Showing papers in "International Journal of Geometric Methods in Modern Physics in 2019"
TL;DR: In this article, an n-dimensional generalized Robertson-Walker space-time with divergence-free conformal curvature tensor exhibits a perfect fluid stress energy tensor for any f(R) gravity model.
Abstract: We show that an n-dimensional generalized Robertson–Walker (GRW) space-time with divergence-free conformal curvature tensor exhibits a perfect fluid stress–energy tensor for any f(R) gravity model....
129 citations
TL;DR: The lecture notes for the course given at the "XXVII International Fall Workshop on Geometry and Physics" held in Seville (Spain) in September 2018 as mentioned in this paper, reviewed the geometric formulation of...
Abstract: These are the lecture notes for the course given at the “XXVII International Fall Workshop on Geometry and Physics” held in Seville (Spain) in September 2018. We review the geometric formulation of...
96 citations
TL;DR: The corpuscular theory of gravity as discussed by the authors provides a way to unify most of the experimental observations (from astrophysical to galactic and cosmological scales) in a single framework, solely based on gravity and baryonic matter.
Abstract: The aim of this thesis is to provide a general description of the corpuscular theory of gravity. After reviewing some of the major conceptual issues emerging from the semiclassical and field theoretic approaches to Einstein's gravity, we present a synthetic overview of two novel (and extremely intertwined) perspectives on quantum mechanical effects in gravity: the horizon quantum mechanics formalism and the classicalization scheme. After this preliminary discussion, we then proceed with implementing the latter to several different scenarios, namely self-gravitating systems, the early Universe, and galactic dynamics.
Concerning the first scenario, we start by describing the generation of the Newtonian potential as the result of a coherent state of toy (scalar) gravitons. After that we employ this result to study some features of the gravitational collapse and to argue that black holes can be thought of a self-sustained quantum states, at the critical point, made of a large number soft virtual gravitons. We then refine this simplified analysis by constructing an effective theory for the gravitational potential of a static spherical symmetric system up to the first post-Newtonian correction. Additionally, we employ the horizon quantum mechanics formalism to study the causal structure emerging from the corpuscular scenario. Finally, we present a short discussion of corpuscular black holes in lower dimensional spaces.
After laying down the basics of corpuscular black holes, we present a generalization of the aforementioned arguments to cosmology. Specifically, we first introduce a corpuscular interpretation of the de Sitter spacetime. Then we use it as the starting point for a corpuscular formulation of the inflationary scenario and to provide an alternative viewpoint on the dark components of the LambdaCDM model.
The key message of this work is that the corpuscular theory of gravity offers a way to unify most of the experimental observations (from astrophysical to galactic and cosmological scales) in a single framework, solely based on gravity and baryonic matter.
74 citations
TL;DR: In this paper, the emergence of Finsler geometry in physics is divided into three categories: dual description of diferent physical systems, dual description, and dual description (DDE).
Abstract: Finsler geometry naturally appears in the description of various physical systems. In this review, I divide the emergence of Finsler geometry in physics into three categories: dual description of d...
70 citations
TL;DR: In this paper, the evolution equations of the electric field and magnetic field vectors of the polarized light ray traveling in a coiled optical fiber in the ordinary space into the non-linear space were derived.
Abstract: In this paper, we relate the evolution equations of the electric field and magnetic field vectors of the polarized light ray traveling in a coiled optical fiber in the ordinary space into the nonli...
62 citations
TL;DR: In this article, the authors compare the gravitational collapse of homogeneous perfect fluid with various equations of state in the framework of General Relativity and in R2 gravity, and make their calculations using dimension.
Abstract: We compare the gravitational collapse of homogeneous perfect fluid with various equations of state in the framework of General Relativity and in R2 gravity. We make our calculations using dimension...
43 citations
TL;DR: In a n-dimensional Friedmann-Robertson-Walker metric, it was shown in this paper that any analytical theory of gravity f(R,&#x 1d4a2;), where R is the curvature scalar and 4a2 is the Gauss-Bonnet topological inva...
Abstract: In a n-dimensional Friedmann–Robertson–Walker metric, it is rigorously shown that any analytical theory of gravity f(R,𝒢), where R is the curvature scalar and 𝒢 is the Gauss–Bonnet topological inva...
42 citations
TL;DR: Schwinger's algebra of selective measurements has a natural interpretation in the formalism of groupoids as discussed by the authors and its kinematical foundations, as well as the structure of the algebra of observables of the...
