Results for "R. M. Gomes"

total 269301took 0.12s
On Higher Spatial Derivative Field TheoriesJul 29 2011Apr 23 2012In this work, we employ renormalization group methods to study the general behavior of field theories possessing anisotropic scaling in the spacetime variables. The Lorentz breaking symmetry that accompanies these models are either soft, if no higher ... More
On Ward Identities in Lifshitz-like Field TheoriesDec 16 2011Mar 09 2012In this work, we develop a normal product algorithm suitable to the study of anisotropic field theories in flat space, apply it to construct the symmetries generators and describe how their possible anomalies may be found. In particular, we discuss the ... More
Low-Energy Lorentz Invariance in Lifshitz Nonlinear Sigma ModelsApr 29 2016Jun 30 2016This work is dedicated to the study of both large-$N$ and perturbative quantum behaviors of Lifshitz nonlinear sigma models with dynamical critical exponent $z=2$ in 2+1 dimensions. We discuss renormalization and renormalization group aspects with emphasis ... More
Equivalence classes for gauge theoriesOct 04 2006In this paper we go deep into the connection between duality and fields redefinition for general bilinear models involving the 1-form gauge field $A$. A duality operator is fixed based on "gauge embedding" procedure. Dual models are shown to fit in equivalence ... More
Competing interactions and the Lifshitz-type Nonlinear Sigma ModelMay 16 2013Aug 01 2013We establish the equivalence between the continuum limit of the quantum spherical model with competing interactions, which is relevant to the investigation of Lifshitz points, and the O(N) nonlinear sigma model with the addition of higher order spatial ... More
Stochastic Quantization of the Spherical Model and SupersymmetryNov 21 2012Sep 20 2013We use the stochastic quantization method to construct a supersymmetric version of the quantum spherical model. This is based on the equivalence between the Brownian motion described by a Langevin equation and the supersymmetric quantum mechanics, which ... More
Supersymmetric Extension of the Quantum Spherical ModelMar 22 2012Jun 09 2012In this work, we present a supersymmetric extension of the quantum spherical model, both in components and also in the superspace formalisms. We find the solution for short/long range interactions through the imaginary time formalism path integral approach. ... More
Linking number from a topologically massive p-form theoryMar 18 2004Mar 30 2005We show that the linking number of two homologically trivial disjoint $p$ and $(D-p-1)$-dimensional submanifolds of a $D$-dimensional manifold can be derived from the topologically massive $BC$ theory in low energy regime.
Lorentz violating effects on a quantized two-level systemMar 27 2008In this work, we consider the effects of the Lorentz-violating (LV) term $ v_{\mu}\bar{\psi}\gamma ^{\mu}\psi $ belonging to the fermion sector of the extended standard model on the dynamics of a quantum two-level system. We examine how its non-relativistic ... More
Duality and fields redefinition in three dimensionsMay 28 2004Dec 01 2004We analyze local fields redefinition and duality for gauge field theories in three dimensions. We find that both Maxwell-Chern-Simons and the Self-Dual models admits the same fields redefinition. Maxwell-Proca action and its dual also share this property. ... More
Nonanomalous measure of realism-based nonlocalitySep 14 2017Feb 05 2018Based on a recently proposed model of physical reality and an underlying criterion of nonlocality for contexts [A. L. O. Bilobran and R. M. Angelo, Europhys. Lett. {\bf 112}, 40005 (2015)], we introduce a quantifier of realism-based nonlocality for bipartite ... More
Nucleation of Superconductivity in Thin Type-I FoilsJul 27 2006Mar 26 2007The nucleation of the superconductive phase in macroscopic type-I foils in a slow, continuously decreasing perpendicular magnetic field is observed to first occur at the field $H_{c3}$, and reinitiate at $H_{c2}$. The observed variation of $H_{c2}$ with ... More
Resilience of realism-based nonlocality to local disturbanceMay 04 2018Jan 21 2019Employing a procedure called monitoring---via a completely positive trace-preserving map that is able to interpolate between weak and projective measurements---we investigate the resilience of the recently proposed realism-based nonlocality to local and ... More
