Results for "S. Uttiya"

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3D printing of optical materials: an investigation of the microscopic propertiesJul 09 20183D printing technologies are currently enabling the fabrication of objects with complex architectures and tailored properties. In such framework, the production of 3D optical structures, which are typically based on optical transparent matrices, optionally ... More
3D photo-responsive optical devices manufactured by advanced printing technologiesApr 12 2019Photonic components responsive to external optical stimuli are attracting increasing interest, because their properties can be manipulated by light with fast switching times, high spatial definition, and potentially remote control. These aspects can be ... More
Ultralow friction of ink-jet printed graphene flakesMay 03 2018We report the frictional response of few-layer graphene (FLG) flakes obtained by liquid phase exfoliation (LPE) of pristine graphite. To this end, we inkjet print FLG on bare and hexamethyldisilazane-terminated SiO2 substrates, producing micrometric patterns ... More
Band insulator to Mott insulator transition in a bilayer Hubbard modelMar 27 2007The ground state phase diagram of the half-filled repulsive Hubbard model in a bilayer is investigated using cluster dynamical mean field theory. For weak to intermediate values of Coulomb repulsion $U$, the system undergoes a transition from a Mott insulating ... More
Band dispersion and electronic lifetimes in crystalline organic semiconductorsJan 11 2011Mar 31 2011The consequences of several microscopic interactions on the photoemission spectra of crystalline organic semiconductors (OSC) are studied theoretically. It is argued that their relative roles can be disentangled by analyzing both their temperature and ... More
Band-like motion and mobility saturation in organic molecular semiconductorsOct 22 2009Dec 07 2009We analyze a model that accounts for the inherently large thermal lattice fluctuations associated to the weak van der Waals inter-molecular bonding in crystalline organic semiconductors. In these materials the charge mobility generally exhibits a "metallic-like" ... More
Optical properties of small polarons from dynamical mean-field theoryDec 09 2005Feb 27 2006The optical properties of polarons are studied in the framework of the Holstein model by applying the dynamical mean-field theory. This approach allows to enlighten important quantitative and qualitative deviations from the limiting treatments of small ... More
Hopping dynamics of interacting polaronsOct 02 2008We derive an effective cluster model to address the transport properties of mutually interacting small polarons. We propose a decoupling scheme where the hopping dynamics of any given particle is determined by separating out explicitly the degrees of ... More
On the Ascoli property for locally convex spaces and topological groupsNov 09 2016Nov 14 2016We characterize Ascoli spaces by showing that a Tychonoff space $X$ is Ascoli iff the canonical map from the free locally convex space $L(X)$ over $X$ into $C_k\big( C_k(X)\big)$ is an embedding of locally convex spaces. We prove that an uncountable direct ... More
Metric-affine $f(R)$-gravity with torsion: an overviewOct 27 2009Torsion and curvature could play a fundamental role in explaining cosmological dynamics. f(R)-gravity with torsion is an approach aimed to encompass in a comprehensive scheme all the Dark Side of the Universe (Dark Energy and Dark Matter). We discuss ... More
Groups of quasi-invariance and the Pontryagin dualityDec 09 2008Oct 01 2009A Polish group $G$ is called a group of quasi-invariance or a QI-group, if there exist a locally compact group $X$ and a probability measure $\mu$ on $X$ such that 1) there exists a continuous monomorphism of $G$ to $X$, and 2) for each $g\in X$ either ... More
The Higgs Boson Production Cross Section as a Precision Observable?Mar 06 2002Jul 30 2002We investigate what can be learned at a linear collider about the sector of electroweak symmetry breaking from a precise measurement of the Higgs boson production cross section through the process e+e- -> hZ. We focus on deviations from the Standard Model ... More
X-ray observations of cluster outskirts: current status and future prospectsMay 03 2010Dec 22 2010Past and current X-ray mission allow us to observe only a fraction of the volume occupied by the ICM. After reviewing the state of the art of cluster outskirts observations we discuss some important constraints that should be met when designing an experiment ... More
Lower and upper bounds on the mass of light quark-antiquark scalar resonance in the SVZ sum rulesMay 23 2016The calculation of the mass of light scalar isosinglet meson within the Shifman--Vainshtein--Zakharov (SVZ) sum rules is revisited. We develop simple analytical methods for estimation of hadron masses in the SVZ approach and try to reveal the origin of ... More
Low-energy holographic models for QCDFeb 01 2011Apr 09 2011We consider the bottom-up holographic models for QCD which contain the ultraviolet (UV) cutoff. Such models are supposed to describe exclusively the low-energy sector of QCD. The introduction of UV cutoff in the soft wall model is shown to result in a ... More
AdS/QCD models describing a finite number of excited mesons with Regge spectrumMar 02 2009The typical AdS/QCD models deal with the large-N_c limit of QCD, as a consequence the meson spectrum consists of the infinite number of states that is far from the real situation. Basing on introduction of anharmonic corrections to the holographic potential, ... More
Generalized Soft Wall ModelOct 18 2012Jan 27 2013We develop an exactly solvable generalization of the soft wall holographic model for the vector mesons. The generalization preserves the ultraviolet and infrared asymptotics of the soft wall model and contains an additional free parameter. This new parameter ... More
Comment on "Parity Doubling and SU(2)_L X SU(2)_R Restoration in the Hadronic Spectrum" and "Parity Doubling Among the Baryons"May 09 2006Some aspects of two recent papers on parity doubling in the hadronic spectrum and its relation to restoration of linearly realized chiral symmetry are critically discussed.
