Results for "E. G. de Oliveira"

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Physical factorisation scheme for PDFs for non-inclusive applicationsOct 30 2013We introduce the physical factorisation scheme, which is necessary to describe observables which are `not completely inclusive'. We derive the formulae for NLO DGLAP evolution in this scheme, and also for the `rotation' of the conventional MSbar PDFs ... More
Improving the Drell-Yan probe of small x partons at the LHC via a k_t cutDec 13 2012Mar 07 2013We show that the observation of the Drell-Yan production of low-mass lepton-pairs (M < 20 GeV) at high rapidities (Y > 3) at the LHC can make a direct measurement of parton distribution functions (PDFs) in the low x region, x < 10^{-4}. We describe a ... More
The treatment of the infrared region in perturbative QCDJun 11 2012Sep 18 2012We discuss the contribution coming from the infrared region to NLO matrix elements and/or coefficient functions of hard QCD processes. Strictly speaking, this contribution is not known theoretically, since it is beyond perturbative QCD. For DGLAP evolution ... More
Scale dependence of open $c\bar{c}$ and $b\bar{b}$ production in the low $x$ regionOct 19 2016The `optimal' factorization scale $\mu_0$ is calculated for open heavy quark production. We find that the optimal value is $\mu_F=\mu_0\simeq 0.85\sqrt{p^2_T+m_Q^2} $; a choice which allows us to resum the double-logarithmic, $(\alpha_s\ln\mu^2_F\ln(1/x))^n$ ... More
An independent estimate of the triple-Pomeron couplingOct 07 2010Oct 11 2010The value of the important triple-Pomeron coupling is estimated by an unorthodox procedure using the known diffractive parton distribution functions. The result is g_{3P}\simeq 0.2g_N, where g_N is the Pomeron-nucleon coupling. This is in excellent agreement ... More
Drell-Yan as a probe of small x partons at the LHCMay 28 2012The predictions of Drell-Yan production of low-mass, lepton-pairs, at high rapidity at the LHC, are known to depend sensitively on the choice of factorization and renormalization scales. We show how this sensitivity can be greatly reduced by fixing the ... More
Treatment of the infrared contribution: NLO QED evolution as a pedagogic exampleMay 28 2013Oct 23 2013We show that the conventional prescription used for DGLAP parton evolution at NLO has an inconsistent treatment of the contribution from the infrared (IR) region. We illustrate the problem by studying the simple example of QED evolution, treating the ... More
Evolution in opening angle combining DGLAP and BFKL logarithmsApr 30 2014Oct 06 2014We present an evolution equation which simultaneously sums the leading BFKL and DGLAP logarithms for the integrated gluon distribution in terms of a single variable, namely the emission angle of the gluon. This form of evolution is appropriate for Monte ... More
BFKL equation for an integrated gluon densityJun 11 2014Aug 10 2014We show how it is possible to rewrite the BFKL equation for the unintegrated gluon distribution, in terms of integrated gluons, similar to that used in DGLAP. We add to our equation the next-to-leading log terms which provide exact energy-momentum conservation ... More
The small x gluon and b\bar{b} production at the LHCJun 27 2011We study open b\bar{b} production at large rapidity at the LHC in an attempt to pin down the gluon distribution at very low x. For the LHC energy of 7 TeV, at next-to-leading order (NLO), there is a large factorization scale uncertainty. We show that ... More
The LHC can probe small x PDFs; the treatment of the infrared regionNov 14 2012First, we show how to reduce the sensitivity of the NLO predictions of the Drell-Yan production of low-mass, lepton-pairs, at high rapidity, to the choice of factorization scale. In this way, observations of this process at the LHC can make direct measurements ... More
Noncommutativity in the early UniverseJan 07 2014May 04 2016In the present work, we study the noncommutative version of a quantum cosmology model. The model has a Friedmann-Robertson-Walker geometry, the matter content is a radiative perfect fluid and the spatial sections have zero constant curvature. In this ... More
Studying low-$x$ structure function models from astrophysical tau neutrinos events: double bang, lollipop and sugardaddy topologiesMar 13 2019Despite not have been yet identified by the IceCube detector, events generated from $\nu_{\tau}$ deep inelastic neutrino scattering in ice with varied topologies, such as double cascades (often called \textit{double bangs}), \textit{lollipops} and \textit{sugardaddies}, ... More