Abstract: Schwinger’s algebra of selective measurements has a natural interpretation in the formalism of groupoids. Its kinematical foundations, as well as the structure of the algebra of observables of the ...
41 citations
TL;DR: In this article, the quantum correction effects on the deflection of light in the space-time geometry of a quantum improved Kerr black hole pierced by an infinitely long cosmic string are calculated.
Abstract: In this work, we calculate the quantum correction effects on the deflection of light in the space-time geometry of a quantum improved Kerr black hole pierced by an infinitely long cosmic string. Mo...
41 citations
TL;DR: In this article, the singular Lagrangian systems on the framework of contact geometry were discussed and a dissipative behavior in contrast with the symplectic scenario was developed. But the system was not considered in this paper.
Abstract: In this paper, we discuss the singular Lagrangian systems on the framework of contact geometry. These systems exhibit a dissipative behavior in contrast with the symplectic scenario. We develop a c...
41 citations
TL;DR: A new picture of Quantum Mechanics based on the theory of groupoids is presented in this article, which provides the mathematical background for Schwinger's algebra of selective measurements and helps to un...
Abstract: A new picture of Quantum Mechanics based on the theory of groupoids is presented. This picture provides the mathematical background for Schwinger’s algebra of selective measurements and helps to un...
TL;DR: Moreas et al. as mentioned in this paper proposed a transition from a decelerated to an accelerated phase of the universe expansion from the simplification phase, which is similar to the one described in this paper.
Abstract: In the present paper, the work of Moreas et al. [P. H. R. S. Moraes, G. Ribeiro and R. A. C. Correa, A transition from a decelerated to an accelerated phase of the universe expansion from the simpl...
TL;DR: The kinematical foundations of Schwinger's algebra of selective measurements were discussed in this paper, where the authors considered the groupoids of quantum mechanics and showed that they can be viewed as a special case of groupoids.
Abstract: The kinematical foundations of Schwinger’s algebra of selective measurements were discussed in [F. M. Ciaglia, A. Ibort and G. Marmo, Schwinger’s picture of quantum mechanics I: Groupoids, To appea...
TL;DR: In this article, a solution for the Klein-Gordon equation in the presence of a Cornell potential under the influence of noninertial effects in the cosmic string space-time was found.
Abstract: In this paper, we find solutions for the Klein–Gordon equation in the presence of a Cornell potential under the influence of noninertial effects in the cosmic string space-time. Then, we study Klein–Gordon oscillator in the cosmic string space-time. In addition, we show that the presence of a Cornell potential causes the forming bound states for the Klein–Gordon equation in this kind of background.
TL;DR: In this paper, the construction of nonstandard Lagrangians and Hamiltonian structures for Lienard equations satisfying Chiellini condition is presented and their connection to time-dependent Hamiltonian formalism is discussed.
Abstract: The construction of nonstandard Lagrangians and Hamiltonian structures for Lienard equations satisfying Chiellini condition is presented and their connection to time-dependent Hamiltonian formalism...
TL;DR: In this paper, the inextensible flows of tangent bimagnetic particles in space were studied and they were obtained by Lorentz equation and showed that the flows of electric field can be characterized by the Lagrangian equation.
Abstract: In this work, we study inextensible flows of tangent bimagnetic particles in space. Moreover, we obtain the inextensible flows of electric field by Lorentz equation. Finally, we obtain new results ...
TL;DR: In this paper, the authors studied a para-Sakian manifold whose metric g is an η-Ricci soliton (g,V ) and almost η Ricci solitons.
Abstract: In this paper, we study para-Sasakian manifold (M,g) whose metric g is an η-Ricci soliton (g,V ) and almost η-Ricci soliton. We prove that, if g is an η-Ricci soliton, then either M is Einstein and...
TL;DR: In this paper, the exact charged solutions in a cloud of strings through minimal geometric deformation technique in three-dimensional gravity were explored, and the results showed that the deformation of strings in the cloud can be reduced to a linear deformation.
Abstract: This paper is devoted to exploring exact charged solutions in a cloud of strings through minimal geometric deformation technique in three-dimensional gravity. For this purpose, we first evaluate th...
TL;DR: In this paper, the entering of a catheter adjusts the heat transfer process in the heart transfer studies, where the catheterization has an imperative rule in heat transfer investigations, which is frequently applied to analyze and deal with the heart studies.