Solution of the quantum harmonic oscillator plus a delta-function potential at the origin: The oddness of its even-parity solutionsSep 14 2011We derive the energy levels associated with the even-parity wave functions of the harmonic oscillator with an additional delta-function potential at the origin. Our results bring to the attention of students a non-trivial and analytical example of a modification ... More
Tunneling of Dirac electrons through spatial regions of finite massMay 14 2008We study the tunneling of chiral electrons in graphene through a region where the electronic spectrum changes from the usual linear dispersion to a hyperbolic dispersion, due to the presence of a gap. It is shown that contrary to the tunneling through ... More
A remark concerning divergence accuracy order for H(div)-conforming finite element flux approximationsAug 10 2018The construction of finite element approximations in $\mathbf{H}(\mbox{div}, {\Omega})$ usually requires the Piola transformation to map vector polynomials from a master element to vector fields in the elements of a partition of the region {\Omega}. It ... More
Magnetism in strained graphene dotsSep 25 2009Oct 22 2009We study the magnetization of square and hexagonal graphene dots. It is shown that two classes of hexagonal dots have a second order phase transition at a critical Hubbard energy $U$, whoose value is similar to the one in bulk graphene, albeit the dots ... More
New Phenomenon of Nonlinear Regge Trajectory and Quantum Dual String TheoryMay 26 1994The relation between the spin and the mass of an infinite number of particles in a $q$-deformed dual string theory is studied. For the deformation parameter $q$ a root of unity, in addition to the relation of such values of $q$ with the rational conformal ... More
Aspects of Emergent SymmetriesOct 15 2015Mar 08 2016These are intended to be review notes on emergent symmetries, i.e., symmetries which manifest themselves in specific sectors of energy in many systems. The emphasis is on the physical aspects rather than computation methods. We include some background ... More
Dual Spaces of Resonance In Thick $p-$BranesOct 07 2010Feb 21 2011In this work we consider $q-$form fields in a $p-$brane embedded in a $D=(p+2)$ space-time. The membrane is generated by a domain wall in a Randall-Sundrum-like scenario. We study conditions for localization of zero modes of these fields. The expression ... More
A superspace gauge-invariant formulation of a massive tridimensional 2-form fieldApr 30 2000By dimensional reduction of a massive supersymmetric B$\wedge $F theory, a manifestly N=1 supersymmetric completion of a massive antisymmetric tensor gauge theory is constructed in (2+1) dimensions. In the N=1-D=3 superspace, a new topological term is ... More
Evolution of the magnetism of Tb(Co_{x}Ni_{1-x})_{2}B_{2}CJul 02 2012The magnetic properties of polycrystalline Tb(Co_{x}Ni_{1-x})_{2}B_{2}C (x=0.2,0.4,0.6,0.8) samples were probed by magnetization, specific heat, ac susceptibility, and resistivity techniques. For x{\neq}0.4, the obtained curves are consistent with the ... More
Lorentz-violating effects on topological defects generated by two real scalar fieldsJan 28 2010The influence of a Lorentz-violation on soliton solutions generated by a system of two coupled scalar fields is investigated. Lorentz violation is induced by a fixed tensor coefficient that couples the two fields. The Bogomol'nyi method is applied and ... More
Hadamard Type Variation Formulas for the Eigenvalues of the $η$-Laplacian and ApplicationsOct 23 2015Oct 31 2016In this paper we consider an analytic family of Riemannian structures on a compact smooth manifold $M$ with boundary. We impose the Dirichlet condition to the $\eta$-Laplacian and show the existence of analytic curves of its eigenfunctions and eigenvalues. ... More
Hadamard type variation formulas for the eigenvalues of the $η$-Laplacian and applicationsOct 23 2015Feb 24 2019We consider an analytic family of Riemannian metrics on a compact smooth manifold $M$. We assume the Dirichlet boundary condition for the $\eta$-Laplacian and obtain Hadamard type variation formulas for analytic curves of eigenfunctions and eigenvalues. ... More
Fermion localization and resonances on two-field thick branesJan 22 2009Jul 05 2009We consider $(4,1)$-dimensional branes constructed with two scalar fields $\phi$ and $\chi$ coupled to a Dirac spinor field by means of a general Yukawa coupling. The equation of motion for the coefficients of the chiral decomposition of the spinor in ... More
