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Vicente A. Arévalo

Publications and source records attributed to Vicente A. Arévalo.

4 recordsLinked to original sources
arXiv2025

The DKP Equation in Presence of a Woods-Saxon Potential: Transmission Resonances and Bound States

In this article, we solve the Duffin-Kemmer-Petiau (DKP) equation in the presence of the Woods-Saxon potential barrier and well for spin-one particles. We derive the scattering solution in terms of the Gaussian hypergeometric function ${}_2F_1(a, b; c; z)$, the regularized Gaussian hypergeometric function ${}_2\tilde{F}_1(a, b; c; z)$, and the Gamma function $Γ(x)$. Our analysis reveals the presence of transmission resonances. To observe these resonances, we calculate and plot the transmission $T$ and reflection $R$ coefficients for various parameters of the Woods-Saxon potential barrier. Our results are compared with those obtained for the square potential barrier and the cusp potential barrier, which represent limiting cases of the Woods-Saxon potential barrier. Furthermore, we investigate the bound state solutions, determining the critical turning point $V_{cr}$ to study particle-antiparticle creation and compute the norm $N$. Finally, we also compare our results with those obtained for the square potential well and the cusp potential well, confirming that pair creation occurs in both potential wells.

quant-ph↗
arXiv2024

Observational predictions of some inflationary models

This paper presents the CMB angular power spectrum obtained using the \texttt{CAMB} code for three different models of inflation: the Starobinsky inflationary model, the generalized Starobinsky inflationary model, and the chaotic inflationary model with a step. The results are compared with the most recent data reported for the Planck mission. An analysis of the large ($\ell \lesssim 90$), intermediate ($90 \lesssim \ell \lesssim 900$), and small ($\ell \gtrsim 900 $) angular scales is performed. We report the position of the peaks in the intermediate region so as the cosmological parameters obtained in each of the models: age of the universe, $Ω_m$, $Ω_b$, $Ω_Λ$, $Ω_K$ and $n_\sca$. We also perform a Bayesian analysis using the \texttt{Cobaya} code to evaluate our three best-fitting models. Additionally, we generated contour plots $(n_\sca,r)$ for our inflationary models, taking into account the number of e-folds between the end of inflation and the completion of reheating.

gr-qc↗
arXiv2024

Time evolution of Von Neumann entropy for a Kerr-Taub-NUT black hole

In this work, we study the evolution of an evaporating black hole, described by the Kerr--Taub--NUT metric, which emits scalar particles. We found that allowing the black hole to radiate massless scalar particles increases the angular momentum loss rate while decreasing the loss rate of the NUT parameter and black hole mass. In fact, it means that angular momentum will disappear faster than the other black hole parameters (mass and NUT parameter) during the evaporation process. We also calculate the time evolution of the mass, angular momentum, and NUT parameter in order to get the evolution of the Von Neumann entropy of the black hole. We found that the entropy follows approximately the so-called Page curve, where the $β$ parameter, which quantifies the amount of radiation, affects the evaporation process. Implying that high $β$ values accelerate the evaporation process of a Kerr--Taub--NUT black hole.

gr-qc↗