Steenrod operations and the diagonal morphismJul 04 2013Jan 15 2014We show how to find the Steenrod operations in H^*(X) (the coefficients in F_p) given the diagonal morphism d_#:S_*(X)->S_*(X^p) and the action of the cyclic group C_p on S_*(X^p). Our construction needs no other data such as Eilenberg-Zilber morphisms. ... More
The Game of Cipher BeadsMay 20 2009Jul 29 2009Comparison between the various impact factors of a few Russian journals demonstrates the deficiencies of the popular citation indices.
On Grothendieck SubspacesApr 04 2005The modulus of an order bounded functional on a Riesz space is the sum of a pair of Riesz homomorphisms if and only if the kernel of this functional is a Grothendieck subspace of the ambient Riesz space. An operator version of this fact is given.
Generalized Integral Siding Mode Manifold Design: A Sum of Squares ApproachMar 30 2015May 21 2015This paper presents a general form of integral sliding mode manifold, and proposes an algorithmic approach based on Sum of Squares (SOS) programming to design generalized integral sliding mode manifold and controller for nonlinear systems with both matched ... More
Effective Use of Human Computer Interaction in Digital Academic Supportive DevicesJan 03 2015In this research, a literature in human-computer interaction is reviewed and the technology aspect of human computer interaction related with digital academic supportive devices is also analyzed. According to all these concerns, recommendations to design ... More
Influence of Facebook in Academic Performance of Sri Lankan University StudentsJan 03 2015Facebook is only an electronic communication between human but unfortunately it has become an addiction for all. This paper examines the usage of Facebook among university students and its influence in their academic performance. The impact of Facebook ... More
Di-photon Higgs signals at the LHC in the Next-to-Minimal Supersymmetric Standard ModelMar 10 2006The NMSSM contains a Higgs singlet in addition to the two Higgs doublets typical of the MSSM, thus resulting in a total of seven physical Higgs mass states. Therefore, the phenomenology of the NMSSM Higgs sector can vary considerably from that of the ... More
Shock Dissipation in Magnetically Dominated Impulsive FlowsJan 17 2012We have revisited the issue of shock dissipation and emission and its implications for the internal shock model of the prompt GRB emission and studied it in the context of impulsive Poynting-dominated flows. Our results show that unless the magnetization ... More
3+1 MagnetodynamicsAug 17 2011Aug 30 2011The Magnetodynamics, or Force-Free Degenerate Electrodynamics, is recognized as a very useful approximation in studies of magnetospheres of relativistic stars. In this paper we discuss various forms of Magnetodynamic equations which can be used to study ... More
Blandford-Znajek mechanism versus Penrose processApr 11 2008During the three decades since its theoretical discovery the Blandford-Znajek process of extracting the rotational energy of black holes has become one of the foundation stones in the building of modern relativistic astrophysics. However, it is also true ... More
Multi-dimensional Numerical Scheme for Resistive Relativistic MHDAug 02 2007The paper describes a new upwind conservative numerical scheme for special relativistic resistive magnetohydrodynamics with scalar resistivity. The magnetic field is kept approximately divergence free and the divergence of the electric field consistent ... More
Geometry of N=4, d=1 nonlinear supermultipletNov 09 2006We construct the general action for $N=4, d=1$ nonlinear supermultiplet including the most general interaction terms which depend on the arbitrary function $h$ obeying the Laplace equation on $S^3$. We find the bosonic field $B$ which depends on the components ... More
Random walks in a random environmentMar 05 2005Random walks as well as diffusions in random media are considered. Methods are developed that allow one to establish large deviation results for both the `quenched' and the `averaged' case.
