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Driving Force of Ultrafast Magnetization DynamicsAug 25 2011Irradiating a ferromagnetic material with an ultrashort laser pulse leads to demagnetization on a femtosecond timescale. We implement Elliott-Yafet type spin-flip scattering, mediated by electron-electron and electron-phonon collisions, into the framework ... More

Phase covariant quantum cloningSep 15 1999We consider an N -> M quantum cloning transformation acting on pure two-level states lying on the equator of the Bloch sphere. An upper bound for its fidelity is presented, by establishing a connection between optimal phase covariant cloning and phase ... More

Spin- and time-resolved photoemission studies of thin Co2FeSi Heusler alloy filmsMay 31 2006We have studied the possibly half metallic Co2FeSi full Heusler alloy by means of spin- and time-resolved photoemission spectroscopy. For excitation, the second and fourth harmonic of femtosecond Ti:sapphire lasers were used, with photon energies of 3.1 ... More

Towards a full Heusler alloy showing room temperature half-metallicity at the surfaceSep 20 2006In this article we investigate the surface spin polarization in a 100 nm Co2Cr0.6Fe0.4Al (CCFA) film grown ex situ epitaxially on MgO(100) with a 10 nm Fe buffer layer by means of spin resolved photoemission. We show that a careful in situ preparation ... More

Photoemission Electron Microscopy as a tool for the investigation of optical near fieldsMay 25 2005Photoemission electron microscopy was used to image the electrons photoemitted from specially tailored Ag nanoparticles deposited on a Si substrate (with its native oxide SiO$_{x}$). Photoemission was induced by illumination with a Hg UV-lamp (photon ... More

Adsorption induced pyramidal distortion of the tri-metallic nitride core inside the endohedral fullerene Sc$_3$N@C$_{80}$ on the Ag(111) surfaceMar 13 2019Our ability to understand and tailor metal-organic interfaces is mandatory to functionalize organic complexes for next generation electronic and spintronic devices. For magnetic data storage applications, metal-carrying organic molecules, so called single ... More

Epitaxial film growth and magnetic properties of Co_2FeSiJun 26 2006Sep 07 2006We have grown thin films of the Heusler compound Co_2FeSi by RF magnetron sputtering. On (100)-oriented MgO substrates we find fully epitaxial (100)-oriented and L2_1 ordered growth. On Al_2O_3 (11-20) substrates, the film growth is (110)-oriented, and ... More

Controlling singlet-triplet ratio in OLEDs by spin polarised currentsDec 02 2016Molecular spintronics has successfully crossed its first decade of life becoming an important player in the race towards the fabrication of next generation spintronic devices. The development and fabrication of spin OLEDs represents one of the key challenges ... More

Spin-flip processes and ultrafast magnetization dynamics in Co - unifying the microscopic and macroscopic view of femtosecond magnetismMay 10 2006Oct 03 2006The femtosecond magnetization dynamics of a thin cobalt film excited with ultrashort laser pulses has been studied using two complementary pump-probe techniques, namely spin-, energy- and time-resolved photoemission and time-resolved magneto-optical Kerr ... More

Structure and electronic properties of the ($\sqrt{3}\times \sqrt{3}$)$R30^{\circ}$ SnAu$_2$/Au(111) surface alloyMar 13 2019We have investigated the atomic and electronic structure of the ($\sqrt{3}\times \sqrt{3}$)$R30^{\circ}$ SnAu$_2$/Au(111) surface alloy. Low energy electron diffraction and scanning tunneling microscopy measurements show that the native herringbone reconstruction ... More

All-optical control of ferromagnetic thin films and nanostructuresMar 04 2014The interplay of light and magnetism has been a topic of interest since the original observations of Faraday and Kerr where magnetic materials affect the light polarization. While these effects have historically been exploited to use light as a probe ... More

