Results for "M. J. Felipe"

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The Cayley-Dickson process for dialgebrasSep 12 2012We adapt the algorithm of Kolesnikov and Pozhidaev, which converts a polynomial identity for algebras into the corresponding identities for dialgebras, to the Cayley-Dickson doubling process. We obtain a generalization of this process to the setting of ... More
A Dynamical Scheme for a Large CP-Violating PhaseMay 16 1997A dynamical scheme where the third generation of quarks plays a distinctive role is implemented. New interactions with a $\theta$ term induce the breaking of the electroweak symmetry and the top-bottom mass splitting. A large CP-violating phase naturally ... More
Square-free class sizes in products of groupsMar 24 2017We obtain some structural properties of a factorised group $G = AB$, given that the conjugacy class sizes of certain elements in $A\cup B$ are not divisible by $p^2$, for some prime $p$. The case when $G = AB$ is a mutually permutable product is especially ... More
A light stop and electroweak baryogenesisApr 30 1996The possibility of creating baryon asymmetry at the electroweak phase transition in the minimal supersymmetric standard model is considered for the case when right-handed squarks are much lighter than left-handed ones. It is shown that the usual requirement ... More
On zeros of irreducible characters lying in a normal subgroupFeb 08 2019Feb 13 2019Let $N$ be a normal subgroup of a finite group $G$. An element $g\in G$ such that $\chi(g)=0$ for some irreducible character $\chi$ of $G$ is called a vanishing element of $G$. The aim of this paper is to analyse the influence of the $\pi$-elements in ... More
Prime power indices in factorised groupsMay 02 2017Let the group $G = AB$ be the product of the subgroups $A$ and $B$. We determine some structural properties of $G$ when the $p$-elements in $A\cup B$ have prime power indices in $G$, for some prime $p$. More generally, we also consider the case that all ... More
Products of groups and class sizes of $π$-elementsDec 21 2018We provide structural criteria for some finite factorised groups $G = AB$ when the conjugacy class sizes in $G$ of certain $\pi$-elements in $A\cup B$ are either $\pi$-numbers or $\pi'$-numbers, for a set of primes $\pi$. In particular, we extend for ... More
Zeros of irreducible characters lying in a normal subgroupFeb 08 2019Let $N$ be a normal subgroup of a finite group $G$. An element $g\in G$ such that $\chi(g)=0$ for some irreducible character $\chi$ of $G$ is called a vanishing element of $G$. The aim of this paper is to analyse the influence of the $\pi$-elements in ... More
Zeros of irreducible characters in factorised groupsMar 01 2018An element $g$ of a finite group $G$ is said to be vanishing in $G$ if there exists an irreducible character $\chi$ of $G$ such that $\chi(g)=0$; in this case, $g$ is also called a zero of $G$. The aim of this paper is to obtain structural properties ... More
eta/s is critical (at phase transitions)Dec 11 2008The viscosity over entropy density ratio, or KSS number, can help isolate the critical point in the hadron phase-diagram in Relativistic Heavy Ion Collisions. We argue that this quantity does have a minimum at a phase transition or crossover. Although ... More
The effect of nonlocal confining kernels on magnetic chiral condensatesJul 30 2003Aug 08 2006The physics of spontaneous chiral symmetry breaking in the case of the simultaneous presence of a magnetic field and a fermionic quartic interaction is discussed for both local and nonlocal kernels in 2+1 and 3+1 dimensions. The approach is based on the ... 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
Heavy Quark FluorescenceMar 31 2010Jun 08 2010Heavy hadrons containing heavy quarks (for example, Upsilon-mesons) feature a scale separation between the heavy quark mass (about 4.5 GeV for the b-quark) and the QCD scale (about 0.3 GeV}) that controls effective masses of lighter constituents. Therefore, ... More
Bulk viscosity and energy-momentum correlations in high energy hadron collisionsJan 10 2011Jun 17 2011We show how the measurement of appropriately constructed particle-energy/momentum correlations allows access to the bulk viscosity of strongly interacting hadron matter in heavy ion collisions. This measurement can be performed by the LHC and RHIC experiments ... More
Synthetic polarimetric spectra from stellar prominencesOct 28 2016Stellar prominences detected in rapidly rotating stars serve as probes of the magnetism in the corona of cool stars. We have synthesized the temporal evolution of the Stokes profiles generated in the He I 10830 and 5876 A triplets during the rotation ... More
