arXiv subjects

Rubén Cordero

Publications and source records attributed to Rubén Cordero.

11 recordsLinked to original sources

arXiv2025

Lovelock type brane cosmology

The cosmological implications of the geodetic brane gravity model, enhanced by geometrical terms of Gibbons-Hawking-York (GHY) type and Gibbons-Hawking-York-Myers type (GHYM), carefully constructed as combinations of intrinsic and extrinsic curvatures, are examined. All the geometrical terms under study belong to a set named Lovelock-type brane models. The combined model gives rise to a second-order differential equation of motion. Under a Friedmann-Robertson-Walker (FRW) geometry defined on a $(3+1)$-dimensional world volume, together with a perfect fluid matter content, the emerging universe of this model evolves in a 5-dimensional Minkowski background, yielding peculiar facts. The resulting Friedmann-type equation is written in terms of energy density parameters, where fine-tuning is needed to probe interesting cosmological processes close to the current data. In this sense, Lovelock-type brane models might underlie the cosmic acceleration. Indeed, we find that these correction terms become significant at low energies/late times. The model exhibits self-accelerating (non-self-accelerating) behavior for the brane expansion, and in the case where the radiation-like contribution due to the existence of the extra dimension vanishes its behavior is the same as the Dvali-Gabadadze-Porrati (DGP) brane cosmology and its generalization to the Gauss-Bonnet (GB) brane gravity. Likewise, Einstein cosmology is recovered when the radiation-like contribution fades away along with the odd polynomials in brane extrinsic curvature.

gr-qc↗

arXiv2025

Neutrino Lorentz invariance violation from the CPT-even SME coefficients through a tensor interaction with cosmological scalar fields

Numerous non-standard interactions between neutrinos and scalar fields have been suggested in the literature. In this work, we have outlined the case of tensorial neutrino non-standard interactions with scalar fields, which can be related to the effective CPT-even dimension-4 operators of the Standard Model Extension (SME). Moreover, in this paper, we have mostly analyzed the projected sensitivities to the CPT-even isotropic $c_{αβ}$ and $Z-$spatial $c_{αβ}^{ZZ}$ SME coefficients, in the context of a long-baseline experimental configuration. We study the particular case of DUNE and show its sensitivity to this type of new physics. The current IceCube experiment and upcoming neutrino experiments such as KM3NeT, IceCube-Gen2, and GRAND proposals may clarify these classes of neutrino non-standard interactions.

hep-ph↗

arXiv2024

Neutrino Lorentz invariance violation and ultralight axion-like dark matter searches at the European Spallation Source

The dark matter conundrum stands out as one of the central challenges to understand in both particle physics and cosmology. The ultralight axion-like particle (UALP) is an appealing dark matter candidate that can be searched for in neutrino oscillation experiments. In this work, we examine the interaction among neutrinos and a UALP; such interaction might induce violations of the Lorentz and $CPT$ symmetries. We assess the sensitivity to both the isotropic $CPT-$odd Standard Model Extension (SME) coefficients $(a_L)^T$ and effective neutrino-UALP couplings $\tilde{g}$ at the next-to-next generation neutrino oscillation experiment at the European Spallation Source (ESS).

hep-ph↗

arXiv2024

Neutrino Lorentz Invariance Violation from Cosmic Fields

From a cosmological perspective, scalar fields are well-motivated dark matter and dark energy candidates. Several possibilities of neutrino couplings with a time-varying cosmic field have been investigated in the literature. In this work, we present a framework in which violations of Lorentz invariance (LIV) and $CPT$ symmetry in the neutrino sector could arise from an interaction among neutrinos with a time-varying scalar field. Furthermore, some cosmological and phenomenological aspects and constraints concerning this type of interaction are discussed. Potential violations of Lorentz and $CPT$ symmetries at present and future neutrino oscillation experiments such as IceCube and KM3NeT can probe this scenario.

hep-ph↗

arXiv2024

General perturbations in D+1 standard and brane cosmology revisited

In the present work, we generalize the theory of perturbations in a D + 1 dimensional space-time with cosmological constant, studying scalar, vector and tensor perturbations, as well as its structure in Newtonian and Synchronous gauge. We also show the theory of perturbations in the context of brane cosmology, where branes are embedded in a set of D-spatial dimensions, a temporal dimension, and an additional spatial dimension. In both, standard and brane cosmology an unperturbed spacetime is provided with a Friedmann-Lemaitre-Robertson-Walker metric and arbitrary sectional curvature, the matter content has the shape of a perfect fluid. In addition, we consider the arbitrary sectional curvature, obtaining the respective equations in the Newtonian and Synchronous gauge. We highlight that the results presented in this article can be used to treat brane cosmology with two concentric branes or tackle the σ_{8} tension with a braneworld approach. Finally, as an example of the utility of all the technology presented in this paper, we show an application to the energy ux and the repercussions in the framework of the brane-worlds.