Structural, chemical and electronic properties of the Co2MnSi(001)/MgO interfaceSep 24 2012The performance of advanced magnetic tunnel junctions build of ferromagnetic (FM) electrodes and MgO as insulating barrier depends decisively on the properties of the FM/insulator interface. Here, we investigate interface formation between the half-metallic ... More

Ultrafast demagnetization of ferromagnetic transition metals: The role of the Coulomb interactionJun 28 2009The Elliott-Yafet mechanism is arguably the most promising candidate to explain the ultrafast demagnetization dynamics in ferromagnetic transition metals on timescales on the order of 100 femtoseconds. So far, only electron-phonon scattering has been ... More

Direct determination of the surface termination in full Heusler alloys by means of low energy electron diffractionOct 26 2009Dec 18 2009The performance of Heusler based magnetoresistive multilayer devices depends crucially on the spin polarization and thus on the structural details of the involved surfaces. Using low energy electron diffraction (LEED), one can non-destructively distinguish ... More

Surface spin polarization of the non-stoichiometric Heusler compound Co2Mn(alpha)SiOct 25 2011Oct 28 2011Using a combined approach of spin-resolved photoemission spectroscopy, band structure and photoemission calculations we investigate the influence of bulk defects and surface states on the spin polarization of Co2Mn(alpha)Si thin films with bulk L21 order. ... More

Topological States on the Gold SurfaceApr 08 2015Gold surfaces host special electronic states that have been understood as a prototype of Shockley surface states (SSs). These SSs are commonly employed to benchmark the capability of angle-resolved photoemission spectroscopy (ARPES) and scanning tunneling ... More

Light localisation and magneto-optic enhancement in Ni anti-dot arraysJul 20 2015Dec 27 2015The excitation of surface plasmons in magnetic nano-structures can strongly influence their magneto-optical properties. Here, we use photoemission electron microscopy to map the spatial distribution of the electric near-field on a nano-patterned magnetic ... More

Light-induced magnetization reversal of high-anisotropy TbCo alloy filmsJun 29 2012Magnetization reversal using circularly polarized light provides a new way to control magnetization without any external magnetic field and has the potential to revolutionize magnetic data storage. However, in order to reach ultra-high density data storage, ... More

Revealing the spin and symmetry properties of the buried Co2MnSi/MgO interface by low energy spin-resolved photoemissionSep 19 2012We present a novel approach to study the spin and symmetry electronic properties of buried interfaces using low-energy spin-resolved photoemission spectroscopy. We show that this method is sensitive to interfaces buried below more than 20ML (~4nm) MgO, ... More

Lorentz Conserving Noncommutative Standard ModelMar 29 2007May 10 2007We consider Lorentz conserving noncommutative field theory to construct the Lorentz conserving noncommutative standard model based on the gauge group $SU(3)\times SU(2)\times U(1)$. We obtain the enveloping algebra-valued of Higgs field up to the second ... More

Shelving and Probe Efficiency in Trapped Ion ExperimentsFeb 24 2014A generalized probe sequence typical of trapped ion experiments using shelving is studied. Detection efficiency is analyzed for finite shelved state lifetimes and using multi-modal count distributions. Multi-modal distributions are more appropriate for ... More

The Neutralino Relic Density in Minimal N=1 SupergravityJul 10 1992We compute the cosmic relic (dark matter) density of the lightest supersymmetric particle (LSP) in the framework of minimal $N=1$ Supergravity models with radiative breaking of the electroweak gauge symmetry. To this end, we re--calculate the cross sections ... More

Quantization and $2π$ Periodicity of the Axion Action in Topological InsulatorsJun 17 2010Nov 10 2010The Lagrangian describing the bulk electromagnetic response of a three-dimensional strong topological insulator contains a topological `axion' term of the form '\theta E dot B'. It is often stated (without proof) that the corresponding action is quantized ... More

A new signal for scalar top bound state productionOct 01 1993We study the production and decay of a scalar \stst\ bound state \sigst\ at hadron supercolliders, where \st\ is the lighter stop eigenstate. If \st\ has no tree--level 2--body decays, the dominant decay modes of \sigst\ are $gg$ or, if $m_h < \mst \ll ... More