Shear and bulk viscosities of a photon gas at low temperatureJul 01 2013Sep 18 2013We explore the viscosities of a photon gas by means of the Euler-Heisenberg effective theory and quantum electrodynamics at zero electron chemical potential. We find parametric estimates that show a very large shear viscosity and an extremely small bulk ... More
Brief introduction to viscosity in hadron physicsSep 30 2010We introduce the concept of viscosity (both shear and bulk) in the context of hadron physics and in particular the meson gas, highlighting the current theoretical efforts to connect possible measurements of the viscosities to underlying physics such as ... More
Behaviour of the Absorptive Part of the W Electromagnetic VertexNov 26 1996The absorptive part of the $WW\gamma$ vertex induced by massive fermion loops is considered for different kinematical configurations. We show that the axial part of this vertex is different from zero not only when massive fermions are involved but also ... More
Is the standard Higgs scalar elementary?Dec 18 1995In the standard electroweak model, the measured top quark mass requires a sizeable Yukawa coupling to the fundamental scalar. This large coupling alone might induce a dynamical breaking of the electroweak symmetry as well as non-perturbative effects. ... More
Bulk viscosity of low-temperature strongly interacting matterMar 03 2011We study the bulk viscosity of a pion gas in unitarized Chiral Perturbation Theory at low and moderate temperatures, below any phase transition to a quark-gluon plasma phase. We argue that inelastic processes are irrelevant and exponentially suppressed ... More
Viscosity near phase transitionsSep 30 2010Probably the most enticing observation in theoretical physics during the last decade was the discovery of the great amount of consequences obtained from the AdS/CFT conjecture put forward by Maldacena. In this work we review how this correspondence can ... More
Minimum of $η/s$ and the phase transition of the Linear Sigma Model in the large-N limitJul 31 2009Dec 03 2009We reexamine the possibility of employing the viscosity over entropy density ratio as a diagnostic tool to identify a phase transition in hadron physics to the strongly coupled quark-gluon plasma and other circumstances where direct measurement of the ... More
$η/s$ and Phase TransitionsMar 22 2008Dec 09 2008We present a calculation of eta/s for the meson gas (zero baryon number), with the viscosity computed within unitarized NLO chiral perturbation theory, and confirm the observation that eta/s decreases towards the possible phase transition to a quark-gluon ... More
Coulomb gauge QCD as a tool for the excited spectrumSep 28 2010A distinct feature of Coulomb gauge QCD is that it can be formulated in terms of physical, transverse gluons and quarks alone. The state-counting is then transparent, and the gauge is suited for studies of the excited spectrum. Leaving aside exotic spectroscopy, ... More
Non quark-antiquark light meson spectroscopyNov 19 2003Dec 04 2003In this talk I comment on some theoretical expectations for exotic light meson spectroscopy below 2 GeV and their potential interest for a future energy upgrade of DAFNE.
Constraining gravity with hadron physics: neutron stars, modified gravity and gravitational wavesNov 11 2016The finding of Gravitational Waves by the aLIGO scientific and VIRGO collaborations opens opportunities to better test and understand strong interactions, both nuclear-hadronic and gravitational. Assuming General Relativity holds, one can constrain hadron ... More
The Barycenter Method for Direct OptimizationJan 31 2018A randomized version of the recently developed barycenter method for derivative-free optimization has desirable properties of a gradient search. We develop a complex version to avoid evaluations at high-gradient points. The method, applicable to non-smooth ... More
Charmonium's K2 peakJul 04 2005Jul 18 2005The newly reported Y(4260) becomes the second most massive state in the charmonium family. We argue that it displaces the psi(4415) as the (largely) 4s vector charmonium state, recall s-d wave interference to explain the lack of a signal in e-e+ to hadrons ... More
Constraining gravity with hadron physics: neutron stars, modified gravity and gravitational wavesNov 11 2016Nov 30 2016The finding of Gravitational Waves by the aLIGO scientific and VIRGO collaborations opens opportunities to better test and understand strong interactions, both nuclear-hadronic and gravitational. Assuming General Relativity holds, one can constrain hadron ... More
Universality of Planck's constant and a constraint from the absence of h_bar-induced neutrino mixingDec 12 2013You have probably often set hbar=1; but for what particle? I revisit here the possibility of a non-universal Planck-constant. Anomaly cancellation suggests that all particles in the same family perceive the same hbar at fixed charges e, g_w, g_s; the ... More