Metal-Ferroelectric-Metal structures with Schottky contacts: II. Analysis of the experimental current-voltage and capacitance-voltage characteristics of Pb(Zr,Ti)O3 thin filmsAug 24 2005A modified model of metal-semiconductor contacts is applied to analyze the capacitance-voltage and current-voltage characteristics of metal-ferroelectric-metal structures. The ferroelectric polarization is considered as a sheet of surface charge situated ... More
Gauge propagator and physical consistency of the CPT-even part of the Standard Model ExtensionSep 02 2009Jan 04 2010In this work, we explicitly evaluate the gauge propagator of the Maxwell theory supplemented by the CPT-even term of the SME. First, we specialize our evaluation for the parity-odd sector of the tensor $W_{\mu \nu \rho \sigma}$,\ using a parametrization ... More
Stationary solutions for the parity-even sector of the CPT-even and Lorentz-covariance-violating term of the standard model extensionDec 09 2008Jun 25 2009In this work, we focus on some properties of the parity-even sector of the CPT-even electrodynamics of the standard model extension. We analyze how the six non-birefringent terms belonging to this sector modify the static and stationary classical solutions ... More
Complete Fusion of Weakly Bound Cluster-Type Nuclei at Near Barrier EnergiesMar 19 2013We consider the influence of breakup channels on the complete fusion of weakly bound cluster-type systems in terms of dynamic polarization potentials. It is argued that the enhancement of the cross section at sub-barrier energies may be consistent with ... More
Sliding susceptibility of a rough cylinder on a rough inclined perturbed surfaceFeb 24 2004A susceptibility function ${\chi}(L)$ is introduced to quantify some aspects of the intermittent stick-slip dynamics of a rough metallic cylinder of length $L$ on a rough metallic incline submitted to small controlled perturbations and maintained below ... More
Theoretical study of the elastic breakup of weakly bound nuclei at near barrier energiesOct 06 2015We have performed CDCC calculations for collisions of $^{7}$Li projectiles on $^{59}$Co, $^{144}$Sm and $^{208}$Pb targets at near-barrier energies, to assess the importance of the Coulomb and the nuclear couplings in the breakup of $^{7}$Li, as well ... More
Low temperature specific heat of the molecular cluster Fe$_{8}$: contribution of the local fieldDec 13 1999We present low temperature specific heat and ac-susceptibility measurements on Fe$_{8}$ powdered sample. Below 1.3 K, superparamagnetic blocking effects as well as an excess specific heat contribution are evident. The latter is attributed to a splitting ... More
Converting ECG and other paper legated biomedical maps into digital signalsFeb 20 2015Mar 05 2015This paper presents a digital signal processing tool developed using MatlabTM, which provides a very low-cost and effective strategy for analog-to-digital conversion of legated paper biomedical maps without requiring dedicated hardware. This software-based ... More
Scaling laws for near barrier Coulomb and Nuclear BreakupSep 05 2013We investigate the nuclear and the Coulomb contributions to the breakup cross sections of $^6$Li in collisions with targets in different mass ranges. Comparing cross sections for different targets at collision energies corresponding to the same $E/V_{\mathrm{\scriptscriptstyle ... More
The nuclear and Coulomb breakup of the weakly bound $^{6}$Li with targets in the range from A = 59 to 208Dec 13 2012We have performed CDCC calculations for the $^{6}$Li + $^{59}$Co, $^{144}$Sm and $^{208}$Pb systems, to investigate the dependence of the relative importance of nuclear and Coulomb breakup on the target charge (mass) at near barrier energies. The calculations ... More
An Oort cloud origin for the high-inclination, high-perihelion CentaursNov 30 2011We analyse the origin of three Centaurs with perihelia in the range 15 AU to 30 AU, inclinations above 70 deg and semi-major axes shorter than 100 AU. Based on long-term numerical simulations we conclude that these objects most likely originate from the ... More
Towards scaling cosmological solutions with full coupled Horndeski Lagrangian: the KGB modelJun 15 2013Mar 14 2014We study a general scalar field Lagrangian coupled with matter and linear in $\Box\phi$ (also called KGB model). Within this class of models, we find the most general form of the Lagrangian that allows for cosmological scaling solutions, i.e. solutions ... More
