169 citations · 426 across the 14 of their papers we have counts for
15 papers
A general criterion to compare metric and Palatini formulations with arbitrary non-minimal couplings: the case of Natural Inflation
Andres Felipe Suarez Reyes, Juan P. Beltrán Almeida
We study Natural Inflation with several types of non-minimal couplings to gravity in metric and Palatini formalisms, focusing on how the choice of gravitational formulation affects…
Multifield curved solid: Early dark energy and perturbation instabilities
Juan P. Beltrán Almeida, Alejandro Guarnizo, Thiago S. Pereira +1
We introduce a multifield dark energy model with a nonflat field-space metric, in which one field is dynamical while the others have constant spatial gradients. The model is predic…
Structure formation in an anisotropic universe: Eulerian perturbation theory
Juan P. Beltrán Almeida, Josué Motoa-Manzano, Jorge Noreña +2
We present an effective Eulerian description, in the non-relativistic regime, of the growth of cosmological perturbations around a homogeneous but anisotropic Bianchi I spacetime b…
Anisotropic Scalar Field Dark Energy with a Disformally Coupled Yang-Mills Field
L. Gabriel Gomez, Yeinzon Rodriguez, Juan P. Beltran Almeida
In the context of scalar-tensor theories, the inclusion of new degrees of freedom coupled non-minimally to the gravitational sector might produce some appealing effects on the cosm…
-form quintessence: exploring dark energy of forms coupled to a scalar field
Alejandro Guarnizo, Juan P. Beltrán Almeida, César A. Valenzuela-Toledo
We consider a model based on form kinetic Lagrangians in the context of dark energy. The Lagrangian of the model is built with kinetic terms of the field strength for each -…
On the 4D generalized Proca action for an Abelian vector field
Erwan Allys, Juan P. Beltran Almeida, Patrick Peter +1
We summarize previous results on the most general Proca theory in 4 dimensions containing only first-order derivatives in the vector field (second-order at most in the associated S…
Generalized Proca action for an Abelian vector field
Erwan Allys, Patrick Peter, Yeinzon Rodriguez
We revisit the most general theory for a massive vector field with derivative self-interactions, extending previous works on the subject to account for terms having trivial total d…
On the stability and causality of scalar-vector theories
Pierre Fleury, Juan P. Beltran Almeida, Cyril Pitrou +1
Various extensions of standard inflationary models have been proposed recently by adding vector fields. Because they are generally motivated by large-scale anomalies, and the possi…
Scale and shape dependent non-Gaussianity in the presence of inflationary vector fields
Juan P. Beltran Almeida, Yeinzon Rodriguez, Cesar A. Valenzuela-Toledo
We consider cosmological inflationary models in which vector fields play some role in the generation of the primordial curvature perturbation . Such models are interesting becau…
The Suyama-Yamaguchi consistency relation in the presence of vector fields
Juan P. Beltran Almeida, Yeinzon Rodriguez, Cesar A. Valenzuela-Toledo
We consider inflationary models in which vector fields are responsible for part or eventually all of the primordial curvature perturbation ζ. Such models are phenomenologically int…
Feynman-like Rules for Calculating n-Point Correlators of the Primordial Curvature Perturbation
Cesar A. Valenzuela-Toledo, Yeinzon Rodriguez, Juan P. Beltran Almeida
A diagrammatic approach to calculate n-point correlators of the primordial curvature perturbation ζwas developed a few years ago following the spirit of the Feynman rules in Quantu…
de Sitter relativity: a natural scenario for an evolving Lambda
J. P. Beltran Almeida, C. S. O. Mayor, J. G. Pereira
The dispersion relation of de Sitter special relativity is obtained in a simple and compact form, which is formally similar to the dispersion relation of ordinary special relativit…
Signatures of Primordial non-Gaussianities in the Matter Power-Spectrum and Bispectrum: the Time-RG Approach
Nicola Bartolo, J. P. Beltran Almeida, Sabino Matarrese +2
We apply the time-renormalization group approach to study the effect of primordial non-Gaussianities in the non-linear evolution of cosmological dark matter density perturbations.…
A Singular Conformal Spacetime
R. Aldrovandi, J. P. Beltran Almeida, J. G. Pereira
The infinite cosmological "constant" limit of the de Sitter solutions to Einstein's equation is studied. The corresponding spacetime is a singular, four-dimensional cone-space, tra…
Time-Varying Cosmological Term: Emergence and Fate of a FRW Universe
R. Aldrovandi, J. P. Beltran Almeida, J. G. Pereira
A time-varying cosmological "constant" Lambda is consistent with Einstein's equation, provided matter and/or radiation is created or destroyed to compensate for it. Supposing an em…