Massive Neutrino in Non-commutative Space-timeDec 24 2007Apr 01 2008We consider the noncommutative standard model based on $SU(3)\times SU(2)\times U(1)$. We study the gauge transformation of right handed neutrino and its direct interaction with photon in the noncommutative space-time. We show that the massive Dirac neutrinos, ... More

Infinite order excitonic Bloch equations for asymmetric nanostructuresJul 04 2003We present a new exciton-based formalism for calculating the coherent response of asymmetric semiconductor multiple quantum well structures to ultra-short optical pulses valid to infinite order in the optical field and including the self-generated intraband ... More

Scalar StoponiumAug 18 1993We study the decays of a scalar \stst\ bound state \sigst, where \st\ is the lighter stop eigenstate. If \st\ has no tree--level 2--body decays, the dominant decay modes of \sigst\ are $gg$ or, if $m_h < \mst \ll \mstt$, a pair of light scalar Higgs bosons ... More

Neutralino-Nucleon Scattering RevisitedJul 01 1993We present a detailed discussion of the elastic scattering of a supersymmetric neutralino off a nucleon or nucleus, with emphasis on the spin--independent interaction. We carefully treat QCD effects on the squark exchange contribution. In particular, ... More

Quantum information processing: The case of vanishing interaction energyOct 27 2002We investigate the rate of operation of quantum "black boxes" ("oracles") and point out the possibility of performing an operation by a quantum "oracle" whose average energy equals zero. This counterintuitive result not only presents a generalization ... More

Self-Organized Topological State with Majorana FermionsJul 08 2013Nov 06 2013Topological phases, quite generally, are difficult to come by. They either occur under rather extreme conditions (e.g. the quantum Hall liquids, which require high sample purity, strong magnetic fields and low temperatures) or demand fine tuning of system ... More

Spin Response of Electrons on the Surface of a Topological InsulatorJan 11 2012The surface of a topological insulator hosts a very special form of a quasi-two dimensional metallic system when it is embedded in a topologically trivial medium like the vacuum. The electronic properties of this unusual 2D metal are distinct in many ... More

Photon Neutrino Scattering in Non-Commutative SpaceNov 04 2005Jan 19 2006We extend the non-commutative standard model based on the minimal $SU(3)\times SU(2)\times U(1)$ gauge group to include the interaction of photon with neutrino. We show that, in the gauge invariant manner, only the right handed neutrino can directly couple ... More

Fredholm determinants and pole-free solutions to the noncommutative Painleve' II equationJan 20 2011We extend the formalism of integrable operators a' la Its-Izergin-Korepin-Slavnov to matrix-valued convolution operators on a semi-infinite interval and to matrix integral operators with a kernel of the form E_1^T(x) E_2(y)/(x+y) thus proving that their ... More

The gap probabilities of the tacnode, Pearcey and Airy point processes, their mutual relationship and evaluationMar 12 2013May 10 2013We express the gap probabilities of the tacnode process as the ratio of two Fredholm determinants; the denominator is the standard Tracy-Widom distribution, while the numerator is the Fredholm determinant of a very explicit kernel constructed with Airy ... More

Point distributions in compact metric spacesDec 01 2015We consider finite point subsets (distributions) in compact metric spaces. Non-trivial bounds for sums of distances between points of distributions and for discrepancies of distributions in metric balls are given in the case of general rectifiable metric ... More

Distribution of the very first PopIII stars and their relation to bright z~6 quasarsMay 25 2007We discuss the link between dark matter halos hosting the first PopIII stars and the rare, massive, halos that are generally considered to host bright quasars at high redshift z~6. The main question that we intend to answer is whether the super-massive ... More