The general form of the coupled Horndeski Lagrangian that allows cosmological scaling solutionsNov 02 2015We consider the general scalar field Horndeski Lagrangian coupled to matter. Within this class of models, we present two results that are independent of the particular form of the model. First, we show that in a Friedmann-Robertson-Walker metric the Horndeski ... More
Theoretical model for the evolution of the linguistic diversityMay 27 2005Here we describe how some important scaling laws observed in the distribution of languages on Earth can emerge from a simple computer simulation. The proposed language dynamics includes processes of selective geographic colonization, linguistic anomalous ... More
Parameter Limits for Neutrino Oscillation with Decoherence in KamLANDMar 14 2016Apr 15 2016In the framework of quantum open systems we analyze data from KamLAND by using a model that considers neutrino oscillation in a three-family approximation with the inclusion of the decoherence effect. Using a $\chi^2$ test we find new limits for the decoherence ... More
Parameter Limits for Neutrino Oscillation with Decoherence in KamLANDMar 14 2016Apr 01 2017In the framework of quantum open systems we analyze data from KamLAND by using a model that considers neutrino oscillation in a three-family approximation with the inclusion of the decoherence effect. Using a $\chi^2$ test we find new limits for the decoherence ... More
A Multiple Dry Merger at z=0.18: Witnessing The Assembly of a Massive Elliptical GalaxyJun 10 2014Mergers of gas-poor galaxies, so-called dry mergers, may play a fundamental role in the assembly of the most massive galaxies, and therefore, in galaxy formation theories. Using the SDSS, we have serendipitously discovered a rare system in the observational ... More
Bloch BraneMar 15 2004May 06 2004We investigate a system described by two real scalar fields coupled with gravity in (4, 1) dimensions in warped spacetime involving one extra dimension. The results show that the parameter which controls the way the two scalar fields interact induces ... More
Extended solutions via the trial-orbit method for two-field modelsMay 01 2009In this work we investigate the presence of defect structures in models described by two real scalar fields. The coupling between the two fields is inspired on the equations for a multimode laser, and the minimum energy trivial configurations are shown ... More
Tuning in magnetic modes in Tb(Co_{x}Ni_{1-x})_{2}B_{2}C: from longitudinal spin-density waves to simple ferromagnetismMay 07 2012Neutron diffraction and thermodynamics techniques were used to probe the evolution of the magnetic properties of Tb(Co_{x}Ni_{1-x})_{2}B_{2}C. A succession of magnetic modes was observed as x is varied: the longitudinal modulated k=(0.55,0,0) state at ... More
Propagator in the Horava-Lifshitz gravityNov 24 2011Jul 11 2012In this paper it is studied the propagator for the modified theory of gravity proposed by Ho\vrava. We first calculate the propagator in the $\lambda=1$ case and show that the main poles that arise correspond to the spin two particle and scalar particle, ... More
Omori Law for Sliding of Blocks on Inclined Rough SurfacesFeb 24 2004Long sequences of slidings of solid blocks on an inclined rough surface submitted to small controlled perturbations are examined and scaling relations are found for the time distribution of slidings between pairs of large events as well as after and before ... More
Quantum control in foundational experimentsJan 29 2013Apr 27 2014We describe a new class of experiments designed to probe the foundations of quantum mechanics. Using quantum controlling devices, we show how to attain a freedom in temporal ordering of the control and detection of various phenomena. We consider wave-particle ... More
Continuous variable quantum computation with spatial degrees of freedom of photonsJun 15 2011We discuss the use of the transverse spatial degrees of freedom of photons propagating in the paraxial approximation for continuous variable information processing. Given the wide variety of linear optical devices available, a diverse range of operations ... More
Quantum teleportation in superconducting charge qubitsApr 15 2008Feb 22 2009In this paper we propose a scheme to implement a quantum teleportation based on the current experimental design [Nature (London) 431, 162 (2004); ibid 445, 515 (2007)] in which superconducting charge qubits are capacitively coupled to a single high-Q ... More
Enhancement of sub-barrier fusion of two-neutron halo nucleiSep 03 2010The tunneling of composite systems, where breakup may occur during the barrier penetration process is considered in connection with the fusion of halo-like radioactive, neutron- and proton-rich nuclei on heavy targets. The large amount of recent and new ... More