A comparative study for the pair-creation contact process using series expansionsMay 03 2007A comparative study between two distinct perturbative series expansions for the pair-creation contact process is presented. In contrast to the ordinary contact process, whose supercritical series expansions provide accurate estimates for its critical ... More
Hilfer-Katugampola fractional derivativeMay 15 2017Nov 10 2017We propose a new fractional derivative, the Hilfer-Katugampola fractional derivative. Motivated by the Hilfer derivative this formulation interpolates the well-known fractional derivatives of Hilfer, Hilfer-Hadamard, Riemann-Liouville, Hadamard, Caputo, ... More
DIS and the effects of fluctuations: a momentum space analysisJul 09 2008Among the dipole models of deep inelastic scattering at small values of the Bjorken variable $x$, one has been recently proposed which relates the virtual photon-proton cross section to the dipole-proton forward scattering amplitude in momentum space. ... More
Measurements of electrons from heavy-flavour hadron decays in pp, p-Pb and Pb-Pb collisions with ALICE at the LHCApr 15 2014Apr 16 2014Heavy-flavour hadrons, i. e. hadrons carrying charm or beauty quarks, are a well-suited probe to study the Quark-Gluon Plasma (QGP) in relativistic heavy-ion collisions. For this reason, measurements of electrons from heavy-flavour hadron decays have ... More
Measurements of the correlation between electrons from heavy-flavour hadron decays and light hadrons with ALICE at the LHCApr 16 2014In relativistic heavy-ion physics two-particle correlations provide a very useful tool to investigate the Quark-Gluon Plasma (QGP). This observable is sensitive to several of the properties of the QGP such as resonances, interaction of partons with the ... More
Can noncommutativity affect the whole history of the Universe?Sep 16 2011Feb 11 2016We study a classical, noncommutative (NC), Friedmann-Robertson-Walker cosmological model. The spatial sections may have positive, negative or zero constant curvatures. The matter content is a generic perfect fluid. The initial noncommutativity between ... More
Discovery of a cluster of galaxies behind the Milky Way: X-ray and optical observationsJun 15 2006Aug 18 2006We report the discovery of Cl 2334+48, a rich cluster of galaxies in the Zone of Avoidance, identified in public images from the XMM-Newton archive. We present the main properties of this cluster using the XMM-Newton X-ray data, along with new optical ... More
Running coupling and pomeron loop effects on inclusive and diffractive DIS cross sectionsSep 24 2012Within the framework of a (1+1)--dimensional model which mimics high energy QCD, we study the behavior of the cross sections for inclusive and diffractive deep inelastic $\gamma^*h$ scattering cross sections. We analyze the cases of both fixed and running ... More
Treatment of heavy quarks in QCDJul 12 2013Oct 09 2013We show that to correctly describe the effects of the heavy-quark mass, m_h, in DGLAP evolution, it is necessary to work in the so-called `physical' scheme. In this way, we automatically obtain a smooth transition through the heavy-quark thresholds. Moreover, ... More
Wide-Field CCD Photometry of the Globular Cluster M30Oct 16 1998Oct 17 1998We present new VI photometry for the halo globular cluster M30 (NGC 7099), and compute luminosity functions (LFs) in both bands for samples of about 15,000 hydrogen-burning stars from near the tip of the red giant branch (RGB) to over four magnitudes ... More
Inclusive hadron and photon production at LHC in dipole momentum spaceDec 21 2012Mar 28 2013Using a momentum space model for the dipole scattering amplitude we present an analysis of the saturation effects at LHC energies, describing the data on proton-proton and proton-lead collisions. The model is based on the asymptotic solutions of the Balitsky-Kovchegov ... More
Unintegrated parton distributions in nucleiJul 10 2013We study how unintegrated parton distributions in nuclei can be calculated from the corresponding integrated partons using the EPS09 parametrization. The role of nuclear effects is presented in terms of the ratio $R^A=\text{uPDF}^A/A\cdot \text{PDF}^N$ ... More