TOP-INDUCED ELECTROWEAK BREAKING IN THE MINIMAL SUPERSYMMETRIC STANDARD MODELApr 11 1995Severe constraints on parameters of the minimal supersymmetric standard model follow from a dynamical electroweak symmetry breaking mechanism dominated by top and stop loops. In particular, the lightest Higgs boson mass is expected to be smaller than ... More
Photonic spin Hall effect in bilayer graphene Moiré superlatticesNov 01 2018The formation of a superstructure - with a related Moir\'e pattern - plays a crucial role in the extraordinary optical and electronic properties of twisted bilayer graphene, including the recently observed unconventional superconductivity. Here we put ... More
D-meson diffusion in hadronic matterDec 12 2013We present effective-field-theory results with unitarized interactions on the D-meson transport coefficients in a gas populated by light mesons and baryons at finite temperature and baryochemical potential. The Fokker-Planck equation is used to compute ... More
Heavy flavor relaxation in a hadronic mediumMar 06 2013Charm and bottom transport coefficients in a medium constituted of light mesons, such as is formed in the hadronic phase of Heavy Ion Collisions, are obtained within an effective field theory approach implementing heavy quark symmetry and chiral symmetry ... More
Single Past Null Geodesic in the Lemaitre-Tolman-Bondi CosmologyDec 17 2013This work provides a general discussion of the spatially inhomogeneous Lema\^itre-Tolman-Bondi (LTB) cosmology, as well as its basic properties and many useful relevant quantities, such as the cosmological distances. We apply the concept of the single ... More
Polychromatic Grand UnificationMay 08 2003The possibility of achieving a gauge coupling grand unification by increasing the QCD degrees of freedom at higher energies is investigated. When confronted with precision low-energy data, the generic weak-mixing angle relation sin^2(theta_W) = N/2(N+1) ... More
Using highly excited baryons to catch the quark massDec 17 2009Jan 04 2010Chiral symmetry in QCD can be simultaneously in Wigner and Goldstone modes, depending on the part of the spectrum examined. The transition regime between both, exploiting for example the onset of parity doubling in the high baryon spectrum, can be used ... More
Transactional WaveCache: Towards Speculative and Out-of-Order DataFlow Execution of Memory OperationsDec 07 2007The WaveScalar is the first DataFlow Architecture that can efficiently provide the sequential memory semantics required by imperative languages. This work presents an alternative memory ordering mechanism for this architecture, the Transaction WaveCache. ... More
Heat conductivity of a pion gasFeb 13 2007We evaluate the heat conductivity of a dilute pion gas employing the Uehling-Uehlenbeck equation and experimental phase-shifts parameterized by means of the SU(2) Inverse Amplitude Method. Our results are consistent with previous evaluations. For comparison ... More
Couillard: Parallel Programming via Coarse-Grained Data-Flow CompilationSep 22 2011Data-flow is a natural approach to parallelism. However, describing dependencies and control between fine-grained data-flow tasks can be complex and present unwanted overheads. TALM (TALM is an Architecture and Language for Multi-threading) introduces ... More
Ambiguities in the gravitational correction of quantum electrodynamicsMay 30 2012May 09 2013We verify that quadratic divergences stemming from gravitational corrections to QED which have been conjectured to lead to asymptotic freedom near Planck scale are arbitrary (regularization dependent) and compatible with zero. Moreover we explicitly show ... More
Charm diffusion in a pion gas implementing unitarity, chiral and heavy quark symmetriesApr 19 2011We compute the charm drag and diffusion coefficients in a hot pion gas, such as is formed in a Heavy Ion Collision after the system cools sufficiently to transit into the hadron phase. We fully exploit Heavy Quark Effective Theory (with both D and D* ... More
Quantum gravitational contributions to the beta function of quantum electrodynamicsMar 30 2011We show in a diagrammatic and regularization independent analysis that the quadratic contribu- tion to the beta function which has been conjectured to render quantum electrodynamics asymp- totically free near the Planck scale has its origin in a surface ... More
Probing the infrared quark mass from highly excited baryonsFeb 20 2009Aug 04 2009We argue that three-quark excited states naturally group into quartets, split into two parity doublets, and that the mass splittings between these parity partners decrease higher up in the baryon spectrum. This decreasing mass difference can be used to ... More
