Results for "Minos A. Neto"

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Bosonic Dirac Materials on a honeycomb antiferromagnetic Ising modelApr 12 2019Motivated by the recent proposal of Bosonic Dirac materials (BDM), we revisited the Ising model on a honeycomb lattice in the presence of the longitudinal and transverse fields. We apply linear spin-wave theory to obtain the magnon dispersion and its ... More
A new effective-field technique for the ferromagnetic spin-1 Blume-Capel model in a transverse crystal fieldJun 11 2017A new approximating technique is developed so as to study the quantum ferromagnetic spin-1 Blume-Capel model in the presence of a transverse crystal field in the square lattice. Our proposal consists of approaching the spin system by considering islands ... More
An individual based model with global competition interaction: fluctuations effects in pattern formationApr 02 2007Feb 27 2008We present some numerical results obtained from a simple individual based model that describes clustering of organisms caused by competition. Our aim is to show how, even when a deterministic description developed for continuum models predicts no pattern ... More
Phase diagrams of the transverse Ising antiferromagnet in the presence of the longitudinal magnetic fieldJul 09 2012In this paper we study the critical behavior of the two-dimensional antiferromagnetic Ising model in both uniform longitudinal ($H$) and transverse ($\Omega $) magnetic fields. Using the effective-field theory (EFT) with correlation in single site cluster ... More
Entropy of polydisperse chains: solution on the Bethe latticeMar 04 2008May 21 2008We consider the entropy of polydisperse chains placed on a lattice. In particular, we study a model for equilibrium polymerization, where the polydispersivity is determined by two activities, for internal and endpoint monomers of a chain. We solve the ... More
Entropy of polydisperse chains: solution on the Husimi latticeSep 27 2012Jan 09 2013We consider the entropy of polydisperse chains placed on a lattice. In particular, we study a model for equilibrium polymerization, where the polydispersivity is determined by two activities, for internal and endpoint monomers of a chain. We solve the ... More
Cooper-pair size and binding energy for unconventional superconducting systemsJan 16 2018The main proposal of this paper is to analyze the size of the Cooper pairs composed by unbalanced mass fermions from different electronic bands along the BCS-BEC crossover and study the binding energy of the pairs. We are considering an interaction between ... More
An Effective Torsion Model For Extra Gauge Bosons and Their Mass CorrectionsNov 07 2012LHC provides a excellent laboratory to probe massive gravitons effects in scenarios with low scale gravity up to several Tev. Based on this fact, in the present work we are interested in analyzing the possible constraints on the free parameters of the ... More
Finite RotationsNov 16 1998We present an elementary discussion of two basic properties of angular displacements, namely, the anticommutation of finite rotations and the commutation of infinitesimal rotations, and show how commutation is achieved as the angular displacements get ... More
Magnetization plateaus in the antiferromagnetic Ising chain with single-ion anisotropy and quenched disorderMay 15 2015We have studied the presence of plateaus on the low-temperature magnetization of an antiferromagnetic spin-1 chain, as an external uniform magnetic field is varied. A crystal-field interaction is present in the model and the exchange constants follow ... More
A mean-field approach applied for the ferromagnetic spin-1 Blume-Capel modelJul 05 2016We applied a mean-field approach associated to Monte Carlo simulations in order to study the spin-1 ferromagnetic Blume-Capel model in the square and the linear lattice. This new technique, which we call MFT-MC, determines the molecular field as the magnetization ... More
Comment on "Effects of cosmic-string framework on the thermodynamical properties of anharmonic oscillator using the ordinary statistics and the q-deformed superstatistics approaches"Apr 06 2018We point out a misleading treatment in a recent paper published in this Journal [Eur. Phys. J. C (2018)78:106] regarding solutions for the Schr\"{o}dinger equation with a anharmonic oscillator potential embedded in the background of a cosmic string mapped ... More