Quantized conductance in SnO2 nanobelts with rectangular hard-wallsJan 17 2012Mar 07 2013Quantized conductance is reported in high-crystalline tin oxide (SnO2) nanobelt back-gate field-effect transistors, at low temperatures. The quantized conductance was observed as current oscillations in the drain current vs. gate voltage characteristics, ... More
Momentum space saturation model for deep inelastic scattering and single inclusive hadron productionMar 10 2011We show how the AGBS model, originally developed for deep inelastic scattering applied to HERA data on the proton structure function, can also describe the RHIC data on single inclusive hadron yield for $d+Au$ and $p+p$ collisions through a new simultaneous ... More
Generic finite size scaling for discontinuous nonequilibrium phase transitions into absorbing statesOct 29 2015Based on quasi-stationary distribution ideas, a general finite size scaling theory is proposed for discontinuous nonequilibrium phase transitions into absorbing states. Analogously to the equilibrium case, we show that quantities such as, response functions, ... More
Finite-size scaling for discontinuous nonequilibrium phase transitionsApr 02 2018A finite size scaling theory, originally developed only for transitions to absorbing states [Phys. Rev. E {\bf 92}, 062126 (2015)], is extended to distinct sorts of discontinuous nonequilibrium phase transitions. Expressions for quantities such as, response ... More
Photoluminescence and High Temperature Persistent Photoconductivity Experiments in SnO2 NanobeltsDec 11 2012The Persistent Photoconductivity (PPC) effect was studied in individual tin oxide (SnO2) nanobelts as a function of temperature, in air, helium, and vacuum atmospheres, and low temperature Photoluminescence measurements were carried out to study the optical ... More
3D Hopping Conduction in SnO2 nanobeltsApr 11 2012Dec 11 2012The temperature dependence of the electrical transport of a individual tin oxide nanobelt was measured, in darkness, from 400 to 5K. We found four intrinsic electrical transport mechanisms through the nanobelt. It starts with Thermal-Activation Conduction ... More
Stability of fractional functional differential equationsJul 16 2018In this paper, we present a study on the Ulam-Hyers and Ulam-Hyers-Rassias stabilities of the solution of the fractional functional differential equation using the Banach fixed point theorem.
Nuclear shadowing in deep inelastic scattering on nuclei: a closer lookSep 14 2012The measurement of the nuclear structure function $F_2^A (x,Q^2)$ at the future electron-ion collider (EIC) will be of great relevance to understand the origin of the nuclear shadowing and to probe gluon saturation effects. Currently there are several ... More
Compact Groups of Galaxies selected by stellar mass: The 2MASS Compact Group CatalogueJul 09 2012We present a photometric catalogue of compact groups of galaxies (p2MCGs) automatically extracted from the 2MASS extended source catalogue. A total of 262 p2MCGs are identified, following the criteria of Hickson (1982), of which 230 survive visual inspection. ... More
Stochastic analysis of a miRNA-protein toggle switchJun 22 2011Within systems biology there is an increasing interest in the stochastic behavior of genetic and biochemical reaction networks. An appropriate stochastic description is provided by the chemical master equation, which represents a continuous time Markov ... More
The Average Kinetic Energy of the Superconducting StateJan 08 2002Isothermal magnetization curves are plotted as the magnetization times the magnetic induction, $4 \pi M \cdot B$, versus the applied field, H. We show here that this new curve is the average kinetic energy of the superconducting state versus the applied ... More
Spectroscopy of brown dwarf candidates in IC 348 and the determination of its substellar IMF down to planetary massesNov 16 2012Context. Brown dwarfs represent a sizable fraction of the stellar content of our Galaxy and populate the transition between the stellar and planetary mass regime. There is however no agreement on the processes responsible for their formation. Aims. We ... More
Heavy quarkonium production in a strong magnetic fieldMay 14 2013It is well known that in noncentral heavy-ion collisions a transient strong magnetic field is generated in the direction perpendicular to the reaction plane. The maximal strength of this field is estimated to be $eB \sim m^2_{\pi} \sim 0.02 \text{GeV}^2$ ... More