Breakup Threshold Anomaly: New Manifestation of the Dispersion RelationFeb 02 2005Apr 23 2007It is pointed out that the usual threshold anomaly, found operative in the energy behavior of the imaginary and real parts of the optical potential representing the elastic scattering of tightly bound nuclei at near- and below-barrier energies, suffers ... More
Hanbury Brown Twiss effect for ultracold quantum gasesAug 19 2005Sep 05 2006We have studied 2-body correlations of atoms in an expanding cloud above and below the Bose-Einstein condensation threshold. The observed correlation function for a thermal cloud shows a bunching behavior, while the correlation is flat for a coherent ... More
Slavnov-Taylor identities for noncommutative QED$_4$Feb 04 2010Feb 22 2010In this work we present an analysis of the one-loop Slavnov-Taylor identities in noncommutative QED$_4$. The vectorial fermion-photon and the triple photon vertex functions were studied, with the conclusion that no anomalies arise.
The three-dimensional non-anticommutative superspaceJul 13 2006Dec 06 2006We propose two alternative formulations for a three-dimensional non-anticommutative superspace in which some of the fermionic coordinates obey Clifford anticommutation relations. For this superspace, we construct the supersymmetry generators satisfying ... More
The Low Energy Limit of the Chern-Simons Theory Coupled to FermionsMar 27 1997We study the nonrelativistic limit of the theory of a quantum Chern--Simons field minimally coupled to Dirac fermions. To get the nonrelativistic effective Lagrangian one has to incorporate vacuum polarization and anomalous magnetic moment effects. Besides ... More
Testing CPT- and Lorentz-odd electrodynamics with waveguidesSep 15 2009Sep 17 2010We study CPT- and Lorentz-odd electrodynamics described by the Standard Model Extension. Its radiation is confined to the geometry of hollow conductor waveguide, open along $z$. In a special class of reference frames, with vanishing both 0-th and $z$ ... More
Scaling relations for diversity of languagesApr 27 2005The distribution of living languages is investigated and scaling relations are found for the diversity of languages as a function of the country area and population. These results are compared with data from Ecology and from computer simulations of fragmentation ... More
Reliable Entanglement Detection Under Coarse--Grained MeasurementsOct 22 2012Jun 17 2013We derive reliable entanglement witnesses for coarse--grained measurements on continuous variable systems. These witnesses never return a "false positive" for identification of entanglement, under any degree of coarse graining. We show that, even in the ... More
Experimental Observation of Quantum Chaos in a Beam of LightJul 23 2012Mar 06 2014The manner in which unpredictable chaotic dynamics manifests itself in quantum mechanics is a key question in the field of quantum chaos. Indeed, very distinct quantum features can appear due to underlying classical nonlinear dynamics. Here we observe ... More
Assessing the adequacy of the bare optical potential in near-barrier fusion calculationSep 23 2013We critically examine the differences among the different bare nuclear interactions used in near-barrier heavy ion fusion analysis and Coupled-Channels calculations, and discuss the possibility of extracting the barrier parameters of the bare potential ... More
Semi-empirical analysis of SDSS galaxies: I. Spectral synthesis methodDec 17 2004In this paper we investigate the power of spectral synthesis as a mean to estimate physical properties of galaxies. Spectral synthesis is nothing more than the decomposition of an observed spectrum in terms of a superposition of a base of simple stellar ... More
One-loop corrections in the z=3 Lifshitz extension of QEDSep 15 2018Nov 20 2018In this work we study a z=3 Horava-Lifshitz-like extension of QED in (3+1) dimensions. We calculate the one-loop radiative corrections to the two and three-point functions of the gauge and fermion fields. Such corrections were achieved using the perturbative ... More
The Slavnov-Taylor Identities for the 2+1 Dimensional Noncommutative CP$^{N-1}$ ModelJul 09 2010In the context of the $1/N$ expansion, the validity of the Slavnov-Taylor identity relating three and two point functions for the $2+1$ dimensional noncommutative CP$^{N-1} $ model is investigated, up to subleading $1/N$ order, in the Landau gauge.