One-step deposition and in-situ reduction of graphene oxide in glass microcapillaries and application to photonicsAug 23 2017Films of graphene oxide (GO) were produced on the inner walls of glass microcapillaries via insertion of a GO water suspension followed by quick drying with a hot finger (no previous surface functionalization required). Individual capillaries from an ... More
Using QCD Counting rules to Identify the Production of GluoniumOct 20 2018The empirical identification of bound states of gluons has remained a central goal of hadron spectroscopy. We suggest an experimentally challenging, but model--independent way to assess which zero charge, isospin-zero mesons have a large gluonium light-front ... More
Renormalization Scale-Fixing for Complex Scattering AmplitudesDec 20 2005Mar 16 2006We show how to fix the renormalization scale for hard-scattering exclusive processes such as deeply virtual meson electroproduction by applying the BLM prescription to the imaginary part of the scattering amplitude and employing a fixed-t dispersion relation ... More
How to identify gluonium states using QCD counting rulesDec 26 2018Verifying the existence of bound states of gluons and distinguishing them from conventional quark-antiquark, hybrid or tetraquark states has remained a key problem in QCD. We show that QCD counting rules for the power-law fall-off of production cross ... More
Bragg diffraction and the Iron crust of cold Neutron StarsMay 29 2009Jul 14 2011If cooled-down neutron stars have a thin atomic crystalline-iron crust, they must diffract X-rays of appropriate wavelength. If the diffracted beam is to be visible from Earth, the illuminating source must be very intense and near the reflecting star. ... More
Pion Gas ViscosityMay 14 2003We briefly report a calculation of the viscosity of a pion gas at finite temperature and chemical potential using three different models for the pion-pion interaction. The results for the Inverse Amplitude Method interpolation yield a viscosity of order ... More
Two infrared Yang-Mills solutions in stochastic quantization and in an effective action formalismJul 25 2012Sep 14 2012Three decades of work on the quantum field equations of pure Yang-Mills theory have distilled two families of solutions in Landau gauge. Both coincide for high (Euclidean) momentum with known perturbation theory, and both predict an infrared suppressed ... More
Cubic neutronsAug 09 2011The neutron is largely spherical and incompressible in atomic nuclei. These two properties are however challenged in the extreme pressure environment of a neutron star. Our variational computation within the Cornell model of Coulomb gauge QCD shows that ... More
Cubic wavefunction deformation of compressed atomsFeb 12 2015We hypothesize that in a non-metallic crystalline structure under extreme pressures, atomic wavefunctions deform to adopt a reduced rotational symmetry consistent with minimizing interstitial space in the crystal. We exemplify with a simple numeric variational ... More
Sparse mmWave OFDM Channel Estimation Using Compressed Sensing in OFDM SystemsDec 18 2018This paper proposes and analyzes a mmWave sparse channel estimation technique for OFDM systems that uses the Orthogonal Matching Pursuit (OMP) algorithm. This greedy algorithm retrieves one additional multipath component (MPC) per iteration until a stop ... More
Shannon entropy and particle decaysFeb 15 2018Apr 09 2018We deploy Shannon's information entropy to the distribution of branching fractions in a particle decay. This serves to quantify how important a given new reported decay channel is, from the point of view of the information that it adds to the already ... More
Mode transformation and frequency change with height in 3D numerical simulations of magneto-acoustic wave propagation in sunspotsMay 20 2010Three-dimensional numerical simulations of magnetoacoustic wave propagation are performed in a sunspot atmosphere with a computational domain covering from the photosphere to the chromosphere. The wave source, with properties resembling the solar spectrum, ... More
A Tuner that Accelerates ParametersMar 02 1999We propose a tuner, suitable for adaptive control and (in its discrete-time version) adaptive filtering applications, that sets the second derivative of the parameter estimates rather than the first derivative as is done in the overwhelming majority of ... More
Statistics of Q-Oscillators, Quons and Relation to Fractional SatisticsApr 23 1993The statistics of $q$-oscillators, quons and to some extent, of anyons are studied and the basic differences among these objects are pointed out. In particular, the statistical distributions for different bosonic and fermionic $q$-oscillators are found ... More