Confined magneto-optical waves in grapheneFeb 08 2012May 15 2012The electromagnetic mode spectrum of single-layer graphene subjected to a quantizing magnetic field is computed taking into account intraband and interband contributions to the magneto-optical conductivity. We find that a sequence of weakly decaying quasi-transverse-electric ... More
Could Geoneutrinos Interact With the Geomagnetic Field?Aug 14 2015In the present paper, we consider the possibility of interaction between geoneutrinos and the geomagnetic field, by adopting an approach based on the Dirac's equation with a non-minimal coupling that accounts for the magnetic interaction of the massive ... More
Conductance quantization in mesoscopic grapheneDec 19 2005May 14 2006Using a generalized Landauer approach we study the non-linear transport in mesoscopic graphene with zig-zag and armchair edges. We find that for clean systems, the low-bias low-temperature conductance, G, of an armchair edge system in quantized as G/t=4 ... More
Dirac Fermion Confinement in GrapheneMar 28 2006Apr 03 2006We study the problem of Dirac fermion confinement in graphene in the presence of a perpendicular magnetic field B. We show, analytically and numerically, that confinement leads to anomalies in the electronic spectrum and to a magnetic field dependent ... More
Electronic Properties of Two-Dimensional CarbonJun 27 2005We present a theoretical description of the electronic properties of graphene in the presence of disorder, electron-electron interactions, and particle-hole symmetry breaking. We show that while particle-hole asymmetry, long-range Coulomb interactions, ... More
Coulomb's law modification driven by a logarithmic electrodynamicsNov 07 2018We examine physical aspects for the electric version of a recently proposed logarithmic electrodynamics, for which the electric field of a point-like charge is finite at the origin. It is shown that this electrodynamics displays the vacuum birefringence ... More
f-Sum Rule and Unconventional Spectral Weight Transfer in GrapheneJun 10 2008Sep 01 2008We derive and analyze the f-sum rule for a two-dimensional (2D) system of interacting electrons whose behavior is described by the Dirac equation. We apply the sum rule to analyze the spectral weight transfer in graphene within different approximations ... More
Variational Procedure for Higher-Derivative Mechanical Models in a Fractional Integral FrameworkAug 18 2018We present both the Lagrangian and Hamiltonian procedures for treating higher-order equations of motion for mechanical models by adopting the Riemann-Liouville Fractional integral to describe their action. We point out and discuss its efficacy and difficulties. ... More
Fractional Canonical Quantization: a Parallel with NoncommutativityAug 10 2012Feb 13 2014Adopting a particular approach to fractional calculus, this paper sets out to build up a consistent extension of the Faddeev-Jackiw (or Symplectic) algorithm to carry out the quantization procedure of coarse-grained models in the standard canonical way. ... More
Conductivity of suspended and non-suspended graphene at finite gate voltageSep 15 2008We compute the DC and the optical conductivity of graphene for finite values of the chemical potential by taking into account the effect of disorder, due to mid-gap states (unitary scatterers) and charged impurities, and the effect of both optical and ... More
Electronic Properties of Disordered Two-Dimensional CarbonDec 05 2005Two-dimensional carbon, or graphene, is a semi-metal that presents unusual low-energy electronic excitations described in terms of Dirac fermions. We analyze in a self-consistent way the effects of localized (impurities or vacancies) and extended (edges ... More
Multicritical behavior of the two-dimensional transverse Ising metamagnet in a longitudinal magnetic fieldJul 13 2016Magnetic phenomena of the superantiferromagnetic Ising model in both uniform longitudinal ($H$) and transverse ($\Omega $) magnetic fields are studied by employing a mean-field variational approach based on Peierls-Bogoliubov inequality for the free energy. ... More