On the radiative corrections in the Horava-Lifshitz z=2 QEDJul 05 2016Oct 19 2016We calculate one-loop contributions to the two and three point spinor-vector functions in z=2 Horava-Lifshitz QED. This allows us to obtain the anomalous magnetic moment.
On the effective potential, Horava-Lifshitz-like theories and finite temperatureNov 25 2013Nov 27 2013We calculate the one-loop effective potential at finite temperature for the Horava-Lifshitz-like QED and Yukawa-like theories for arbitrary values of the critical exponent and the space-time dimension. Additional remarks on the zero temperature situation ... More
On the effective potential for Horava-Lifshitz-like theoriesDec 09 2011Jun 22 2012We study the one-loop effective potential for some Horava-Lifshitz-like theories.
On the higher-derivative supersymmetric gauge theoryJan 04 2011We study the one-loop low-energy effective action for the higher-derivative superfield gauge theory coupled to a chiral matter.
Feynman propagator for the nonbirefringent CPT-even electrodynamics of the Standard Model ExtensionOct 13 2010Dec 08 2010The CPT-even gauge sector of the Standard Model Extension is composed of nineteen components comprised in the tensor $(K_{F})_{\mu \nu\rho\sigma}$, of \ which nine do not yield birefringence. In this work, we examine the Maxwell electrodynamics supplemented ... More
Bounded fitness landscapes and the evolution of the linguistic diversityOct 27 2005A simple spatial computer simulation model was recently introduced to study the evolution of the linguistic diversity. The model considers processes of selective geographic colonization, linguistic anomalous diffusion and mutation. In the approach, we ... More
Production of optical phase space vortices with non-locally distributed mode convertersJan 14 2011Optical vortices have been observed in a wide variety of optical systems. They can be observed directly in the wavefront of optical beams, or in the correlations between pairs of entangled photons. We present a novel optical vortex which appears in a ... More
Continuum-continuum coupling and polarization potentials for weakly bound systemJul 29 2009Aug 29 2009We investigate the influence of couplings among continuum states in collisions of weakly bound nuclei. For this purpose, we compare cross sections for complete fusion, breakup and elastic scattering evaluated by continuum discretized coupled channel (CDCC) ... More
On the generic higher-derivative N=2, d=3 gauge theoryJan 27 2014We formulate a generic $\mathcal{N}=2$ three-dimensional superfield higher-derivative gauge theory coupled to the matter, which, in certain cases reduces to the $\mathcal{N}=2$ three-dimensional scalar super-QED, or supersymmetric Maxwell-Chern-Simons ... More
Dynamical Lorentz and CPT symmetry breaking in a 4D four-fermion modelSep 18 2007Mar 27 2008In a 4D chiral Thirring model we analyse the possibility that radiative corrections may produce spontaneous breaking of Lorentz and CPT symmetry. By studying the effective potential, we verified that the chiral current $\bar\psi\gamma^{\mu} \gamma_5 \psi$ ... More
Superfield Effective Potential for the Supersymmetric Topologically Massive Gauge theory in Four DimensionsJan 16 2015We explicitly calculate the one-loop effective potential for the supersymmetric topologically massive gauge theory in four dimensions, where the chiral scalar superfield is directly coupled to the field strength for the gauge spinor superfield.