WASSA-2017 Shared Task on Emotion IntensityAug 11 2017We present the first shared task on detecting the intensity of emotion felt by the speaker of a tweet. We create the first datasets of tweets annotated for anger, fear, joy, and sadness intensities using a technique called best--worst scaling (BWS). We ... More
Shannon entropy and hadronic decaysOct 03 2017How much information is added to the Review of Particle Physics when a new decay branching ratio of a hadron is measured and reported? This is quantifiable by Shannon's information entropy $S(i) =-\sum_{f}BR_{(i\longrightarrow f)}\log BR_{(i\longrightarrow ... More
From Euclidean to Minkowski space with the Cauchy-Riemann equationsMay 27 2008Jun 25 2008We present an elementary method to obtain Green's functions in non-perturbative quantum field theory in Minkowski space from calculated Green's functions in Euclidean space. Since in non-perturbative field theory the analytical structure of amplitudes ... More
Relativistic Many-Body Hamiltonian Approach to MesonsJan 09 2001We represent QCD at the hadronic scale by means of an effective Hamiltonian, $H$, formulated in the Coulomb gauge. As in the Nambu-Jona-Lasinio model, chiral symmetry is explicity broken, however our approach is renormalizable and also includes confinement ... More
Improving Third-Party Relaying for LTE-A: A Realistic Simulation ApproachJan 20 2014In this article we propose solutions to diverse conflicts that result from the deployment of the (still immature) relay node (RN) technology in LTE-A networks. These conflicts and their possible solutions have been observed by implementing standard-compliant ... More
Exploiting non-trivial spatio-temporal correlations of thermal radiation for sunlight harvestingDec 17 2016The promise of any small improvement in the performance of light-harvesting devices, is sufficient to drive enormous experimental efforts. However these efforts are almost exclusively focused on enhancing the power conversion efficiency with specific ... More
On the Class of Possible Nonlocal Anyon-Like Operators and Quantum GroupsSep 22 1993We find a class of nonlocal operators constructed by attaching a disorder operator to fermionic degrees of freedom, which can be used to generate q-deformed algebras following the Schwinger approach. This class includes the recently proposed anyonic operators ... More
Diamagnetic field states in cosmological plasmasDec 22 2018Using a generally covariant Electro-Vortic (magnetofluid) formalism for relativistic plasmas, the dynamical evolution of a generalized vorticity (a combination of the magnetic and kinematic parts) is studied in a cosmological context. We derive macroscopic ... More
Coulomb Gauge Model for Exotic HadronsDec 28 2010Hadron structure advances provided by the Coulomb gauge model are summarized. Highlights include a realistic description of the vacuum and meson spectrum with chiral symmetry and dynamical flavor mixing, accurate hyperfine splittings for light and heavy ... More
The ratio of viscosity to entropy density in a pion gas satisfies the KSS holographic boundSep 25 2006Oct 30 2006We evaluate the ratio of shear viscosity to entropy density in a pion gas employing the Uehling-Uehlenbeck equation and experimental phase-shifts parameterized by means of the SU(2) Inverse Amplitude Method. We find that the ratio for this monocomponent ... More
Meson Structure in a Relativistic Many-Body ApproachJun 14 1999Results from an extensive relativistic many-body analysis utilizing a realistic effective QCD Hamiltonian are presented for the meson spectrum. A comparative numerical study of the BCS, TDA and RPA treatments provides new, significant insight into the ... More
Equivalence of the sine-Gordon and massive Thirring models at finite temperatureSep 04 1997Using the path-integral approach, the quantum massive Thirring and sine-Gordon models are proven to be equivalent at finite temperature. This result is an extension of Coleman's proof of the equivalence between both theories at zero temperature. The usual ... More
Chiral symmetry breaking for fermions charged under large Lie groupsAug 15 2018We reexamine the dynamical generation of mass for fermions charged under various Lie groups with equal charge and mass at a high Grand Unification scale, extending the Renormalization Group Equations in the perturbative regime to two-loops and matching ... More
Pictures of Blockscale Transport: Effective versus Ensemble Dispersion and Its UncertaintyNov 25 2016Using a Lagrangian framework, we discuss different conceptualizations of the blockscale dispersion tensor. We distinguish effective and ensemble blockscale dispersion, which measure the impact of subscale velocity fluctuations on solute dispersion. Ensemble ... More