The Rubber Band Revisited: Wang-Landau SimulationJul 09 2012In this work we apply Wang-Landau simulations to a simple model which has exact solutions both in the microcanonical and canonical formalisms. The simulations were carried out by using an updated version of the Wang-Landau sampling. We consider a homopolymer ... More
The magnetic susceptibility on the transverse antiferromagnetic Ising model: Analysis of the reentrant behaviourMay 19 2016We study the three-dimensional antiferromagnetic Ising model in both uniform longitudinal ($H$) and transverse ($\Omega $) magnetic fields by using the effective-field theory with finite cluster $N=1$ spin (EFT-1). We analyzed the behavior of the magnetic ... More
Edge and Surface States in the Quantum Hall Effect in GrapheneSep 27 2005May 15 2006We study the integer and fractional quantum Hall effect on a honeycomb lattice at half-filling (graphene) in the presence of disorder and electron-electron interactions. We show that the interactions between the delocalized chiral edge states (generated ... More
Coulomb Interactions and Ferromagnetism in Pure and Doped GrapheneJul 03 2005Feb 24 2006We study the presence of ferromagnetism in the phase diagram of the two-dimensional honeycomb lattice close to half-filling (graphene) as a function of the strength of the Coulomb interaction and doping. We show that exchange interactions between Dirac ... More
Results from the MINOS Experiment and New MINOS+ DataJul 30 2015The MINOS experiment took data for seven years between May 2005 and April 2012. Since then it has been reborn as the new MINOS+ experiment in the upgraded medium energy NuMI beam and started taking data in September 2013. An update to the MINOS standard ... More
Spin-1/2 anisotropic Heisenberg antiferromagnet with Dzyaloshinskii-Moriya interaction via mean-field approximationFeb 20 2018The spin-1/2 anisotropic Heisenberg model with antiferromagnetic exchange interactions in the presence of a external magnetic field and a Dzyaloshinskii-Moriya interaction is studied by employing the usual mean-field approximation. The magnetic properties ... More
Thermodynamic properties of rod-like chains: entropic sampling simulationsMay 17 2016In this work we apply entropic sampling simulations to a three-state model which has exact solutions in the microcanonical and grand-canonical ensembles. We consider $N$ chains placed on an unidimensional lattice, such that each site may assume one of ... More
Qualitative aspects of the phase diagram of J1-J2 model on the cubic latticeAug 27 2012Jul 17 2013The qualitative aspects of the phase diagram of the Ising model on the cubic lattice, with ferromagnetic nearest-neighbor interactions ($J_{1}$) and antiferromagnetic next-nearest-neighbor couplings ($J_{2}$) are analyzed in the plane temperature versus ... More
Phase transition induced for external field in tree-dimensional isotropic Heisenberg antiferromagnetJun 22 2017In this paper, we report mean-field and effective-field renormalization group calculations on the isotropic Heisenberg antiferromagnetic model under a longitudinal magnetic field. As is already known, these methods, denoted by MFRG and EFRG, are based ... More
Topologically Massive Spin-1 Particles and Spin-Dependent PotentialsNov 14 2014Apr 27 2015We investigate the role played by particular field representations of an intermediate massive spin-1 boson in the context of spin-dependent interparticle potentials between fermionic sources in the limit of low momentum transfer. The comparison between ... More
Functional Bosonization of Non-Relativistic Fermions in $(2+1)$ DimensionsJul 13 1999Jun 02 2000We analyze the universality of the bosonization rules in non-relativistic fermionic systems in $(2+1)d$. We show that, in the case of linear fermionic dispersion relations, a general fermionic theory can be mapped into a gauge theory in such a way that ... More
The Ising antiferromagnet on an anisotropic simple cubic lattice in the presence of a magnetic fieldJun 27 2012We have studied the anisotropic three-dimensional nearest-neighbor Ising model with competitive interactions in an uniform longitudinal magnetic field $H$. The model consists of ferromagnetic interaction $J_{x}(J_{z})$ in the $x(z)$ direction and antiferromagnetic ... More
The spin-3/2 Blume-Capel model with competing short- and long-range interactionsFeb 20 2016The phase diagrams of the spin-$3/2$ Blume-Capel model with competing short and long-range interactions were studied through the free energy density obtained by analytical methods. The competition emerges when positive short-range interactions of strength ... More