Double deeply virtual Compton scattering off the nucleonAug 30 2002We study the double deeply virtual Compton scattering (DDVCS) process off the nucleon, through the scattering of a spacelike virtual photon with large virtuality resulting in the production of a timelike virtual photon, decaying into an e^+ e^- pair. ... More

Deeply Virtual Electroproduction of Photons and MesonsJan 13 1999In this paper, after a brief summary of the properties of the Off-Forward Parton Distributions, we give some examples of what could be the experimental opportunities to access them at the current high-energy lepton facilities : JLab (E_e >= 6 GeV), HERMES ... More

Direct J/psi and psi' Polarization and Cross Sections at the TevatronNov 03 1996Transverse polarization of ${}^3 S_1$ charmonium states, produced directly in $p\bar{p}$ collisions at asymptotically large transverse momentum p_t, has emerged as the most prominent test of color octet contributions and spin symmetry in quarkonium production. ... More

Strange quark matter with dynamically generated quark massesOct 29 1998Apr 27 1999Bulk properties of strange quark matter (SQM) are investigated within the SU(3) Nambu-Jona-Lasinio model. In the chiral limit the model behaves very similarly to the MIT bag model which is often used to describe SQM. However, when we introduce realistic ... More

Sum Rules for Multi-Photon Spectroscopy of Ions in Finite SymmetryNov 18 1998Models describing one- and two-photon transitions for ions in crystalline environments are unified and extended to the case of parity-allowed and parity- forbidden p-photon transitions. The number of independent parameters for characterizing the polarization ... More

Parton densities from LHC vector boson production at small and large transverse momentaMay 24 2013Nov 07 2013The parton densities of the proton are of fundamental importance not only for our description of hadronic and nuclear structure, but also for reliable predictions for new heavy particle searches at colliders. At the large partonic momentum fractions required ... More

Search for gamma-ray-emitting active galactic nuclei in the Fermi-LAT unassociated sample using machine learningDec 19 2013The second Fermi-LAT source catalog (2FGL) is the deepest all-sky survey available in the gamma-ray band. It contains 1873 sources, of which 576 remain unassociated. Machine-learning algorithms can be trained on the gamma-ray properties of known active ... More

Pressure imbalance of FRII radio source lobes: a role of energetic proton populationMar 12 2001Recently Hardcastle & Worrall (MNRAS, 319, 562) analyzed 63 FRII radio galaxies imbedded in the X-ray radiating gas in galaxy clusters and concluded, that pressures inside its lobes seem to be a factor of a few lower than in the surrounding gas. One of ... More

Limits on Nonstandard Forces in the Submicrometer RangeApr 12 2009May 01 2009We report the search for a nonstandard force by measuring the Casimir forces in the 0.48--6.5 $\mu$m range. By comparing the data and the theory of the Casimir force, we have obtained constraints for the parameter $\alpha$ of the Yukawa-type deviations ... More

Unweighted event generation in hadronic WZ production at order(alpha_S)Nov 16 2000We present an algorithm for unweighted event generation in the partonic process pp -> WZ (j) with leptonic decays at next-to-leading order in alpha_S. Monte Carlo programs for processes such as this frequently generate events with negative weights in ... More

Time-resolved noise of adiabatic quantum pumpsSep 22 2006We investigate quantum-statistical correlation properties of a periodically driven mesoscopic scatterer on a time-scale shorter than the period of a drive. In this limit the intrinsic quantum fluctuations in the system of fermions are the main source ... More

Elliptical torii in a constant magnetic fieldSep 23 2005The Schrodinger equation for an electron on the surface of an elliptical torus in the presence of a constant azimuthally symmetric magnetic field is developed. The single particle spectrum and eigenfunctions as a function of magnetic flux through the ... More

Temperature and pH driven association in uranyl aqueous solutionsDec 27 2012An association behavior of uranyl ions in aqueous solutions is explored. For this purpose a set of all-atom molecular dynamics simulations is performed. During the simulation, the fractions of uranyl ions involved in dimer and trimer formations were monitored. ... More