Heavy charged Higgs boson production at next generation $γγ$ collidersNov 05 2002We investigate the scope of all relevant production modes of charged Higgs bosons in the MSSM, with mass larger than the one of the top quark, at future Linear Colliders operating in $\gamma\gamma$ mode at the TeV energy scale. Final states with one or ... More
Electron-hole asymmetry in magnetic properties of lightly doped high-$T_{\rm C}$ superconductors: a quantum Monte Carlo studyAug 14 2003Using a recently developed variational quantum Monte Carlo method, magnetic properties of high-$T_{\rm C}$ superconductors are studied at zero temperature ($T$), by numerical simulations on the 2D t-J model. Our focus here is to explore the difference ... More
Reducing Polarization Mode Dispersion With Controlled Polarization RotationsJun 02 2006One of the fundamental limitations to high bit rate, long distance, telecommunication in optical fibers is Polarization Mode Dispersion (PMD). Here we introduce a conceptually new method to reduce PMD in optical fibers by carrying out controlled rotations ... More
Superconducting networks with the proximity effectNov 06 2009May 20 2011We report on the first observation of a novel type of superconducting proximity network using a superconductor-normal metal bilayer. Little-Parks oscillation measurements show that the superconducting current flows through a path enclosed by the edge ... More
An Observational Perspective of the IMF: Progress and ChallengesOct 20 2015The stellar initial mass function (IMF) is a fundamental astrophysical quantity that impacts a wide range of astrophysical problems from heavy element distribution to galactic evolution to planetary system formation. However, the origin and universality ... More
The mass function of young star clusters in spiral galaxiesDec 07 2008Sep 23 2009The initial cluster mass function (ICMF) in spiral galaxy discs is constrained and compared with data for old globular clusters and young clusters in starbursts. It is found that the observed ages and luminosities of the brightest clusters in spiral discs ... More
Observational Constraints on Cluster EvolutionSep 04 2006Current observational constraints on the dynamical evolution of star clusters are reviewed. Theory and observations now agree nicely on the mass dependency and time scales for disruption of young star clusters in galactic disks, but many problems still ... More
Zero-Range Potentials in Multi-Channel Diatomic Molecule ScatteringMay 17 2002The method of zero-range potentials is generalized to account for the molecular electron excitation process. It is made by a matrix formulation in which a state vector components are associated with a scattering channel. The multi-center target is considered ... More
Finite-size effects on the Hamiltonian dynamics of the XY-modelMay 31 2001The dynamical properties of the finite-size magnetization M in the critical region T<T_{KTB} of the planar rotor model on a L x L square lattice are analyzed by means of microcanonical simulations . The behavior of the q=0 structure factor at high frequencies ... More
Light-front $φ^4_{1+1}$ theory using a many-boson symmetric-polynomial basisDec 29 2015We extend earlier work on fully symmetric polynomials for three-boson wave functions to arbitrarily many bosons and apply these to a light-front analysis of the low-mass eigenstates of $\phi^4$ theory in 1+1 dimensions. The basis-function approach allows ... More
Application of a light-front coupled-cluster method to quantum electrodynamicsJun 26 2012A field-theoretic formulation of the exponential-operator technique is applied to a Hamiltonian eigenvalue problem in electrodynamics, quantized in light-front coordinates. Specifically, we consider the dressed-electron state, without positron contributions ... More
Magnetization induced by odd-frequency spin-triplet Cooper pairs in a Josephson junction with metallic trilayersJul 14 2015We theoretically study the magnetization inside a normal metal induced in an s-wave superconductor/ferromagnetic metal/normal metal/ferromagnetic metal/s-wave superconductor (S/F1/N/F2/S) Josephson junction. Using quasiclassical Green's function method, ... More
Relativistic Toda chain at root of unityJan 15 2001May 17 2001We declare briefly several interesting features of the quantum relativistic Toda chain at N-th root of unity. We consider the finite dimensional representation of the Weyl algebra. The origin of the features mentioned is that we consider simultaneously ... More
Spin Injection and Detection in Magnetic NanostructuresDec 13 2002We study theoretically the spin transport in a nonmagnetic metal connected to ferromagnetic injector and detector electrodes. We derive a general expression for the spin accumulation signal which covers from the metallic to the tunneling regime. This ... More
DENIS Survey Data Probing Different Types of PNeFeb 06 2002We present near-infrared photometry of a large sample of planetary nebulae (PNe) and show that the IJK colours are a good tool to distinguish different classes of PNe, like nebulae around symbiotic Miras or IR-[WC] PNe from genuine PNe.