M2-brane Dynamics in the Classical Limit of the BMN Matrix ModelJul 10 2017We investigate the large-N limit of the BMN matrix model by analyzing the dynamics of ellipsoidal M2-branes that spin in the 11-dimensional maximally supersymmetric SO(3)xSO(6) plane-wave background. We identify finite-energy solutions by specifying the ... More
Coulomb Drag and High Resistivity Behavior in Double Layer GrapheneMay 26 2011Jun 13 2011We show that Coulomb drag in ultra-clean graphene double layers can be used for controlling the on/off ratio for current flow by tunning the external gate voltage. Hence, although graphene remains semi-metallic, the double layer graphene system can be ... More
Optical Properties of Strained GrapheneDec 01 2010The optical conductivity of graphene strained uniaxially is studied within the Kubo-Greenwood formalism. Focusing on inter-band absorption, we analyze and quantify the breakdown of universal transparency in the visible region of the spectrum, and analytically ... More
Theory of Scanning Tunneling Spectroscopy of Magnetic Adatoms in GrapheneJun 16 2009Nov 11 2009We examine theoretically the signatures of magnetic adatoms in graphene probed by scanning tunneling spectroscopy (STS). When the adatom hybridizes equally with the two graphene sublattices, the broadening of the local adatom level is anomalous and can ... More
Optimizing optical tweezing with directional scattering in composite microspheresJun 19 2018Trapping of microspheres with a single focused laser beam is usually limited to materials with relative refractive indexes slightly larger than one. We show that directional light scattering can be employed to optically trap high-index materials. For ... More
A residual for outlier identification in zero adjusted regression modelsDec 18 2018Zero adjusted regression models are used to fit variables that are discrete at zero and continuous at some interval of the positive real numbers. Diagnostic analysis in these models is usually performed using the randomized quantile residual, which is ... More
Comparative aspects of spin-dependent interaction potentials for spin-1/2 and spin-1 matter fieldsOct 12 2015Dec 31 2016This paper sets out to establish a comparative study between classes of spin- and velocity-dependent potentials for spin-1/2 and spin-1 matter currents/sources in the non-relativistic regime. Both (neutral massive) scalar and vector particles are considered ... More
Generalized spectral method for near-field optical microscopyMar 01 2015May 22 2015Electromagnetic interaction between a sub-wavelength particle (the `probe') and a material surface (the `sample') is studied theoretically. The interaction is shown to be governed by a series of resonances corresponding to surface polariton modes localized ... More
Electronic compressibility of a graphene bilayerJun 15 2007Mar 31 2008We calculate the electronic compressibility arising from electron-electron interactions for a graphene bilayer within the Hartree-Fock approximation. We show that, due to the chiral nature of the particles in this system, the compressibility is rather ... More
Condensation of Vortex-Strings: Effective Potential Contribution Through Dual ActionsApr 09 2007Topological excitations are believed to play an important role in different areas of physics. For example, one case of topical interest is the use of dual models of quantum cromodynamics to understand properties of its vacuum and confinement through the ... More
Continuum Model of the Twisted BilayerFeb 06 2012The continuum model of the twisted graphene bilayer (Phys. Rev. Lett. 99, 256802, 2007) is extended to include all types of commensurate structures. The essential ingredient of the model, the Fourier components of the spatially modulated hopping amplitudes, ... More
A tight-binding approach to uniaxial strain in grapheneNov 26 2008Jul 15 2009We analyze the effect of tensional strain in the electronic structure of graphene. In the absence of electron-electron interactions, within linear elasticity theory, and a tight-binding approach, we observe that strain can generate a bulk spectral gap. ... More