Soft interactions in jet quenchingSep 27 2013Nov 05 2014We study the collisional aspects of jet quenching in a high energy nuclear collision, especially in the final state pion gas. The jet has a large energy, and acquires momentum transverse to its axis more effectively by multiple soft collisions than by ... More
Radiation reaction on a classical charged particle: a modified form of the equation of motionNov 23 2012Sep 24 2013We present and numerically solve a modified form of the equation of motion for a charged particle under the influence of an external force, taking into account the radiation reaction. This covariant equation is integrodifferential, as Dirac-R\"ohrlich's, ... More
Left lane road electrificationNov 01 2010Oct 29 2012We propose the left-side electrification of multilane motorways in suburban areas as a practical way of implementing on-road charging in order to reduce the weight and price of electrically-powered automobiles. These could then be supplied energy en-route, ... More
On the violation of the holographic viscosity versus entropy KSS bound in non relativistic systemsMar 14 2007May 16 2007A computation of the quotient of shear viscosity to entropy density, or KSS number $\eta/s$ is performed, in the non-relativistic and classical regime, first in Chiral Perturbation Theory, and then in the $SO(g+1)/SO(g)$ Non-Linear Sigma Model in the ... More
Many-Body Approach to Mesons, Hybrids and GlueballsSep 15 2000We represent QCD at the hadronic scale by means of an effective Hamiltonian, H, formulated in the Coulomb gauge. As in the Nambu-Jona-Lasinio model, chiral symmetry is dynamically broken, however our approach is renormalizable and also includes confinement ... More
The Viscosity of Meson MatterSep 29 2003We report a calculation of the shear viscosity in a relativistic multicomponent meson gas as a function of temperature and chemical potentials. We approximately solve the Uehling-Uhlenbeck transport equation of kinetic theory, appropriate for a boson ... More
Many-Body Coulomb Gauge Exotic and Charmed HybridsAug 31 2000Oct 25 2000Utilizing a QCD Coulomb gauge Hamiltonian with linear confinement specified by lattice, we report a relativistic many-body calculation for the light exotic and charmed hybrid mesons. The Hamiltonian successfully describes both quark and gluon sectors, ... More
Observational signatures of numerically simulated MHD waves in small-scale fluxtubesJan 25 2008We present some results obtained from the synthesis of Stokes profiles in small-scale flux tubes with propagating MHD waves. To that aim, realistic flux tubes showing internal structure have been excited with 5 min period drivers, allowing non-linear ... More
Magnetic field generation in curved spacetimesMar 23 2011Oct 08 2012Using the generally covariant magnetofluid formalism for a hot plasma, a new curvature (of space time) driven mechanism for generating seed vorticity/magnetic field is presented. The "battery" owes its origin to the interaction between gravity (epitomized ... More
Magneto-acoustic wave energy from numerical simulations of an observed sunspot umbraApr 20 2011We aim at reproducing the height dependence of sunspot wave signatures obtained from spectropolarimetric observations through 3D MHD numerical simulations. A magneto-static sunspot model based on the properties of the observed sunspot is constructed and ... More
On the analysis of signals in a permutation Lempel-Ziv complexity - permutation Shannon entropy planeJul 17 2017The aim of this paper is to introduce the Lempel-Ziv permutation complexity vs permutation entropy plane as a tool to analyze time series of different nature. This two quantities make use of the Bandt and Pompe representation to quantify continuous-state ... More
RPA Vector Meson Leptonic WidthsAug 13 2004Recent J = 0 (para) baryonium interpretations of the BES narrow resonance data near the e^-e^+ -> p anti-p threshold suggests the existance of ortho baryonium. To assist future searches we study J = 1 states, especially vector meson leptonic decays, and ... More
Relativistic Quark Model Calculation of the l1, l2 Coefficients of the Chiral LagrangianDec 13 2002We briefly report on a relativistic quark model scheme to calculate the O(P^4) pion-pion vertex in the planar approximation and in the chiral limit. The calculation is reduced to the solution of simple integral equations (Bethe-Salpeter like) by an effective ... More
Magneto-acoustic waves in sunspots: first results from a new 3D nonlinear magnetohydrodynamic codeJun 15 2010Waves observed in the photosphere and chromosphere of sunspots show complex dynamics and spatial patterns. The interpretation of high-resolution sunspot wave observations requires modeling of three-dimensional non-linear wave propagation and mode transformation ... More