Black Holes and Naked Singularities in Low Energy Limit of String Gravity with Modulus FieldSep 11 2000Mar 16 2001We show that the black hole solutions of the effective string theory action, where one-loop effects that couple the moduli to gravity via a Gauss-Bonnet term are taken into account, admit primary scalar hair. The requirement of absence of naked singularities ... More
Threshold Based Indexing of Commercial Shoe Print to Create Reference and Recovery ImagesJan 29 2010One of the important evidence in a crime scene that is normally overlooked but very important evidence is shoe print as the criminal is normally unaware of the mask for this. In this paper we use image processing technique to process reference shoe images ... More
From transient localization to band transport: on quantum corrections and lack thereofMar 29 2019Transient localization has emerged as a powerful theoretical framework that is able to describe charge transport in high-mobility organic semiconductors, where the carrier diffusion is strongly limited by their coupling to thermal molecular motions. As ... More
A first-principles systematic study of GaAs nanowiresJan 22 2009Dec 23 2010In this paper we present a detailed analysis of the atomic and electronic structure of GaAs nanowires using first-principles pseudopotential calculations. We consider six different types of nanowires with different diameters all grown along [111] direction ... More
The $B-L$ Supersymmetric Standard Model with Inverse Seesaw at the Large Hadron ColliderMar 27 2015Dec 06 2016We review the TeV scale $B-L$ extension of the Minimal Supersymmetric Standard Model (BLSSM) where an inverse seesaw mechanism of light neutrino mass generation is naturally implemented and concentrate on its hallmark manifestations at the Large Hadron ... More
Quantisation of twistor theory by cocycle twistJan 30 2007Mar 20 2007We present the main ingredients of twistor theory leading up to and including the Penrose-Ward transform in a coordinate algebra form which we can then `quantise' by means of a functorial cocycle twist. The quantum algebras for the conformal group, twistor ... More
Expected Number of Local Maxima of Some Gaussian Random PolynomialsMay 04 2006Let $Q_n(x)=\sum_{i=0}^{n} A_{i}x^{i}$ be a random algebraic polynomial where the coefficients $A_0,A_1,... $ form a sequence of centered Gaussian random variables. Moreover, assume that the increments $\Delta_j=A_j-A_{j-1}$, $j=0,1,2,...$ are independent, ... More
On the possibility of Casimir repulsion using MetamaterialsSep 15 2009It is well known that the Casimir force between two half-spaces is dictated by their electromagnetic properties. In particular, when one of the half-spaces is mainly metallic or dielectric and the other is mainly magnetic, it is possible to show that ... More
Growth kinetic study of sputter deposition: Ag on Si/SiO$_2$Sep 11 2001Nov 30 2001We have presented the kinetic study of the very initial growth stages of an ultra thin film (40 $\AA$- 150$\AA$) of Ag sputter-deposited on Si(001) substrate containing native oxide using grazing incidence x-ray reflectivity (GIXR) technique and Atomic ... More
Effect of Diorder on the Peak Effect and Structure of Flux Line Lattice in 2H-NbSe2Sep 16 1997The effect of disorder on flux line lattice (FLL) melting is studied via the Peak Effect phenomenon. On the upper branch of the Peak Effect curve, where this effect is more robust, we observe a stepwise disordering of the FLL, suggesting two first order ... More
Infrared absorption in a quantum wire in the presence of spin-orbit coupling: a technique to measure different types of spin-orbit interaction strengthsAug 26 2005Mar 19 2006We show that the dominant absorption peak due to inter-subband transition in a gated quantum wire, with two occupied subbands, will split into a main peak and two satellite peaks if both Rashba and Dresselhaus spin-orbit interactions are present. One ... More
Controlling quantum random walk with a step-dependent coinMar 02 2018Aug 22 2018We report on the possibility of controlling quantum random walks with a step-dependent coin. The coin is characterized by a (single) rotation angle. Considering different rotation angles, one can find diverse probability distributions for this walk including: ... More