Cancellations for Circle-valued Morse Functions via Spectral SequencesOct 27 2016In this article, a spectral sequence analysis of a filtered Novikov complex $(\mathcal{N}_{\ast}(f),\Delta)$ over $\mathbb{Z}((t))$ is developed with the goal of obtaining results relating the algebraic and dynamical settings. Specifically, the unfolding ... More
AC and DC Conductivity Anisotropies in Lightly Doped La(2-x)Sr(x)CuO(4)May 23 2008Jun 09 2008The AC and DC conductivity anisotropies in the low temperature orthorhombic phase of lightly doped La(2-x)Sr(x)CuO(4) are ascribed to the rotational symmetry broken, localized impurity states resulting from the trapping of doped holes by Sr ions. The ... More
Magnetic exchange mechanism for electronic gap opening in grapheneAug 19 2010Oct 08 2011We show within a local self-consistent mean-field treatment that a random distribution of magnetic adatoms can open a robust gap in the electronic spectrum of graphene. The electronic gap results from the interplay between the nature of the graphene sublattice ... More
On wavelets to select the parametric form of a regression modelSep 28 2018Let Y be a response variable related with a set of explanatory variables and let f1, f2, ..., fk be a set of the parametric forms representing a set of candidate's model. Let f* be the true model among the set of k plausible models. We discuss in this ... More
Van der Waals forces and electron-electron interactions in two strained graphene layersFeb 14 2014We evaluate the van der Waals (vdW) interaction energy at zero temperature between two undoped strained graphene layers separated by a finite distance. We consider the following three models for the anisotropic case: (a) where one of the two layers is ... More
Distortion of the perfect lattice structure in bilayer grapheneSep 29 2008We consider the instability of bilayer graphene with respect to a distorted configuration in the same spirit as the model introduced by Su, Schrieffer and Heeger. By computing the total energy of a distorted bilayer, we conclude that the ground state ... More
Localized Magnetic States in GrapheneFeb 12 2008Jul 12 2008We examine the conditions necessary for the presence of localized magnetic moments on adatoms with inner shell electrons in graphene. We show that the low density of states at the Dirac point, and the anomalous broadening of the adatom electronic level,lead ... More
Electronic properties of bilayer and multilayer grapheneDec 19 2007Jan 24 2008We study the effects of site dilution disorder on the electronic properties in graphene multilayers, in particular the bilayer and the infinite stack. The simplicity of the model allows for an easy implementation of the coherent potential approximation ... More
Exploration of Interesting Dense Regions in Spatial DataMar 10 2019Nowadays, spatial data are ubiquitous in various fields of science, such as transportation and the social Web. A recent research direction in analyzing spatial data is to provide means for "exploratory analysis" of such data where analysts are guided ... More
MINOS Search for Sterile NeutrinosOct 16 2011Using a NuMI beam exposure of 7.1 /times 10^20 protons-on-target, the MINOS long-baseline experiment has performed a search for active to sterile neutrino mixing over a distance of 735 km. Details of the analysis are provided, along with results from ... More
Faraday effect in graphene enclosed in an optical cavity and the equation of motion method for the study of magneto-optical transport in solidsSep 14 2011Jan 06 2012We show that by enclosing graphene in an optical cavity, giant Faraday rotations in the infrared regime are generated and measurable Faraday rotation angles in the visible range become possible. Explicit expressions for the Hall steps of the Faraday rotation ... More
Observation of the Kohn anomaly near the K point of bilayer grapheneJul 19 2009The dispersion of electrons and phonons near the K point of bilayer graphene was investigated in a resonant Raman study using different laser excitation energies in the near infrared and visible range. The electronic structure was analyzed within the ... More
NON-POLYNOMIAL LAGRANGIANS IN THE SKYRME MODELApr 03 1995We choose three different coupling constants for a particular higher-derivative term in the Skyrme model that allows the total Lagrangian to converge in a binomial, geometric and a logarithmic form. Improved numerical results are obtained.