Numerical Evolution of axisymmetric vacuum spacetimes: a code based on the Galerkin methodSep 17 2008Nov 10 2011We 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 methods provide high accuracy with moderate computational effort. Several numerical ... More
A Fingerprint-based Access Control using Principal Component Analysis and Edge DetectionFeb 06 2015This paper presents a novel approach for deciding on the appropriateness or not of an acquired fingerprint image into a given database. The process begins with the assembly of a training base in an image space constructed by combining Principal Component ... More
Robustness of first-order phase transitions in one-dimensional long-range contact processesJun 13 2013It has been proposed (Phys. Rev. E {\bf 71}, 026121 (2005)) that unlike the short range contact process, a long-range counterpart may lead to the existence a discontinuous phase transition in one dimension. Aiming at exploring such link, here we investigate ... More
Discrete teleportation protocol of continuum spectra field statesApr 11 2002A discrete protocol for teleportation of superpositions of coherent states of optical cavity fields is presented. Displacement and parity operators are unconventionally used in Bell-like measurement for field states.
Results on the Aharonov-Bohm effect without contact with the solenoidNov 17 2017We add a confining potential to the Aharonov-Bohm model resulting in no contact of the particle with the solenoid (border); this is characterized by a unique self-adjoint extension of the initial Hamiltonian operator. It is shown that the spectrum of ... More
Explorando Sistemas Hamiltonianos II: A Natureza de Pontos de Equilibrio DegeneradosOct 25 2007Neste segundo artigo sobre sistemas Hamiltonianos, apresentamos o metodo da explosao para a determinacao da natureza de pontos fixos (pontos de equilibrio degenerados. Aplicamos o metodo a dois modelos hamiltonianos com um e dois graus de liberdade, respectivamente. ... More
Conformal Klein-Gordon equations and quasinormal modesMar 20 2006Using conformal coordinates associated with conformal relativity -- associated with de Sitter spacetime homeomorphic projection into Minkowski spacetime -- we obtain a conformal Klein-Gordon partial differential equation, which is intimately related to ... More
Multiresolution Division Multiplex (MRDM): A New Wavelet-based Multiplex SystemFeb 12 2015An original multiplex scheme is introduced, which is based on Mallat's multiresolution formulation of wavelet systems. This system is adaptable and its implementation is well matched to digital signal processors and computers. The approach termed multiresolution ... More
On Perturbations in Warm InflationMar 24 2001Jun 06 2001Warm 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 we analyze the dynamics of warm inflation generalizing the usual slow-roll ... More
Creation-annihilation processes in the ensemble of constant particle numberSep 19 2008We study, in the ensemble of constant particle number, processes in which a cluster of particles is annihilated and particles are created catalytically in active sites. In this ensemble, particles belonging to a cluster of $\ell$ particles jump to $\ell$ ... More
Contact process with long-range interactions: a study in the ensemble of constant particle numberSep 12 2008We analyze the properties of the contact process with long-range interactions by the use of a kinetic ensemble in which the total number of particles is strictly conserved. In this ensemble, both annihilation and creation processes are replaced by an ... More
AdS Geometry, projective embedded coordinates and associated isometry groupsSep 17 2003Mar 20 2006This work is intended to investigate the geometry of anti-de Sitter spacetime (AdS), from the point of view of the Laplacian Comparison Theorem (LCT), and to give another description of the hyperbolical embedding standard formalism of the de Sitter and ... More
Three dimensional distorted black holes: using the Galerkin-Collocation methodFeb 20 2015We present an implementation of the Galerkin-Collocation method to determine the initial data for non-rotating distorted three dimensional black holes in the inversion and puncture schemes. The numerical method combines the key features of the Galerkin ... More