On the aether-like Lorentz-breaking action for the electromagnetic fieldAug 03 2010We study the generation of aether-like Lorentz-breaking actions in three, four and five dimensions via an appropriate Lorentz-breaking coupling of electromagnetic and spinor fields. Special attention is given to the four-dimensional case where we discuss ... More
On the aether-like Lorentz-breaking actionsNov 18 2009Feb 03 2010We demonstrate the generation of the CPT-even, aether-like Lorentz-breaking actions for the scalar and electromagnetic fields via their appropriate Lorentz-breaking coupling to spinor fields in three, four and five space-time dimensions. Besides, we show ... More
On the duality of three-dimensional superfield theoriesApr 04 2006Apr 26 2006Within the superfield approach, we consider the duality between the supersymmetric Maxwell-Chern-Simons and self-dual theories in three spacetime dimensions. Using a gauge embedding method, we construct the dual theory to the self-dual model interacting ... More
The Importance of Asymptotic Freedom for the Pseudocritical Temperature in Magnetized Quark MatterApr 15 2014Nov 24 2014Although asymptotic freedom is an essential feature of QCD, it is absent in effective chiral quark models like the Nambu--Jona-Lasinio and linear sigma models. In this work we advocate that asymptotic freedom plays a key role in the recently observed ... More
Influence of Lorentz-violating terms on a two-level systemJul 31 2007Dec 10 2007The influence of Lorentz- and CPT-violating terms of the extended Standard Model on a semi-classical two-level system is analyzed. It is shown that the Lorentz-violating background (when coupled with the fermion sector in a vector way) is able to induce ... More
Lorentz violation bounds on Bhabha scatteringApr 03 2012Oct 02 2012We investigate the effect of Lorentz-violating terms on Bhabha scattering in two distinct cases correspondent to vectorial and axial nonminimal couplings in QED. In both cases, we find significant modifications with respect to the usual relativistic result. ... More
An Entropic Einstein-Podolsky-Rosen CriterionJul 24 2009We propose an EPR inequality based on an entropic uncertainty relation for complementary continuous variable observables. This inequality is more sensitive than the previously established EPR inequality based on inferred variances, and opens up the possibility ... More
On the one-loop effective potential in the higher-derivative four-dimensional chiral superfield theory with a nonconventional kinetic termJan 21 2014We explicitly calculate the one-loop effective potential for a higher-derivative four-dimensional chiral superfield theory with a nonconventional kinetic term. We consider the cases of minimal and nonminimal general Lagrangians. In particular, we find ... More
All-loop finiteness of the two-dimensional noncommutative supersymmetric gauge theoryDec 09 2011May 13 2012Within the superfield approach, we discuss two-dimensional noncommutative super-QED. Its all-order finiteness is shown explicitly.