Remarks on the Collective Quantization of the SU(2) Skyrme ModelJan 03 1994We point out the question of ordering momentum operator in the canonical \break quantization of the SU(2) Skyrme Model. Thus, we suggest a new definition for the momentum operator that may solve the infrared problem that appears when we try to minimize ... More
Unified description of the dc conductivity of monolayer and bilayer graphene at finite densities based on resonant scatterersOct 19 2010Apr 06 2011We show that a coherent picture of the dc conductivity of monolayer and bilayer graphene at finite electronic densities emerges upon considering that strong short-range potentials are the main source of scattering in these two systems. The origin of the ... More
Field dependence of the magnetic spectrum in anisotropic and Dzyaloshinskii-Moriya antiferromagnets: II. Raman spectroscopyFeb 28 2006Aug 02 2006We compare the theoretical predictions of the previous article [L. Benfatto and M. B. Silva Neto, cond-mat/0602419], with Raman spectroscopy experiments in Sr(2)CuO(2)Cl(2) and untwinned La(2)CuO(4) single crystals. We construct the magnetic point group ... More
Localized states at zigzag edges of bilayer grapheneJul 25 2007We report the existence of zero energy surface states localized at zigzag edges of bilayer graphene. Working within the tight-binding approximation we derive the analytic solution for the wavefunctions of these peculiar surface states. It is shown that ... More
An empirical study on the effects of different types of noise in image classification tasksSep 09 2016Image classification is one of the main research problems in computer vision and machine learning. Since in most real-world image classification applications there is no control over how the images are captured, it is necessary to consider the possibility ... More
Particle-hole level densities in deformed nucleiJul 27 1999Microscopic Combinatorial approach is used to calculate the state and level densities with fixed exciton numbers, in some actinide nuclei. Deformed Saxon-Woods shell model was used as a basis from which all posible configurations were generated. The pairing ... More
On String Tunneling in Power Law Inflationary UniversesAug 31 1993We consider the evolution of circular string loops in power law expanding universes represented by a spatially flat Friedman-Robertson-Walker metric with scale factor $a(t)\propto t^p$ where $t$ is the cosmic time and $p\geq 0$. Our main result is the ... More
Observation of Intra- and Inter-band Transitions in the Optical Response of GrapheneApr 15 2011The optical conductivity of freely suspended graphene was examined under non-equilibrium conditions using femtosecond pump-probe spectroscopy. We observed a conductivity transient that varied strongly with the electronic temperature, exhibiting a crossover ... More
KUKA Sunrise Toolbox: Interfacing Collaborative Robots with MATLABSep 05 2017Collaborative robots are increasingly present in our lives. The KUKA LBR iiwa equipped with the KUKA Sunrise.OS controller is a good example of a collaborative/sensitive robot. This paper presents a MATLAB Toolbox, the KUKA Sunrise Toolbox (KST), to interface ... More
Response to comment on "Broken translational and rotational symmetry via charge stripe order in underdoped YBa2Cu3O6+y"Feb 03 2016Fine questions our interpretation of unidirectional-stripes over bidirectional-checkerboard, and illustrates his criticism by simulating a momentum space structure consistent with our data and corresponding to a checkerboard-looking real space density. ... More
Current NuMI/MINOS Oscillation ResultsMay 15 2008The MINOS experiment is now making precise measurements of the nu_mu disappearance oscillations seen in atmospheric neutrinos, and will extend our reach towards the so far unseen theta_13 by looking for nu_e appearance in the nu_mu beam. It does so by ... More
Making graphene visibleMay 02 2007Sep 22 2007Microfabrication of graphene devices used in many experimental studies currently relies on the fact that graphene crystallites can be visualized using optical microscopy if prepared on top of silicon wafers with a certain thickness of silicon dioxide. ... More