Numerical evolution of radiative Robinson-Trautman spacetimesMar 31 2008The evolution of spheroids of matter emitting gravitational waves and null radiation field is studied in the realm of radiative Robinson-Trautman spacetimes. The null radiation field is expected in realistic gravitational collapse, and can be either an ... More
Temporal disorder does not forbid discontinuous absorbing phase transitions in low dimensional systemsMar 29 2016Jul 25 2016Distinct works have claimed that spatial (quenched) disorder can suppress the discontinuous absorbing phase transitions. Conversely, the scenario for temporal disorder for discontinuous absorbing phase transitions is unknown. In order to shed some light ... More
Subcritical series expansions for multiple-creation nonequilibrium modelsMar 27 2006Perturbative subcritical series expansions for the steady properties of a class of one-dimensional nonequilibrium models characterized by multiple-reaction rules are presented here. We developed long series expansions for three nonequilibrium models: ... More
On Conformal d'Alembert-Like EquationsFeb 02 2005Using conformal coordinates associated with projective conformal relativity we obtain a conformal Klein-Gordon partial differential equation. As a particular case we present and discuss a conformal `radial' d'Alembert-like equation. As a by-product we ... More
Temporal disorder does not forbid discontinuous absorbing phase transitions in low dimensional systemsMar 29 2016Nov 23 2016Distinct works have claimed that spatial (quenched) disorder can suppress the discontinuous absorbing phase transitions. Conversely, the scenario for temporal disorder for discontinuous absorbing phase transitions is unknown. In order to shed some light ... More
Phase transition in conservative diffusive contact processesSep 12 2008We determine the phase diagrams of conservative diffusive contact processes by means of numerical simulations. These models are versions of the ordinary diffusive single-creation, pair-creation and triplet-creation contact processes in which the particle ... More
Coherence and incoherence in extended broad band triplet interactionJan 31 2008In the present analysis we study the transition from coherent to incoherent dynamics in a nonlinear triplet of broad band combs of waves. Expanding the analysis of previous works, this paper investigates what happens when the band of available modes is ... More
Synchronization of Two and Three Optoeletronic Oscillators Operating in Chaotic Regime: Numerical Simulations and Schemes for Secure CommunicationOct 08 2016In this work we show a strategy for synchronization of three optoelectronic oscillators (OEO) operating in chaotic regime. Two applications of synchronized OEOs in secure communications are considered. In the first one the OEO is used to produce a pseudo-random ... More
Susceptibility of a two-level atom near an isotropic photonic band edge: transparency and band edge profile reconstructionMar 14 2015We discuss the necessary conditions for a two-level system in the presence of an isotropic band edge to be transparent to a probe laser field. The two-level atom is transparent whenever it is coupled to a reservoir constituted of two parts - a flat and ... More
Continuous Measurement of Atom-Number Moments of a Bose-Einstein Condensate by PhotodetectionJul 10 2003Jul 20 2004We propose a measurement scheme that allows determination of even-moments of a Bose-Einstein condensate (BEC) atom number, in a ring cavity, by continuous photodetection of an off-resonant quantized optical field. A fast cavity photocounting process limits ... More
A Near-Quadratic Lower Bound for the Size of Quantum Circuits of Constant TreewidthSep 30 2016We show that any quantum circuit of treewidth $t$, built from $r$-qubit gates, requires at least $\Omega(\frac{n^{2}}{2^{O(r\cdot t)}\cdot \log^4 n})$ gates to compute the element distinctness function. Our result generalizes a near-quadratic lower bound ... More
On the Satisfiability of Quantum Circuits of Small TreewidthApr 22 2014Feb 07 2016It has been known for almost three decades that many $\mathrm{NP}$-hard optimization problems can be solved in polynomial time when restricted to structures of constant treewidth. In this work we provide the first extension of such results to the quantum ... More
