74 citations · 624 across the 44 of their papers we have counts for
30 papers · 1 filter
Power-Law Inflation in n-Dimensional Fractional Scalar Field Cosmology: Observational Constraints and Dynamical Analysis
Daniel Oliveira, Seyed Rasouli, Joao Marto +1
Power-law inflation with is conceptually simple and predicts a scalar tilt compatible with CMB data, but in four-dimensional Einstein gravity it…
Tunnelling in Quantum Cosmology: WKB vs SWKB
Duarte Guimarães, João Marto, Paulo Vargas Moniz
This study analyses WKB and Supersymmetric WKB (SWKB) methods in a closed Friedmann-Robertson-Walker (FRW) minisuperspace model to determine whether they yield different results in…
Gravitational Foundations and Exact Solutions in -Dimensional Fractional Cosmology
S. M. M. Rasouli, J. Marto, D. A. V. Oliveira +1
Three theoretically plausible techniques to developing a fractional scalar field cosmological model are pointed in this paper; the time-dependent kernel weighted action being then…
Black-hole evaporation for cosmological observers
Thiago de L. Campos, C. Molina, J. A. S. Lima
This work investigates the evaporation of black holes immersed in a de Sitter environment, using the Vaidya-de Sitter spacetime. The role of cosmological observers is highlighted i…
Hawking radiation with pure states
K. Sravan Kumar, João Marto
Hawking's seminal work on black hole radiation highlights a critical issue in our understanding of quantum field theory in curved spacetime (QFTCS), specifically the problem of uni…
Revisiting quantum field theory in Rindler spacetime with superselection rules
K. Sravan Kumar, João Marto
Quantum field theory (QFT) in Rindler spacetime is a gateway to understanding unitarity and information loss paradoxes in curved spacetime. Rindler coordinates map Minkowski spacet…
Phase space noncommutativity, power-law inflation and quantum cosmology
S. M. M. Rasouli, João Marto
Considering an arbitrary dimensional FLRW universe in the framework of a generalized Sáez--Ballester (SB) theory, we establish a noncommutative (NC) cosmological model. We concentr…
Parity asymmetry of primordial scalar and tensor power spectra
K. Sravan Kumar, João Marto
Although the cosmic microwave background (CMB) is largely understood to be homogeneous and isotropic, the CMB angular power spectra present anomalies that seem to break down parity…
Hawking radiation and black hole gravitational back reaction - A quantum geometrodynamical simplified model
João Marto
The purpose of this paper is to analyse the back reaction problem, between Hawking radiation and the black hole, in a simplified model for the black hole evaporation in the quantum…
A varying Dark Energy effective speed of sound parameter in the phantom Universe
Imanol Albarran, Mariam Bouhmadi-López, João Marto
We analyse the phenomenological effects of a varying Dark Energy (DE) effective speed of sound parameter, , on the cosmological perturbations of three phantom…
Towards nonsingular rotating compact object in ghost-free infinite derivative gravity
Luca Buoninfante, Alan S. Cornell, Gerhard Harmsen +4
The vacuum solution of Einstein's theory of general relativity provides a rotating metric with a ring singularity, which is covered by the inner and outer horizons, and an ergo reg…
Conformally-flat, non-singular static metric in infinite derivative gravity
Luca Buoninfante, Alexey S. Koshelev, Gaetano Lambiase +2
In Einstein's theory of general relativity the vacuum solution yields a blackhole with a curvature singularity, where there exists a point-like source with a Dirac delta distributi…
Kinetic inflation in deformed phase space Brans-Dicke cosmology
S. M. M. Rasouli, J. Marto, P. V. Moniz
In this paper, by establishing a Brans-Dicke (BD) cosmology by means of a deformed phase space, in the absence of any scalar potential, cosmological constant and ordinary matter, w…
Inflationary Universe in Deformed Phase Space Scenario
S. M. M. Rasouli, N. Saba, M. Farhoudi +2
We consider a noncommutative (NC) inflationary model with a homogeneous scalar field minimally coupled to gravity. The particular NC inflationary setting produces entirely new cons…
Towards resolution of anisotropic cosmological singularity in infinite derivative gravity
Alexey S. Koshelev, João Marto, Anupam Mazumdar
In this paper, we will show that the equations of motion of the quadratic in curvature, ghost free, infinite derivative theory of gravity will not permit an anisotropic collapse of…
Schwarzschild -singularity is not permissible in ghost free quadratic curvature infinite derivative gravity
Alexey S. Koshelev, João Marto, Anupam Mazumdar
In this paper we will study the complete equations of motion for a ghost free quadratic curvature infinite derivative gravity. We will argue that within the scale of non-locality,…
Cosmic infinity: A dynamical system approach
Mariam Bouhmadi-López, João Marto, João Morais +1
Dynamical system techniques are extremely useful to study cosmology. It turns out that in most of the cases, we deal with finite isolated fixed points corresponding to a given cosm…
Interacting 3-form dark energy models: distinguishing interactions and avoiding the Little Sibling of the Big Rip
João Morais, Mariam Bouhmadi-López, K. Sravan Kumar +2
In this paper we consider 3-form dark energy (DE) models with interactions in the dark sector. We aim to distinguish the phenomenological interactions that are defined through the…
-essence model from the mechanical approach point of view: coupled scalar field and the late cosmic acceleration
Mariam Bouhmadi-López, K. Sravan Kumar, João Marto +2
In this paper, we consider the Universe at the late stage of its evolution and deep inside the cell of uniformity. At these scales, we can consider the Universe to be filled with d…
Classical and quantum cosmology of the little rip abrupt event
Imanol Albarran, Mariam Bouhmadi-López, Claus Kiefer +2
We analyze from a classical and quantum point of view the behavior of the universe close to a little rip, which can be interpreted as a big rip sent towards the infinite future. Li…
Gravitational waves in attractors
K. Sravan Kumar, João Marto, Paulo Vargas Moniz +1
We study inflation in the attractor model under a non-slow-roll dynamics with an ansatz proposed by Gong \& Sasaki \cite{Gong:2015ypa} of assuming . Under th…
Non-slow-roll dynamics in attractors
K. Sravan Kumar, João Marto, Paulo Vargas Moniz +1
In this paper we consider the attractor model and study inflation under a non-slow-roll dynamics. More precisely, we follow the approach recently proposed by Gong and Sasaki \c…
Inflation in a two 3-form fields scenario
K. Sravan Kumar, J. Marto, Nelson J. Nunes +1
A setting constituted by 3-form fields, without any direct interaction between them, minimally coupled to gravity, is introduced in this paper as a framework to study…
Improved dynamics and gravitational collapse of tachyon field coupled with a barotropic fluid
Joao Marto, Yaser Tavakoli, Paulo Vargas Moniz
We consider a spherically symmetric gravitational collapse of a tachyon field with an inverse square potential, which is coupled with a barotropic fluid. By employing an holonomy c…