Probing the Electronic Structure of Bilayer Graphene by Raman ScatteringAug 09 2007The electronic structure of bilayer graphene is investigated from a resonant Raman study using different laser excitation energies. The values of the parameters of the Slonczewski-Weiss-McClure model for graphite are measured experimentally and some of ... More
Does the Weyl ordering prescription lead to the correct energy levels for the quantum particle on the D-dimensional sphere ?Nov 24 1998Mar 01 1999The energy eigenvalues of the quantum particle constrained in a surface of the sphere of D dimensions embedded in a $R^{D+1}$ space are obtained by using two different procedures: in the first, we derive the Hamiltonian operator by squaring the expression ... More
Maximum-size antichains in random set-systemsApr 21 2014Nov 12 2015We show that, for $pn \to \infty$, the largest set in a $p$-random sub-family of the power set of $\{1, \ldots, n\}$ containing no $k$-chain has size $( k - 1 + o(1) ) p \binom{n}{n/2}$ with high probability. This confirms a conjecture of Osthus, and ... More
Tunable room-temperature ferromagnet using an iron-oxide and graphene oxide nanocompositeMar 03 2015Magnetic materials have found wide application ranging from electronics and memories to medicine. Essential to these advances is the control of the magnetic order. To date, most room-temperature applications have a fixed magnetic moment whose orientation ... More
Photocarrier relaxation in two-dimensional semiconductorsFeb 03 2014Two-dimensional (2D) crystals of semiconducting transition metal dichalcogenides (TMD) absorb a large fraction of incident photons in the visible frequencies despite being atomically thin. It has been suggested that the strong absorption is due to the ... More
The $SU(2)$ Global Anomaly Through Level CirclingSep 01 1993We discuss a novel manifestation of the $SU(2)$ global anomaly in an $SU(2)$ gauge theory with an odd number of chiral quark doublets and arbitrary Yukawa couplings. We argue that the massive 4-dim.($D=4$) Euclidean Dirac operator is nonhermitean with ... More
Quasi free electro fission of 238UFeb 18 2002We present the result of a theoretical study of the quasi free electrofission of $^{238}$U. The exclusive differential cross sections for the quasi free scattering reaction stage have been calculated in PWIA, using a Macroscopic-Microscopic approach for ... More
On the geometrical hypotheses underlying wave functions and their emerging dynamicsMar 08 2019Quantum and classical mechanics of non-relativistic particles are shown to be exceptional cases of a generalized dynamics described in terms of maps between two manifolds, the source being configuration space. The map equation automatically leads to a ... More
Candidate stellar occultations by large trans-neptunian objects up to 2015Apr 19 2012We study large trans-neptunian objects (TNOs) using stellar occultations. We derive precise astrometric predictions for stellar occultations by Eris, Haumea, Ixion, Makemake, Orcus, Quaoar, Sedna, Varuna, 2002 TX300, and 2003 AZ84 for 2011-2015. We construct ... More
Electron waves in chemically substituted grapheneMay 21 2007We present exact analytical and numerical results for the electronic spectra and the Friedel oscillations around a substitutional impurity atom in a graphene lattice. A chemical dopant in graphene introduces changes in the on-site potential as well as ... More
Electronic and plasmonic phenomena at graphene grain boundariesNov 26 2013Graphene, a two-dimensional honeycomb lattice of carbon atoms, is of great interest in (opto)electronics and plasmonics and can be obtained by means of diverse fabrication techniques, among which chemical vapor deposition (CVD) is one of the most promising ... More
Incomplete fusion versus breakup competition with weakly bound projectilesJul 04 2005The importance of the breakup channel in the vicinity of the Coulomb barrier (1<Ec.m./Vb<2) is investigated for the medium weight 6Li+59Co system. Three-body final-state analysis of light-particle coincident data was carried out to disentangle, for the ... More
Infrared nano-spectroscopy and imaging of collective superfluid excitations in conventional and high-temperature superconductorsJul 23 2014We investigate near-field infrared spectroscopy and superfluid polariton imaging experiments on conventional and unconventional superconductors. Our modeling shows that near-field spectroscopy can measure the magnitude of the superconducting energy gap ... More