Cluster structure of EU-15 countries derived from the correlation matrix analysis of macroeconomic index fluctuationsJul 11 2006The statistical distances between countries, calculated for various moving average time windows, are mapped into the ultrametric subdominant space as in classical Minimal Spanning Tree methods. The Moving Average Minimal Length Path (MAMLP) algorithm ... More

Fringe Visibility Estimators for the Palomar Testbed InterferometerOct 28 1998Visibility estimators and their performance are presented for use with the Palomar Testbed Interferometer (PTI). One operational mode of PTI is single-baseline visibility measurement using pathlength modulation with synchronous readout by a NICMOS-3 infrared ... More

Forward Compton Scattering, using Real Analytic AmplitudesApr 04 2002Apr 22 2002We analyze forward Compton scattering, using real analytic amplitudes. By fitting the total \gamma p scattering cross section data in the high energy region 5 GeV < \sqrt s < 20 GeV, using a cross section rising as \ln^2 s, we calculate \rho_{\gamma p}, ... More

Effective Potential for Scalar Field in Three Dimensions: Ising Model in the Ferromagnetic PhaseJan 29 1996We compute the effective potential $V_{\rm eff}(\phi)$ for one-component real scalar field $\phi$ in three Euclidean dimensions (3D) in the case of spontaneously broken symmetry, from the Monte Carlo simulation of the 3D Ising model in external field ... More

Regularization by noise and stochastic Burgers equationsAug 31 2012Apr 09 2013We study a generalized 1d periodic SPDE of Burgers type: $$ \partial_t u =- A^\theta u + \partial_x u^2 + A^{\theta/2} \xi $$ where $\theta > 1/2$, $-A$ is the 1d Laplacian, $\xi$ is a space-time white noise and the initial condition $u_0$ is taken to ... More

Beam Fragmentation in Heavy Ion Collisions with Realistically Correlated Nuclear ConfigurationsAug 13 2010Apr 24 2011We develop a new approach to production of the spectator nucleons in the heavy ion collisions. The energy transfer to the spectator system is calculated using the Monte Carlo based on the updated version of our generator of configurations in colliding ... More

A Remark on Supersymmetric Bubbles and Spectrum CrossoverAug 22 2012Using an exact expression for the domain wall tension in a supersymmetric model we show that a spectrum crossover takes place in passing from weak to strong coupling. In the weak coupling regime elementary excitations are the lightest states, while in ... More

Statistical approach based on 1D Voronoi tessellation as a tool for studying the randomness of fractional digits of some irrational numbersMay 19 2015An "experimental" study on the randomness of the fractional digits of $\pi$, $e$ and $\phi$ irrational numbers are presented. This is done by exploiting the $1D$ Poisson-Voronoi tessellation. We employed two approaches and in both cases, within the numerical ... More

Beyond the constraints underlying Kolmogorov-Johnson-Mehl-Avrami theory related to the growth lawsJan 20 2012The theory of Kolmogorov-Johnson-Mehl-Avrami (KJMA) for phase transition kinetics is subjected to severe limitations concerning the functional form of the growth law. This paper is devoted to side step this drawback through the use of correlation function ... More

Black hole formation by incoming electromagnetic radiationAug 12 2014Aug 18 2014I revisit a known solution of the Einstein field equations to show that it describes the formation of non-spherical black holes by the collapse of pure electromagnetic monochromatic radiation. Both positive and negative masses are feasible without ever ... More

Algebraic classification of the Weyl tensor in higher dimensions based on its "superenergy" tensorAug 16 2010Mar 28 2011The algebraic classification of the Weyl tensor in arbitrary dimension n is recovered by means of the principal directions of its "superenergy" tensor. This point of view can be helpful in order to compute the Weyl aligned null directions explicitly, ... More