Review and Analysis of The Issues of Unified Modeling Language for Visualizing, Specifying, Constructing and Documenting the Artifacts of a Software-Intensive SystemJan 23 2010The UML allows us to specify models in a precise, complete and unambiguous manner. In particular, the UML addresses the specification of all important decisions regarding analysis, design and implementation. Although UML is not a visual programming language, ... More
Estimation of Effort in Software Cost Analysis for Heterogenous Dataset using Fuzzy AnalogyNov 06 2012One of the significant objectives of software engineering community is to use effective and useful models for precise calculation of effort in software cost estimation. The existing techniques cannot handle the dataset having categorical variables efficiently ... More
EDM constraints and CP asymmetries of B processes in supersymmetric modelsDec 22 2004We demonstrate that electric dipole moments (EDMs) strongly constrain possible SUSY contributions to the CP asymmetries of B processes; LL and/or RR flavour mixings between second and third generations are severely restricted by the experimental limit ... More
Event-Driven Molecular Dynamics in ParallelFeb 03 2003Sep 16 2003Although event-driven algorithms have been shown to be far more efficient than time-driven methods such as conventional molecular dynamics, they have not become as popular. The main obstacle seems to be the difficulty of parallelizing event-driven molecular ... More
Ito diffusions, modified capacity and harmonic measure. Applications to Schrodinger operatorsDec 17 2010Using certain Ito's equation, we introduce the probability on the space of paths and show its relevance to the scattering properties of multidimensional Schrodinger operator. To relate the geometry of the support of potential to the spectral type we develop ... More
Oscillating structure of γ-bursts and their possible originMay 04 2000As it is well-known that the hydrodinamic collapse of the massive star iron core should lead to the production of a hot neutron star. The assumption is made that the thermonuclear burning of the envelope matter, accreting onto the hot neutron star, can ... More
Derivative-based global sensitivity measures and their link with Sobol sensitivity indicesMay 25 2016The variance-based method of Sobol sensitivity indices is very popular among practitioners due to its efficiency and easiness of interpretation. However, for high-dimensional models the direct application of this method can be very time consuming and ... More
Abelian Cascade Dynamics in Bootstrap PercolationJul 27 1998The culling process in Bootstrap Percolation is Abelian since the final stable configuration does not depend on the details of the updating procedure. An efficient algorithm is devised using this idea for the determination of the bootstrap percolation ... More
Sobolev and Schwartz: Two Fates and Two FamesFeb 05 2008Feb 13 2008This is a brief overview of the lives and contributions of S.L. Sobolev and L. Schwartz, the cofounders of distribution theory.
The eta-photon transition form factorOct 28 2011Feb 08 2012The eta-photon transition form factor is evaluated in a formalism based on a phenomenological description at low values of the photon virtuality, and a QCD-based description at high photon virtualities, matching at a scale $Q_{0}^{2}$. The high photon ... More
On topological properties of the group of the null sequences valued in an Abelian topological groupJun 21 2013Dec 09 2013Following [23], denote by $\mathfrak{F}_0$ the functor on the category $\mathbf{TAG}$ of all Hausdorff Abelian topological groups and continuous homomorphisms which passes each $X\in \mathbf{TAG}$ to the group of all $X$-valued null sequences endowed ... More
Semiclassical limit for nonlinear Schroedinger equations with electromagnetic fieldsJul 06 2001Aug 21 2002We prove some multiplicity results by means of a perturbation technique in critical point theory.
Boolean Models and Simultaneous InequalitiesJul 01 2009Aug 27 2009Boolean models are applied to deriving operator versions of the classical Farkas Lemma in the theory of simultaneous linear inequalities.