Canonizable Partial Order Generators and Regular Slice LanguagesSep 27 2010Jun 26 2012In a previous work we introduced slice graphs as a way to specify both infinite languages of directed acyclic graphs (DAGs) and infinite languages of partial orders. Therein we focused on the study of Hasse diagram generators, i.e., slice graphs that ... More
Characterization of the second- and third-order nonlinear optical susceptibilities of monolayer MoS$_2$ using multiphoton microscopyJun 26 2016Nov 15 2016We report second- and third-harmonic generation in monolayer MoS$_\mathrm{2}$ as a tool for imaging and accurately characterizing the material's nonlinear optical properties under 1560 nm excitation. Using a surface nonlinear optics treatment, we derive ... More
An Algorithmic Metatheorem for Directed TreewidthOct 02 2014Oct 08 2015The notion of directed treewidth was introduced by Johnson, Robertson, Seymour and Thomas [Journal of Combinatorial Theory, Series B, Vol 82, 2001] as a first step towards an algorithmic metatheory for digraphs. They showed that some NP-complete properties ... More
Characterization of the second- and third-order nonlinear optical susceptibilities of monolayer MoS$_2$ using multiphoton microscopyJun 26 2016We report second- and third-harmonic generation in monolayer MoS$_2$ as a tool for imaging and accurately characterizing the material's nonlinear optical properties under 1560 nm excitation. Using a surface nonlinear optics treatment, we derive expressions ... More
Propositional equality, identity types, and direct computational pathsJul 10 2011Aug 05 2013In proof theory the notion of canonical proof is rather basic, and it is usually taken for granted that a canonical proof of a sentence must be unique up to certain minor syntactical details (such as, e.g., change of bound variables). When setting up ... More
Automated Verification, Synthesis and Correction of Concurrent Systems via MSO LogicFeb 11 2014In this work we provide algorithmic solutions to five fundamental problems concerning the verification, synthesis and correction of concurrent systems that can be modeled by bounded p/t-nets. We express concurrency via partial orders and assume that behavioral ... More
Subgraphs Satisfying MSO Properties on z-Topologically Orderable DigraphsMar 18 2013Jun 17 2013We introduce the notion of z-topological orderings for digraphs. We prove that given a digraph G on n vertices admitting a z-topological order- ing, together with such an ordering, one may count the number of subgraphs of G that at the same time satisfy ... More
Embezzlement States are Universal for Non-Local StrategiesSep 03 2010We prove that the family of embezzlement states defined by van Dam and Hayden [vanDamHayden2002] is universal for both quantum and classical entangled two-prover non-local games with an arbitrary number of rounds. More precisely, we show that for each ... More
High Resolution Parameter Space from a Two Level Model on Semi-Insulating GaAsSep 25 2014Semi-insulating Gallium Arsenide (SI-GaAs) samples experimentally show, under high electric fields and even at room temperature, negative differential conductivity in N-shaped form (NNDC). Since the most consolidated model for n-GaAs, namely, "the model", ... More
Nonrelativistic Quantum Analysis of the Charged Particle-Dyon System on a Conical SpacetimeDec 17 2004Feb 17 2005In this paper we develop the nonrelativistic quantum analysis of the charged particle-dyon system in the spacetime produced by an idealized cosmic string. In order to do that, we assume that the dyon is superposed to the cosmic string. Considering this ... More
Compactly Supported One-cyclic Wavelets Derived from Beta DistributionsFeb 07 2015New continuous wavelets of compact support are introduced, which are related to the beta distribution. They can be built from probability distributions using 'blur'derivatives. These new wavelets have just one cycle, so they are termed unicycle wavelets. ... More
Nonrelativistic Scattering Analysis of Charged Particle by a Magnetic Monopole in the Global Monopole BackgroundJan 14 2003We analyze the nonrelativistic quantum scattering problem of a charged particle by an Abelian magnetic monopole in the background of a global monopole. In addition to the magnetic and geometric effects, we consider the influence of the electrostatic self-interaction ... More