Study of 9Be+12C elastic scattering at energies near the Coulomb barrierMar 01 2011In this work, angular distribution measurements for the elastic channel were performed for the 9Be+12C reaction at the energies ELab=13.0, 14.5, 17.3, 19.0 and 21.0 MeV, near the Coulomb barrier. The data have been analyzed in the framework of the double ... More
Dynamical Casimir effect with cylindrical waveguidesAug 03 2004I consider the quantum electromagnetic field in a coaxial cylindrical waveguide, such that the outer cylindrical surface has a time-dependent radius. The field propagates parallel to the axis, inside the annular region between the two cylindrical surfaces. ... More
Polydisperse chains placed on a one-dimensional latticeNov 28 2005Using a transfer matrix technique, we calculate the entropy of polydisperse chains placed on a one-dimensional lattice, as a function of the density of internal and endpoint monomers. The polydispersivity is determined considering different activities ... More
XMM-Newton temperature maps for five intermediate redshift clusters of galaxiesJul 27 2007We have analyzed XMM-Newton archive data for five clusters of galaxies (redshifts 0.223 to 0.313) covering a wide range of dynamical states, from relaxed objects to clusters undergoing several mergers. We present here temperature maps of the X-ray gas ... More
Reaction mechanisms in the 6Li+59Co systemNov 27 2008Feb 27 2009The reactions induced by the weakly bound 6Li projectile interacting with the intermediate mass target 59Co were investigated. Light charged particles singles and $\alpha$-$d$ coincidence measurements were performed at the near barrier energies E_lab ... More
Non-Fermi liquid behavior in U and Ce intermetallicsNov 06 1999Dec 06 1999In this paper we review the current experimental and theoretical situation of the description of non-Fermi liquid behavior (NFL) in U and Ce intermetallics. We focus on the magnetic and thermodynamic properties. We also discuss a recent theoretical interpretation ... More
Luttinger Stripes in AntiferromagnetsNov 19 1996We propose a model for the physics of stripes in antiferromagnets in which the stripes are described by Luttinger liquids hybridized with antiferromagnetic domains. Using bosonization techniques we study the model in the limit where the magnetic correlation ... More
Landau theory of phase separation in cupratesOct 03 1994I discuss the problem of phase separation in cuprates from the point of view of the Landau theory of Fermi liquids. I calculate the rate of growth of unstable regions for the hydrodymanics and collisionless limit and, in presence of long range Coulomb ... More
f(R) gravity with torsion and Lorentz violationMar 10 2017The Lounesto spinor classification is an important tool in fundamental physics, because it makes explicit the pleiade of spinors types, beyond the used in quantum field theory (QFT). In this work, we show how the classification emerges in two topics: ... More
Vortex Condensation in the Dual Chern-Simons Higgs ModelNov 06 2007Apr 26 2008The contribution of nontrivial vacuum (topological) excitations, more specifically vortex configurations of the self-dual Chern-Simons-Higgs model, to the functional partition function is considered. By using a duality transformation, we arrive at a representation ... More
Hadron Scattering Lengths in Lattice QCDJan 21 1995Lattice QCD calculation of s-wave hadron scattering lengths in the channels \pi-\pi, \pi-N, K-N, {\bar K}-N and N-N is carried out in the quenched QCD at $\beta=6/g^2=5.7$. A variant of the method of wall sourceis developed for this purpose, which reduces ... More
Bootstrap-based model selection criteria for beta regressionsMay 18 2014The Akaike information criterion (AIC) is a model selection criterion widely used in practical applications. The AIC is an estimator of the log-likelihood expected value, and measures the discrepancy between the true model and the estimated model. In ... More
Biased bilayer graphene: semiconductor with a gap tunable by electric field effectNov 13 2006Nov 16 2007We demonstrate that the electronic gap of a graphene bilayer can be controlled externally by applying a gate bias. From the magneto-transport data (Shubnikov-de Haas measurements of the cyclotron mass), and using a tight binding model, we extract the ... More