Pareto Optimality and IsoperimetryFeb 06 2009Under study is the new class of geometrical extremal problems in which it is required to achieve the best result in the presence of conflicting goals; e.g., given the surface area of a convex body $\mathfrak x$, we try to maximize the volume of $\mathfrak ... More
Bouvier's conjectureNov 28 2008This paper deals with Bouvier's conjecture which sustains that finite-dimensional non-Noetherian Krull domains need not be Jaffard
Modelling the VHE flare of 3C 279 using one zone leptonic modelSep 12 2011We model the simultaneous observations of the flat spectrum radio quasar 3C 279 at radio, optical, X-ray and very high energy (VHE) gamma ray energies during 2006 flare using a simple one zone leptonic model. We consider synchrotron emission due to cooling ... More
The Cauchy problem for metric-affine f(R)-gravity in presence of a Klein-Gordon scalar fieldMar 22 2010We study the initial value formulation of metric-affine f(R)-gravity in presence of a Klein-Gordon scalar field acting as source of the field equations. Sufficient conditions for the well-posedness of the Cauchy problem are formulated. This result completes ... More
Low metallicity AGB models: H profile in the 13C-pocket and the effect on the s-processMay 17 2010The 13C(a, n)16O reaction is the major neutron source in low mass asymptotic giant branch (AGB) stars, where the main and the strong s process components are synthesised. After a third dredge-up (TDU) episode, 13C burns radiatively in a thin pocket which ... More
Resonating valence bond wave function for the two dimensional fractional spin liquidAug 13 2003Feb 19 2004The unconventional low-lying spin excitations, recently observed in neutron scattering experiments on ${\rm Cs_2 Cu Cl_4}$, are explained with a spin liquid wave function. The dispersion relation as well as the wave vector of the incommensurate spin correlations ... More
Enhanced signal propagation in a network with unidirectional and random couplingsApr 22 2014We investigate the effect of unidirectional regular and random couplings of units in a network on stochastic resonance. For simplicity we choose the units as Bellows map with bistability. In a regular network we apply a weak periodic signal and noise ... More
On the Ascoli property for locally convex spaces and topological groupsNov 09 2016We characterize Ascoli spaces by showing that a Tychonoff space $X$ is Ascoli iff the canonical map from the free locally convex space $L(X)$ over $X$ into $C_k\big( C_k(X)\big)$ is an embedding of locally convex spaces. We prove that an uncountable direct ... More
Quotient Equations and Integrals of Motion for Massive Spinor FieldMar 29 2003In this article a group-theoretical aspect of the method of dimensional reduction is presented. Then, on the base of symmetry analysis of an anisotropic space geometrical description of dimensional reduction of equation for massive spinor field is given. ... More
Soft wall model with inverse exponential profile as a model for the axial and pseudoscalar mesonsJul 11 2012According to the conjecture of the gauge/gravity duality a strongly coupled 4D field theory may be described by a dual 5D theory which is a free field theory in the first approximation. The usual description of the axial-vector sector in the bottom-up ... More
No-Wall Holographic Model for QCDDec 22 2010Mar 03 2011We propose a new type of bottom-up holographic model describing the Regge like spectrum of mesons. This type of spectrum emerges due to condensation of a scalar field in the bulk anti-de Sitter space. The gauge invariance of the action describing the ... More
Holographic like models as a five-dimensional rewriting of large-Nc QCDJan 18 2010Oct 13 2010The AdS/QCD models are known to be tightly related with the QCD sum rules in the large-Nc (called also planar) limit. Rewriting the theory of infinite tower of free stable mesons expected in the large-Nc QCD as a five-dimensional theory we scrutinize ... More
About the possibility of five-dimensional effective theories for low-energy QCDMar 18 2009The AdS/QCD models suggest an interesting idea that the effective theory of low-energy QCD may be formulated as a 5-dimensional field theory in the weak coupling regime in which the fifth coordinate plays a role of inverse energy scale. Taking the point ... More
A five-dimensional toy-model for light hadron excitationsAug 04 2009Jun 17 2010In the usual holographic approach to QCD, the meson spectrum is generated due to a non-trivial 5-dimensional background. We propose an alternative 5-dimensional scenario in which the spectrum emerges due to coupling to a scalar field whose condensation ... More
Properties of new unflavored mesons below 2.4 GeVJul 05 2007The global features of spectrum of highly excited light nonstrange mesons can be well understood within both chiral symmetry restoration scenario combined with the relation $M^2\sim J+n$ and within nonrelativistic description based on the relation $M^2\sim ... More
Saunders Mac Lane, the Knight of MathematicsJul 11 2005This is a short obituary of Saunders Mac Lane (1909--2005).
