2k citations · 12k across the 281 of their papers we have counts for
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On dark sector scalar field theories driven by cosmological -fields
Alex E. Bernardini, Orfeu Bertolami
The interplay of Hoyle-Narlikar (HN) creation field cosmology and scalar field models for the dark sector, including the generalized Chaplygin Gas (GCG), is investigated . Though o…
Cosmological and lunar laser ranging constraints on evolving dark energy in a nonminimally coupled curvature-matter gravity model
Riccardo March, Miguel Barroso Varela, Orfeu Bertolami +3
We analyze a cosmological solution to the field equations of a modified gravity model where curvature and matter are nonminimally coupled. The current Universe's accelerated expans…
Accretion of Generalized Chaplygin Gas onto Cosmologically Coupled Black Holes
Luis F. Reis, Mario C. Baldiotti, Orfeu Bertolami
We study the accretion of cosmic dark fluids, responsible for driving the accelerated expansion of the universe, onto cosmologically coupled black holes. More specifically, we focu…
Inflationary dynamics of non-minimally coupled matter-curvature theories
Miguel Barroso Varela, Orfeu Bertolami, Andreas Mantziris
This study examines how inflationary dynamics are affected by theories with a non-minimal coupling between matter and curvature. Both positive and negative corrections to th…
Density perturbations in nonminimally coupled gravity: symptoms of Lagrangian density ambiguity
Miguel Barroso Varela, Orfeu Bertolami
The evolution of density perturbations is analysed in a modified theory of gravity with a nonminimal coupling between curvature and matter. We consider the broken degeneracy betwee…
Gravitational wave polarizations in nonminimally coupled gravity
Miguel Barroso Varela, Orfeu Bertolami
The properties of metric perturbations are determined in the context of an expanding Universe governed by a modified theory of gravity with a non-minimal coupling between curvature…
Hubble tension in a nonminimally coupled curvature-matter gravity model
Miguel Barroso Varela, Orfeu Bertolami
The presently open problem of the Hubble tension is shown to be removed in the context of a modified theory of gravity with a non-minimal coupling between curvature and matter. By…
The de Sitter swampland conjectures in the context of Chaplygin-inspired inflation
Orfeu Bertolami, Robertus Potting, Paulo M. Sá
In this work, we discuss the de Sitter swampland conjectures in the context of the generalized Chaplygin-inspired inflationary model. We demonstrate that these conjectures can be s…
Equivalence principle violation in nonminimally coupled gravity and constraints from Lunar Laser Ranging
Riccardo March, Orfeu Bertolami, Marco Muccino +1
We analyze the dynamics of the Sun-Earth-Moon system in the context of a particular class of theories of gravity where curvature and matter are nonminimally coupled (NMC). These th…
Seeding the vacuum with entropy: the Chaplygin-like vacuum hypothesis
Orfeu Bertolami
It is proposed that the vacuum admits two different phases as described by the Chaplygin equation of state or its generalised version: a phase where the energy density behaves as i…
Theories of gravity with nonminimal matter-curvature coupling and the de Sitter swampland conjectures
Orfeu Bertolami, Cláudio Gomes, Paulo M. Sá
We discuss, in the context of alternative theories of gravity with nonminimal coupling between matter and curvature, if inflationary solutions driven by a single scalar field can b…
Primordial magnetic fields in theories of gravity with non-minimal coupling between curvature and matter
Orfeu Bertolami, Maria Margarida Lima, Filipe C. Mena
The existence of magnetic fields in the universe is unmistakable. They are observed at all scales from stars to galaxy clusters. However, the origin of these fields remains enigmat…
Multi-field cold and warm inflation and the de Sitter swampland conjectures
Orfeu Bertolami, Paulo M. Sá
We discuss under which conditions multi-field cold and warm inflationary models with canonical kinetic energy terms are compatible with the swampland conjectures about the emergenc…
Cassini and extra force constraints to nonminimally coupled gravity with screening mechanism
Riccardo March, Orfeu Bertolami, Marco Muccino +2
We consider a nonminimally coupled curvature-matter gravity theory at the Solar System scale. Both a fifth force of Yukawa type and a further non-Newtonian extra force that arises…
Pressureless stationary solutions in a Newton-Yukawa gravity model
T. D. Ferreira, J. Novo, N. A. Silva +2
Non-minimally coupled curvature-matter gravity models are an interesting alternative to the Theory of General Relativity and to address the dark energy and dark matter cosmological…
Inflation, phase transitions and the cosmological constant
Orfeu Bertolami
Cosmological phase transitions are thought to have taken place at the early Universe imprinting their properties on the observable Universe. There is strong evidence that, through…
Stability Conditions for the Horndeski Scalar Field Gravity Model
Cláudio Gomes, Orfeu Bertolami
We constrain the viable models of Horndeski gravity, written in its equivalent Generalised Galileon version, by resorting to the Witten positive energy theorem. We find that the fr…
A note on the comments of arXiv:2003.10154 [gr-qc] to our paper Nonminimally Coupled Boltzmann Equation I: Foundations (arXiv:2002.08184 [gr-qc])
Orfeu Bertolami, Cláudio Gomes
In this note we comment on remarks about our recent effort to understand the specificities of the Boltzmann equation in the context of the alternative theories of gravity with non-…
An Ostrogradsky Instability Analysis of Non-minimally Coupled Weyl Connection Gravity Theories
Rodrigo Baptista, Orfeu Bertolami
We study the Hamiltonian formalism of the non-minimally coupled Weyl connection gravity (NMCWCG) in order to check whether Ostrogradsky instabilities are present. The Hamiltonian o…
Nonminimally Coupled Boltzmann Equation I: Foundations
Orfeu Bertolami, Cláudio Gomes
We derive the Boltzmann equation in the context of a gravity theory with non-minimal coupling between matter and curvature. We show that as the energy-momentum tensor is not conser…
Cosmological Solutions of the Non-minimally Coupled Weyl Connection Gravity Theories
Rodrigo Baptista, Orfeu Bertolami
We consider a non-minimally coupled curvature-matter gravity model (NMC) with a Weyl connection, a theory referred to as non-minimally coupled Weyl connection gravity (NMCWCG). The…
Using numerical methods from nonlocal optics to simulate the dynamics of N-body systems in alternative theories of gravity
Tiago D. Ferreira, Nuno A. Silva, O. Bertolami +2
The generalized Schrödinger-Newton system of equations with both local and nonlocal nonlinearities is widely used to describe light propagating in nonlinear media under the paraxia…
Constraining a nonminimally coupled curvature-matter gravity model with ocean experiments
Riccardo March, Orfeu Bertolami, Marco Muccino +2
We examine the constraints on the Yukawa regime from the non-minimally coupled curvature-matter gravity theory arising from deep underwater ocean experiments. We consider the geoph…
Nonminimally coupled curvature-matter gravity models and Solar System constraints
Riccardo March, Orfeu Bertolami, Jorge Páramos +1
We discuss constraints to some nonminimally (NMC) coupled curvature-matter models of gravity by means of Solar System experiments. First we discuss a NMC gravity model which consti…