Abstract: Catheterization has an imperative rule in heat transfer investigations, which are frequently applied to analyze and deal with the heart transfer studies. Here, the entering of a catheter adjusts th...
TL;DR: In this paper, a collection of motivating examples to consider bm-symplectic forms and folded-type symplectic structures is presented, and models in celestial mechanics are provided for every bm symmetric structure.
Abstract: In this paper we analyze in detail a collection of motivating examples to consider bm-
symplectic forms and folded-type symplectic structures. In particular, we provide models in
Celestial Mechanics for every bm-symplectic structure. At the end of the paper, we introduce
the odd-dimensional analogue to b-symplectic manifolds: b-contact manifolds.
TL;DR: A characterization of a sphere using a compact gradient almost Ricci soliton and the lower bound on the integral of Ricci curvature in the direction of potential field was given in this article.
Abstract: We find a characterization of a sphere using a compact gradient almost Ricci soliton and the lower bound on the integral of Ricci curvature in the direction of potential field. Also, we use Poisson...
TL;DR: An orthogonality space is a set of sets endowed with a symmetric, irreflexive binary relation as mentioned in this paper, and each anisotropic quadratic space gives rise to such a structure.
Abstract: An orthogonality space is a set endowed with a symmetric, irreflexive binary relation. By means of the usual orthogonality relation, each anisotropic quadratic space gives rise to such a structure....
TL;DR: In this paper, proper conformal vector fields of pp-wave space-times in the f(R) theory of gravity using algebraic and direct integration techniques were studied, and it was shown that the fields of the vector fields are proper.
Abstract: In this paper, we have studied proper conformal vector fields of pp-wave space-times in the f(R) theory of gravity using algebraic and direct integration techniques. From this study, we found that ...
TL;DR: In this article, proper conformal vector fields of spatially homogeneous rotating space-times in the f(R) theory of gravity were studied in detail and a total of six cases have been discussed in detail.
Abstract: In this paper, we present a study of proper conformal vector fields of spatially homogeneous rotating space-times in the f(R) theory of gravity. A total of six cases have been discussed in detail. ...
TL;DR: In this article, realistic models of neutron stars are considered for simple R + αR2 gravity and equivalent Brance-Dicke theory with dilaton field in Einsein frame.
Abstract: The realistic models of neutron stars are considered for simple R + αR2 gravity and equivalent Brance–Dicke theory with dilaton field in Einsein frame. For negative values of α we have no acceptabl...
TL;DR: It is shown that the Chern connection of a Finsler metric can be interpreted as the Levi-Civita connection and the anisotropic curvature tensor is introduced, which is a way of handling tensors that depends on the direction remaining always in the same class.
Abstract: We introduce the anisotropic tensor calculus, which is a way of handling tensors that depends on the direction remaining always in the same class. This means that the derivative of an anisotropic t...
TL;DR: In this paper, a 3D contact metric manifold such that Qφ = φQ which admits a Yamabe soliton (g,V ) with the flow vector field V pointwise collinear with the Reeb vector field ξ is considered.
Abstract: If M is a 3-dimensional contact metric manifold such that Qφ = φQ which admits a Yamabe soliton (g,V ) with the flow vector field V pointwise collinear with the Reeb vector field ξ, then we show th...
TL;DR: In this article, the existence of wormholes in viable f(R,T) gravity models was evaluated in terms of the trace of the stress energy tensor of the matter.
Abstract: This paper is aimed to evaluate the existence of wormholes in viable f(R,T) gravity models (where R is the scalar curvature and T is the trace of stress–energy tensor of matter). The exact solution...
TL;DR: In this article, the weak field limit for a gravitational Lagrangian density Lg = (R + a 0R2 + ∑ k=1pa kR□kR)−g, where higher-order derivative terms in the Ricci scalar R are taken into account.
Abstract: We derive the weak field limit for a gravitational Lagrangian density Lg = (R + a0R2 +∑ k=1pa kR□kR)−g, where higher-order derivative terms in the Ricci scalar R are taken into account. The interes...
TL;DR: In this article, the coordinate equations of killing magnetic curves in ℝ13 with the magnetic vector field V under the frame {γ,V,V ∧γ′(s)}.
Abstract: We define the coordinate equations of killing magnetic curves γ(s) in ℝ13 with the magnetic vector field V under the frame {γ′(s),V,V ∧γ′(s)}. In particular, this yields to describe the geometrical...