Energy flows in vibrated granular mediaMay 20 1998We study vibrated granular media, investigating each of the three components of the energy flow: particle-particle dissipation, energy input at the vibrating wall, and particle-wall dissipation. Energy dissipated by interparticle collisions is well estimated ... More
Energy non-equipartition in systems of inelastic, rough spheresMay 20 1998We calculate and verify with simulations the ratio between the average translational and rotational energies of systems with rough, inelastic particles, either forced or freely cooling. The ratio shows non-equipartition of energy. In stationary flows, ... More
Nucleon participants or quark participants?Feb 24 2003May 07 2003We show that centrality dependence of charged particle pseudorapidity density at midrapidity in Au+Au collisions at RHIC is well described as proportional to We show that centrality dependence of charged particle pseudorapidity density at midrapidity ... More
BPS Saturated String Amplitudes: K3 Elliptic Genus and Igusa Cusp FormAug 01 2011Nov 15 2011We study BPS saturated one-loop amplitudes in type II string theory compactified on K3 x T^2. The classes of amplitudes we consider are only sensitive to the very basic topological data of the internal K3 manifold. As a consequence, the integrands of ... More
Uses of Linear Polarization as a Probe of Extrasolar Planet AtmospheresMay 22 2003We point out some advantages of making observations of extrasolar planets in linearly polarized (LP) light. Older cool stars have quite low levels (~ 10^-4 to 10^-5) of fractional LP, while extrasolar planets can have relatively high fractional LP (~0.1). ... More
CP-violation in K_{S,L}->π^{+}π^{-}γand K_{S,L}->π^{+}π^{-}e^{+}e^{-} decaysSep 04 2001Apr 27 2002The dependence of K_{S,L}->\pi^{+}\pi^{-}\gamma decay probabilities on photon polarization is calculated. The phases of terms of amplitude that arise from the pion-pion interaction are obtained by using a simple realistic model of pion-pion interaction ... More
Caldirola-Kanai Oscillator in Classical Formulation of Quantum MechanicsFeb 23 1998The quadrature distribution for the quantum damped oscillator is introduced in the framework of the formulation of quantum mechanics based on the tomography scheme. The probability distribution for the coherent and Fock states of the damped oscillator ... More
Magnetic dissipation in the Crab NebulaJul 13 2012Oct 15 2012Magnetic dissipation is frequently invoked as a way of powering the observed emission of relativistic flows in Gamma Ray Bursts and Active Galactic Nuclei. Pulsar Wind Nebulae provide closer to home cosmic laboratories which can be used to test the hypothesis. ... More
Magnetic acceleration of relativistic jetsJun 11 2010This is a brief review of the recent developments in the theory of magnetic acceleration of relativistic jets. We attempt to explain the key results of this complex theory using basic physical arguments and simple calculations. The main focus is on the ... More
Magnetized Tori around Kerr Black Holes: Analytic Solutions with a Toroidal Magnetic FieldJan 30 2006Mar 01 2006The dynamics of accretion discs around galactic and extragalactic black holes may be influenced by their magnetic field. In this paper we generalise the fully relativistic theory of stationary axisymmetric tori in Kerr metric of Abramowicz et al.(1978) ... More
On the Properties of Time-Dependent, Force-Free, Degenerate ElectrodynamicsFeb 25 2002This paper formulates time-dependent, force-free, degenerate electrodynamics as a hyperbolic system of conservation laws. It is shown that this system has four characteristic modes, a pair of fast waves propagating with the speed of light and a pair of ... More
Observations of the Blandford-Znajek and the MHD Penrose processes in computer simulations of black hole magnetospheresJan 27 2005In this paper we report the results of axisymmetric relativistic MHD simulations for the problem of Kerr black hole immersed into a rarefied plasma with ''uniform'' magnetic field. The long term solution shows properties which are significantly different ... More
The Effects of Radiation Feedback on Early Fragmentation and MultiplicityOct 20 2010Forming stars emit a significant amount of radiation into their natal environment. While the importance of radiation feedback from high-mass stars is widely accepted, radiation has generally been ignored in simulations of low-mass star formation. I use ... More