Natural inflation in 5D warped backgroundsOct 31 2007Jul 13 2008In light of the five-year data from the Wilkinson Microwave Anisotropy Probe (WMAP), we discuss models of inflation based on the pseudo Nambu-Goldstone potential predicted in five-dimensional gauge theories for different backgrounds: flat Minkowski, anti-de ... More
Identifying Higher-order Combinations of Binary FeaturesJul 04 2014Finding statistically significant interactions between binary variables is computationally and statistically challenging in high-dimensional settings, due to the combinatorial explosion in the number of hypotheses. Terada et al. recently showed how to ... More
Emotion Intensities in TweetsAug 11 2017This paper examines the task of detecting intensity of emotion from text. We create the first datasets of tweets annotated for anger, fear, joy, and sadness intensities. We use a technique called best--worst scaling (BWS) that improves annotation consistency ... More
Coulomb Gauge QCD and the Excited Hadron SpectrumDec 28 2010We discuss progress in understanding the light and heavy quark excited hadron spectrum from Coulomb gauge QCD. For light quark systems we highlight the insensitivity to spontaneous chiral symmetry breaking, which predicts Wigner parity-degeneracy in the ... More
The variation of the electromagnetic coupling and quintessenceDec 28 2008The properties of quintessence are examined through the study of the variation of the electromagnetic coupling. We consider two simple quintessence models with a modified exponential potential and study the parameter space constraints derived from the ... More
Non-linear numerical simulations of magneto-acoustic wave propagation in small-scale flux tubesOct 17 2007Jan 25 2008We present results of non-linear, 2D, numerical simulations of magneto-acoustic wave propagation in the photosphere and chromosphere of small-scale flux tubes with internal structure. Waves with realistic periods of three to five minutes are studied, ... More
q-Supersymmetric Generalization of von Neumann's TheoremMay 21 1993Assuming that there exist operators which form an irreducible representation of the q-superoscillator algebra, it is proved that any two such representations are equivalent, related by a uniquely determined superunitary transformation. This provides with ... More
Hot Fluids and Nonlinear Quantum MechanicsMay 17 2013It is shown that a hot relativistic fluid could be viewed as a collection of self-interacting quantum objects. They obey a nonlinear equation which is a modification of the quantum equation obeyed by elementary constituents of the fluid. A uniform phenomenological ... More
Vortical Dynamics of spinning quantum plasmas - Helicity ConservationOct 17 2011It is shown that a vorticity, constructed from spin field of a quantum spinning plasma, combines with the classical generalized vorticity (representing the magnetic and the velocity fields) to yield a new grand generalized vorticity that obeys the standard ... More
Hadron physics potential of future high-luminosity B-factories at the Upsilon(5S) and aboveOct 24 2012Jan 15 2013We point out the physics opportunities of future high-luminosity B-factories at the Upsilon(5S) resonance and above. In this paper we discuss numerous interesting investigations, which can be performed in the e+e- centre-of-mass energy region from the ... More
Local Two-Photon Couplings and the J=0 Fixed Pole in Real and Virtual Compton ScatteringDec 02 2008The local coupling of two photons to the fundamental quark currents of a hadron gives an energy-independent contribution to the Compton amplitude proportional to the charge squared of the struck quark, a contribution which has no analog in hadron scattering ... More
Gravitational baryogenesis in Gauss-Bonnet braneworld cosmologyApr 14 2005Jun 07 2005The mechanism of gravitational baryogenesis, based on the CPT-violating gravitational interaction between the derivative of the Ricci scalar curvature and the baryon-number current, is investigated in the context of the Gauss-Bonnet braneworld cosmology. ... More
Sneutrino brane inflation and leptogenesisFeb 26 2004Apr 02 2004Modifications to the Friedmann equation in brane cosmology can have important implications for early universe phenomena such as inflation and the generation of the baryon asymmetry. We study a simple scenario of chaotic brane inflation where, in a minimal ... More
Gemini-South + FLAMINGOS Demonstration Science: Near-Infrared Spectroscopy of the z=5.77 Quasar SDSS J083643.85+005453.3Sep 16 2003We report an infrared 1-1.8 micron (J+H-bands), low-resolution (R=450) spectrogram of the highest-redshift radio-loud quasar currently known, SDSS J083643.85+005453.3, obtained during the spectroscopic commissioning run of the FLAMINGOS multi-object, ... More