distribution. As cosmic inflation can induce spectral distortions, these experiments offer a possibility to further test the various promising inflationary proposals, whose predictions need to be carefully determined. After numerically fitting all inflationary observables to match current observations, we compute the predicted spectral distortions of various promising single and multifield inflationary models. The predictions of single-field inflationary models display deviations between 0.5% and 20% with respect to the standard cosmological model in the observable window, where multi-natural and axion-monodromy inflation stand out in this respect. In the case of multifield inflation, we observe a richer structure of the power spectrum, which, in the case of so-called hybrid attractors, yields spectral distortions about 100 times more intense than the standard signal. These observations open up questions about the relation among our results and other cosmological observables that are also to be probed soon, such as the production of primordial black holes and gravitational waves.

astro-ph.CO↗

arXiv2022

Spectral Distortions from Axion Monodromy Inflation

With the advent of new missions to probe spectral distortions of the cosmic microwave background with unprecedented precision, the study of theoretical predictions of these signals becomes a promising avenue to test our description of the early Universe. Meanwhile, axion monodromy still offers a viable framework to describe cosmic inflation. In order to explore new constraints on inflationary models based on axion monodromy while aiming at falsifying this scenario, we compute the spectral distortions predicted by this model, revealing oscillatory features that are compatible with Planck data. Further, the predicted distortions are up to 10% larger than the signals obtained from the fiducial LCDM model and are observable in principle. However, contrasting with the predictions of the simplest power-law inflationary potentials challenges the falsifiability of axion monodromy as it would require to reduce at least 100 times the current forecast error of the PIXIE satellite, which shall be possible at some projected observational setups.

astro-ph.CO↗