Kaluza-Klein Magnetic Monopole in Five-Dimensional Global Monopole SapcetimeSep 18 2003Dec 15 2003In this paper we present a solution for Kaluza-Klein magnetic monopole in a five-dimensional global monopole spacetime. This new solution is a generalization of previous ones obtained by D. Gross and M. Perry (Nucl. Phys. B {\bf 226}, 29 (1983)) containing ... More
Graphene Based Waveguide Polarizers: In-Depth Physical Analysis and Relevant ParametersMay 27 2015Oct 07 2015Optical polarizing devices exploiting graphene embedded in waveguides have been demonstrated in the literature recently and both the TE- and TM-pass behaviors were reported. The determination of the passing polarization is usually attributed to graphene's ... More
Exact Solutions of the Klein-Gordon Equation in the Presence of a Dyon, Magnetic Flux and Scalar Potential in the Specetime of Gravitational DefectsMar 06 2006Jul 12 2006In this paper we analyse the relativistic quantum motion of a charged spin-0 particle in the presence of a dyon, Aharonov-Bohm magnetic field and scalar potential, in the spacetimes produced by an idealized cosmic string and global monopole. In order ... More
Stationary Coverage of a Stochastic Adsorption-Desorption Process with Diffusional RelaxationMar 02 1999May 22 2011We show that it is possible to derive the stationary coverage of an adsorption-desorption process of dimers with diffusional relaxation with a very simple ansatz for the stationary distribution of the process supplemented by a hypothesis of global balance. ... More
Comparison of solar radio and EUV synoptic limb charts during the present solar maximumJun 10 2016The present solar cycle is particular in many aspects: it had a delayed rising phase, it is the weakest of the last 100 years, and it presents two peaks separated by more than one year. To understand the impact of these characteristics on the solar chromosphere ... More
Dynamical gap generation in graphene nanoribbons: An effective relativistic field theoretical modelDec 07 2010Apr 22 2011We show that the assumption of a nontrivial zero band gap for a graphene sheet within an effective relativistic field theoretical model description of interacting Dirac electrons on the surface of graphene describes the experimental band gap of graphene ... More
Symmetry breaking effects upon bipartite and multipartite entanglement in the XY modelSep 07 2007Mar 18 2008We analyze the bipartite and multipartite entanglement for the ground state of the one-dimensional XY model in a transverse magnetic field in the thermodynamical limit. We explicitly take into account the spontaneous symmetry breaking in order to explore ... More
FINITE SIZE SCALING FOR FIRST ORDER TRANSITIONS: POTTS MODELMar 17 1995The finite-size scaling algorithm based on bulk and surface renormalization of de Oliveira (1992) is tested on q-state Potts models in dimensions D = 2 and 3. Our Monte Carlo data clearly distinguish between first- and second-order phase transitions. ... More
The AdS/CFT relation, quasi-normal modes and applicationsFeb 25 2013Here we present a fast review of some of developments and new results concerning applications of gravity in the context of the AdS/CFT correspondence, in brane world perturbations as well as in holographic superconductors. We also discuss the structure ... More
Jarzynski equality for superconducting optical cavities: an alternative path to determine Helmholtz free energyJan 04 2019A superconducting cavity model was proposed as a way to experimentally investigate the work performed in a quantum system. We found a simple mathematical relationship between the free energy variation and visibility measurement in quantum cavity context. ... More
The Resistive-WELL detector: a compact spark-protected single amplification-stage MPGDNov 10 2014In this work we present a novel idea for a compact spark-protected single amplification stage Micro-Pattern Gas Detector (MPGD). The detector amplification stage, realized with a structure very similar to a GEM foil, is embedded through a resistive layer ... More
Superconductivity in the vicinity of a ferroelectric quantum phase transitionJan 24 2018Feb 06 2018Superconductivity has been observed in doped SrTiO$_3$ at charge-carrier densities below 10$^{18}$ cm$^{-3}$, where the density of states at the Fermi level of the itinerant electrons is several orders of magnitude lower than that of conventional metals. ... More