gr-qc↗

arXiv2023

European Spallation Source as a searching tool for an ultralight scalar field

Dark matter (DM) nature is one of the major issues in physics. The search for a DM candidate has motivated the known proposal of an ultralight scalar field (ULSF). We explore the possibility to search for this ULSF at the upcoming European Spallation Source neutrino Super-Beam experiment. We have considered the recent study case in which there could be an interaction between the ULSF and active neutrinos. We have found that in this future experimental setup, the sensitivity is competitive with other neutrino physics experiments. We show the expected future sensitivity for the main parameter modeling the interaction between ULSF and neutrinos.

hep-ph↗

arXiv2020

Cosmological restrictions for two DGP branes in a bulk with compactified extra dimension

We investigate the cosmological consequences of a two brane system embedded in a higher dimensional background spacetime with a compactified extra dimension described with an action that include the intrinsic curvature for each brane. We find that the dynamics of each brane is related to the other by means of cosmological restrictions that involve the scale factors, the equation of state parameters and the Hubble parameters of the two branes. We analyze the evolution of the scale factor and the equation of state parameter for the hidden brane when in the visible brane is present a cosmological constant, radiation or non-relativistic matter. The topological restrictions give rise to the cosmological scenarios without initial singularity, recollapsing and oscillating universes.

hep-th↗

arXiv2015

A possible geometrical origin of the accelerated expansion of the universe

The modified geodetic brane cosmology (MGBC) is tested with observational data. The MGBC is derived from the geodetic brane gravity action corrected by the extrinsic curvature of the braneworld. The density parameter coming from this additional term produces an accelerated expansion of geometrical origin. Subject to the Supernovae Ia, Observable Hubble parameter, Baryon Acoustic Oscillations and Cosmic Microwave Background probes, the obtained fit provides enough evidence in the sense that the extrinsic curvature effect is able to reproduce the accelerated expansion of the universe without need of invoking dark energy, exotic matter or cosmological constant. Moreover the MGBC is free of the problems present in other braneworld models.

astro-ph.CO↗

arXiv2015

A possible cosmological application of some thermodynamic properties of the black body radiation in $n-$dimensional Euclidean spaces

In this work we present the generalization of some thermodynamic properties of the black body radiation (BBR) towards an $n-$dimensional Euclidean space. For this case the Planck function and the Stefan-Boltzmann law have already been given by Landsberg and de Vos and some adjustments by Menon and Agrawal. However, since then no much more has been done on this subject and we believe there are some relevant aspects yet to explore. In addition to the results previously found we calculate the thermodynamic potentials, the efficiency of the Carnot engine, the law for adiabatic processes and the heat capacity at constant volume. There is a region at which an interesting behavior of the thermodynamic potentials arise, maxima and minima appear for the $n-d$ BBR system at very high temperatures and low dimensionality, suggesting a possible application to cosmology. Finally we propose that an optimality criterion in a thermodynamic framework could have to do with the $3-d$ nature of the universe.

gr-qc↗

arXiv2014

Quantum modified Regge-Teitelboim cosmology

The canonical quantization of the modified geodetic brane cosmology which is implemented from the Regge-Teitelboim model and the trace of the extrinsic curvature of the brane trajectory, K, is developed. As a second-order derivative model, on the grounds of the Ostrogradski Hamiltonian method and the Dirac's scheme for constrained systems, we find suitable first- and second-class constraints which allow for a proper quantization. We also find that the first-class constraints obey a sort of truncated Virasoro algebra. The effective quantum potential emerging in our approach is exhaustively studied where it shows that an embryonic epoch is still present. The quantum nucleation is sketched where we observe that it is driven by an effective cosmological constant.

gr-qc↗

arXiv2012

Modified geodetic brane cosmology

We explore the cosmological implications provided by the geodetic brane gravity action corrected by an extrinsic curvature brane term, describing a codimension-1 brane embedded in a 5D fixed Minkowski spacetime. In the geodetic brane gravity action, we accommodate the correction term through a linear term in the extrinsic curvature swept out by the brane. We study the resulting geodetic-type equation of motion. Within a Friedmann-Robertson-Walker metric, we obtain a generalized Friedmann equation describing the associated cosmological evolution. We observe that, when the radiation-like energy contribution from the extra dimension is vanishing, this effective model leads to a self-(non-self)-accelerated expansion of the brane-like universe in dependence on the nature of the concomitant β-parameter associated with the correction, which resembles an analogous behaviour in the DGP brane cosmology. Several possibilities in the description for the cosmic evolution of this model are embodied and characterized by the involved density parameters related in turn to the cosmological constant, the geometry characterizing the model, the introduced β-parameter as well as the dark like-energy and the matter content on the brane.

gr-qc↗