On the ambiguities in the effective action in Lorentz-violating gravityMay 28 2008Jun 02 2008We investigate the occurrence of ambiguities for Lorentz-violating gravitational Chern-Simons term. It turns out that this term is accompanied by a coefficient depending on an undetermined parameter, due to an arbitrariness in the choice of the conserved ... More
On the Horava-Lifshitz-like extensions of supersymmetric theoriesAug 27 2014Dec 02 2014Within the superfield approach, we formulate two different extensions of the Wess-Zumino model and super-QED with Horava-Lifshitz-like additive terms, discuss their quantum properties and calculate lower contributions to the effective action. In the case ... More
On duality of the noncommutative Maxwell-Chern-Simons theoryFeb 29 2008Mar 05 2008We study the possibility of establishing the dual equivalence between the noncommutative Maxwell-Chern-Simons theory and the noncommutative self-dual theory. It turns to be that whereas in the commutative case the Maxwell-Chern-Simons theory can be mapped ... More
On the induction of the four-dimensional Lorentz-breaking non-Abelian Chern-Simons actionApr 09 2007Jul 26 2007A four-dimensional Lorentz-breaking non-Abelian Chern-Simons like action is generated as a one-loop perturbative correction via an appropriate Lorentz-breaking coupling of the non-Abelian gauge field to the spinor field. This term is shown to be regularization ... More
Paramagnetic excited vortex states in superconductorsJun 21 2016We consider excited vortex states, which are vortex states left inside a superconductor once the external applied magnetic field is switched off and whose energy is lower than of the normal state. We show that this state is paramagnetic and develop here ... More
Spectral Synthesis of SDSS GalaxiesJun 17 2005We investigate the power of spectral synthesis as a mean to estimate physical properties of galaxies. Spectral synthesis is nothing more than the decomposition of an observed spectrum in terms of a superposition of a base of simple stellar populations ... More
Nontrivial temporal scaling in a Galilean stick-slip dynamicsFeb 07 2005Apr 18 2005We examine the stick-slip fluctuating response of a rough massive non-rotating cylinder moving on a rough inclined groove which is submitted to weak external perturbations and which is maintained well below the angle of repose. The experiments presented ... More
Statistics of the one-dimensional Riemann walkMar 09 2000The Riemann walk is the lattice version of the Levy flight. For the one-dimensional Riemann walk of Levy exponent 0<\alpha<2 we study the statistics of the support, i.e. the set of visited sites, after t steps. We consider a wide class of support related ... More
Observation of a Non-local Optical VortexFeb 10 2009Jul 24 2009We report the observation of an optical vortex in the correlations of photons produced from spontaneous parametric down-conversion. The singularity appears in a non-local coordinate plane consisting of one degree of freedom of each photon.
Supersymmetric Construction of W-Algebras from Super Toda and Wznw TheoriesJan 16 1992A systematic construction of super W-algebras in terms of the WZNW model based on a super Lie algebra is presented. These are shown to be the symmetry structure of the super Toda models, which can be obtained from the WZNW theory by Hamiltonian reduction. ... More
On the properties of the interstellar medium in extremely metal-poor blue compact dwarf galaxies: GMOS-IFU spectroscopy and SDSS photometry of the double-knot galaxy HS 2236+1344May 27 2014The main goal of this study is to carry out a spatially resolved investigation of the warm interstellar medium (ISM) in the extremely metal-poor Blue Compact Dwarf (BCD) galaxy HS 2236+1344. Special emphasis is laid on the analysis of the spatial distribution ... More
Synchronization by dynamical relaying in electronic circuit arraysJul 11 2006We experimentally study the synchronization of two chaotic electronic circuits whose dynamics is relayed by a third parameter-matched circuit, to which they are coupled bidirectionally in a linear chain configuration. In a wide range of operating parameters, ... More
The vacuum electromagnetic fields and the Schrodinger pictureOct 17 2005Apr 17 2006Several authors have used the Heisenberg picture to show that the atomic transitions, the stability of the ground state and the position-momentum commutation relation [x,p]=ih, can only be explained by introducing radiation reaction and vacuum electromagnetic ... More
On the effective superpotential in the supersymmetric Chern-Simons theory with matterOct 25 2012Dec 18 2012We develop a superfield approach to the effective potential in the supersymmetric Chern-Simons theory coupled to matter, and, in Landau gauge, calculate the one-loop Kahlerian effective potential and give some qualitative prescriptions for the two-loop ... More
Dynamical Lorentz symmetry breaking in 3D and charge fractionalizationSep 09 2008Mar 12 2009We analyze the breaking of Lorentz invariance in a 3D model of fermion fields self-coupled through four-fermion interactions. The low-energy limit of the theory contains various sub-models which are similar to those used in the study of the graphene or ... More