Tunneling probability for the birth of an asymptotically DeSitter universeDec 05 2006Mar 28 2007In the present work, we quantize a closed Friedmann-Robertson-Walker model in the presence of a positive cosmological constant and radiation. It gives rise to a Wheeler-DeWitt equation for the scale factor which has the form of a Schr\"{o}dinger equation ... More
Clifford Valued Differential Forms, Algebraic Spinor Fields, Gravitation, Electromagnetism and "Unified" TheoriesNov 04 2003Dec 08 2004In this paper we show how to describe the general theory of a linear metric compatible connection with the theory of Clifford valued differential forms. This is done by realizing that for each spacetime point the algebra of Clifford bivectors is isomorphic ... More
Stability Analysis and Area Spectrum of 3-Dimensional Lifshitz Black HolesOct 21 2011Jan 03 2012In this work, we probe the stability of a $z=3$ three-dimensional Lifshitz black hole by using scalar and spinorial perturbations. We found an analytical expression for the quasinormal frequencies of the scalar probe field, which perfectly agree with ... More
A Gronwall inequality and the Cauchy-type problem by means of $ψ$-Hilfer operatorSep 12 2017In this paper, we propose a generalized Gronwall inequality through the fractional integral with respect to another function. The Cauchy-type problem for a nonlinear differential equation involving the $\psi$-Hilfer fractional derivative and the existence ... More
On the $ψ$-Hilfer fractional derivativeAug 17 2017In this paper we introduce a new fractional derivative with respect to another function the so-called $\psi$-Hilfer fractional derivative. We discuss some properties and important results of the fractional calculus. In this sense, we present some uniformly ... More
Stability of the fractional Volterra integro-differential equation by means of $ψ-$Hilfer operatorApr 07 2018In this paper, using the Riemann-Liouville fractional integral with respect to another function and the $\psi-$Hilfer fractional derivative, we propose a fractional Volterra integral equation and the fractional Volterra integro-differential equation. ... More
New Lagrange multipliers for the time fractional Burgers' equationAug 29 2015Using the fractional derivative, considered in the Caputo sense, we study an analytical technique associated with the variational iteration method for the fractional generalized $\alpha$-time Burgers' equation with $\alpha>0$ and obtain approximate solutions ... More
Final Stages of N-body Star Cluster EncountersOct 11 1999We performed numerical simulations of star cluster encounters with Hernquist's TREECODE in a CRAY YMP-2E computer. We used different initial conditions (relative positions and velocities, cluster sizes, masses and concentration degrees) with total number ... More
The low surface brightness dwarf members of nearby groups of galaxiesMar 19 2003We present the photometric and spectroscopic results of a survey done in a wide-field area of nearby groups and poor clusters. The main goals are identifying and characterizing the properties of low-surface-brightness dwarf galaxies and determining the ... More
Families of bipartite states classifiable by the positive partial transposition criterionJun 06 2009Nov 22 2010We construct a family of bipartite states of arbitrary dimension whose eigenvalues of the partially transposed matrix can be inferred directly from the block structure of the global density matrix. We identify from this several subfamilies in which the ... More
Leibniz type rule: $Ψ-$Hilfer fractional derivativeNov 07 2018In this paper, we present the Leibniz rule for the $\Psi-$Hilfer ($\Psi-$H) fractional derivative in two versions, the first in relation to $\Psi-$RL fractional derivative and the second in relation to the $\Psi-$H fractional derivative. In this sense, ... More
Electric field induced inversion of the sign of half-integer disclinations in 2D nematic liquid crystalsNov 25 2010We study the effect of the rotation of an external electric field on the dynamics of half-integer disclination networks in two dimensional nematic liquid crystals with a negative dielectric anisotropy using LICRA, a LIquid CRystal Algorithm developed ... More
Asymptotic behavior of the entropy of chains placed on stripesJun 27 2007By using the transfer matrix approach, we investigate the asymptotic behavior of the entropy of flexible chains with $M$ monomers each placed on stripes. In the limit of high density of monomers, we study the behavior of the entropy as a function of the ... More