74 citations · 632 across the 33 of their papers we have counts for
27 papers · 1 filter
Dynamical perturbations of black-hole punctures: effects of slicing conditions
Sean E. Li, Thomas W. Baumgarte, Kenneth A. Dennison +1
While numerous numerical relativity simulations adopt a 1+log slicing condition, shock-avoiding slicing conditions form a viable and sometimes advantageous alternative. Despite bot…
Bona-Massó slices of Reissner-Nordström spacetimes
Sean E. Li, Thomas W. Baumgarte, Kenneth A. Dennison +1
Motivated by recent numerical relativity simulations of charged black holes and their interactions, we explore the properties of common slicing conditions in Reissner-Nordström spa…
Quest for eternal oscillons
T. S. Mendonça, H. P. de Oliveira
Nonlinear field theories produce unstable but long-lived configurations known as oscillons. These structures have been studied with asymmetric and symmetric double-well potentials…
The Bondi problem revisited: a spectral domain decomposition code
M. A. Alcoforado, W. O. Barreto, H. P. de Oliveira
We present a simple domain decomposition code based on the Galerkin-Collocation method to integrate the field equations of the Bondi problem. The algorithm is stable, exhibits expo…
Multidomain Galerkin-Collocation method: characteristic spherical collapse of scalar fields
M. A. Alcoforado, W. O. Barreto, H. P. de Oliveira
We initiate a systematic implementation of the spectral domain decomposition technique with the Galerkin-Collocation (GC) method in situations of interest such as the spherical col…
Puncture black hole initial data: a single domain Galerkin-Collocation method for trumpet and wormhole data sets
P. C. M. Clemente, H. P. de Oliveira
We present a single domain Galerkin-Collocation method to calculate puncture initial data sets for single and binary, either in the trumpet or wormhole geometries. The combination…
A (gravitational) toy story
W. Barreto, H. P. de Oliveira, B. Rodriguez-Mueller
Frequently in Physics, insights and conclusions can be drawn from simple, idealized models. The discovery of critical behavior in the gravitational collapse of a massless scalar fi…
Nonlinear evolution of cylindrical gravitational waves: numerical method and physical aspects
Juliana Celestino, H. P. de Oliveira, E. L. Rodrigues
General cylindrical waves are the simplest axisymmetrical gravitational waves that contain both and modes of polarization. In this paper, we have studied the evolution…
Aspects of Wave Turbulence in Preheating
José A. Crespo, H. P. de Oliveira
In this work we have studied the nonlinear preheating dynamics of the inflationary model. It is well established that after a linear stage of preheating characte…
Numerical evolution of general Robinson-Trautman spacetimes: code tests, wave forms and the efficiency of the gravitational wave extraction
H. P. de Oliveira, E. L. Rodrigues, J. E. F. Skea
We present an efficient numerical code based on spectral methods to integrate the field equations of general Robinson-Trautmann spacetimes. The most natural basis functions for the…
The dynamics of apparent horizons in Robinson-Trautman spacetimes
H. P. de Oliveira, E. L. Rodrigues, I. Damião Soares
We present an alternative scheme of finding apparent horizons based on spectral methods applied to Robinson-Trautman spacetimes. We have considered distinct initial data such as re…
Numerical Evolution of axisymmetric vacuum spacetimes: a code based on the Galerkin method
H. P. de Oliveira, E. L. Rodrigues
We present the first numerical code based on the Galerkin and Collocation methods to integrate the field equations of the Bondi problem. The Galerkin method like all spectral metho…
The low dimensional dynamical system approach in General Relativity: an example
H. P. de Oliveira, E. L. Rodrigues, I. Damião Soares +1
In this paper we explore one of the most important features of the Galerkin method, which is to achieve high accuracy with a relatively modest computational effort, in the dynamics…
Homoclinic chaos in the dynamics of a general Bianchi IX model
H. P. de Oliveira, A. M. Ozorio de Almeida, I. Damião Soares +1
The dynamics of a general Bianchi IX model with three scale factors is examined. The matter content of the model is assumed to be comoving dust plus a positive cosmological constan…
Galerkin Method in the Gravitational Collapse: a Dynamical System Approach
H. P. de Oliveira, I. Damião Soares
We study the general dynamics of the spherically symmetric gravitational collapse of a massless scalar field. We apply the Galerkin projection method to transform a system of parti…
Density perturbations in warm inflation and COBE normalization
H. P. de Oliveira
Starting from a gauge invariant treatment of perturbations an analytical expression for the spectrum of long wavelength density perturbations in warm inflation is derived. The adia…
On Perturbations in Warm Inflation
H. P. De Oliveira, S. E. Jorás
Warm inflation is an interesting possibility of describing the early universe, whose basic feature is the absence, at least in principle, of a preheating or reheating phase. Here w…
Chaos and Universality in the Dynamics of Inflationary Cosmologies
H. P. de Oliveira, S. L. Sautu, I. Damião Soares +1
We describe a new statistical pattern in the chaotic dynamics of closed inflationary cosmologies, associated with the partition of the Hamiltonian rotational motion energy and hype…
Chaos and a Resonance Mechanism for Structure Formation in Inflationary Models
H. P. de Oliveira, I. Damiao Soares
We exhibit a resonance mechanism of amplification of density perturbations in inflationary mo-dels, using a minimal set of ingredients (an effective cosmological constant, a scalar…
Chaos in Preinflationary Friedmann-Robertson-Walker Universes
G. A. Monerat, H. P. de Oliveira, Ivano D. Soares
The dynamics of a preinflacionary phase of the universe, and its exit to inflation, is discussed. This phase is modeled by a closed Friedmann-Robertson-Walker geometry, the matter…
Chaotic exit to inflation: pre-inflationary Friedmann-Robertson-Walker universes
G. A. Monerat, H. P. de Oliveira, I. Damiao Soares
We show that homogeneous and isotropic cosmological models with radiation and scalar field have, in general, two possible chaotic exits to inflation. These models may describe the…
Dynamical System Analysis for Inflation with Dissipation
H. P. de Oliveira, Rudnei O. Ramos
We examine the solutions of the equations of motion for an expanding Universe, taking into account the radiation of the inflaton field energy. We then analyze the question of the g…
Chaos in Anisotropic Pre-Inflationary Universes
H. P. de Oliveira, I. Damiao Soares, T. J. Stuchi
We study the dynamics of anisotropic Bianchi type-IX models with matter and cosmological constant. The models can be thought as describing the role of anisotropy in the early stage…
Critical phenomena of collapsing massless scalar wave packets
Anzhong Wang, Henrique P. de Oliveira
An analytical model that represents the collapse of a massless scalar wave packet with continuous self-similarity is constructed, and critical phenomena are found. In the supercrit…