On the existence of horizons in spacetimes with vanishing curvature invariantsNov 19 2003A direct very simple proof that there can be no closed trapped surfaces (ergo no black hole regions) in spacetimes with all curvature scalar invariants vanishing is given. Explicit examples of the recently introduced ``dynamical horizons'' which nevertheless ... More

Super-energy tensorsJun 21 1999A purely algebraic construction of super-energy tensors for arbitrary fields is presented in any dimensions. These tensors have good mathematical and physical properties, and they can be used in any theory having as basic arena an n-dimensional manifold ... More

(Super)^n-Energy for arbitrary fields and its interchange: Conserved quantitiesMay 17 1999Inspired by classical work of Bel and Robinson, a natural purely algebraic construction of super-energy tensors for arbitrary fields is presented, having good mathematical and physical properties. Remarkably, there appear quantities with mathematical ... More

Trapped surfacesJul 07 2011Sep 14 2011I review the definition and types of (closed) trapped surfaces. Surprising global properties are shown, such as their "clairvoyance" and the possibility that they enter into flat portions of the spacetime. Several results on the interplay of trapped surfaces ... More

A Reformulation of the Hoop ConjectureSep 05 2007Dec 04 2007A reformulation of the Hoop Conjecture based on the concept of trapped circle is presented. The problems of severe compactness in every spatial direction, and of how to superpose the hoops with the surface of the black hole, are resolved. A new conjecture ... More

Remarks on Superenergy TensorsJan 07 1999We define super-energy tensors for arbitrary physical fields, including the gravitational, electromagnetic and massless scalar fields. We also define super-super-energy tensors, and so on. All these tensors satisfy the so-called "Dominant Superenergy ... More

Complete Two Loop Electroweak Contributions to the Muon Lifetime in the Standard ModelMay 22 2003May 26 2003An independent result for the two loop fermionic contributions to the muon lifetime in the Standard Model is obtained. Deviations are found with respect to \cite{Freitas:2000gg}, which result in a shift of the W boson mass by approximately -1.3 MeV over ... More

Complete Two Loop Bosonic Contributions to the Muon Lifetime in the Standard ModelAug 12 2002Nov 15 2002The last missing correction to the muon lifetime in the Standard Model at O(alpha^2) coming from gauge and Higgs boson loops is presented. The associated contribution to the parameter Delta r in the on-shell scheme ranges from 6 times 10^{-5} to -4 times ... More

Sungrazing comets as source of pickup ions at Earth orbit and UlyssesJul 04 2005Most of the sungrazing comets observed by LASCO at SOHO belong to the Kreutz group of comets and follow trajectories that are tightly clumped in space. Statistical analysis of 9 years of SOHO observations suggests that the true apparition rate of these ... More

On the smallest screening masses in hot QCDJun 24 2009Sep 03 2009The increasing focus on unquenched lattice simulations has revived interest also in gluonic screening masses, whose inverses characterise the longest length scales at which thermal fluctuations are correlated in a hot non-Abelian plasma. We fill an apparent ... More

Mesonic correlation lengths in high-temperature QCDNov 21 2003Mar 01 2004We consider spatial correlation lengths \xi for various QCD light quark bilinears at temperatures above a few hundred MeV. Some of the correlation lengths (such as that related to baryon density) coincide with what has been measured earlier on from glueball-like ... More

Super-light electromagnetic wave with longitudinal and transversal modesAug 20 2007The transformation converting equations invariant under Lorentz into the equations invariant under Galileo is obtained. On this basis: (1) the super-light electromagnetic wave with longitudinal and transversal modes is found out; (2) it is shown the wave ... More

Near-Infrared Properties of Type Ia SupernovaeNov 18 2011Feb 17 2012The photometric properties of Type Ia supernovae (SNe Ia) in the near-infrared as garnered from observations made over the last 30 years are reviewed. During this period, light curves for more than 120 nearby SNe Ia have been published, revealing considerable ... More

Accurate Estimates of 3D Ising Critical Exponents Using the Coherent-Anomaly MethodNov 26 1994An analysis of the critical behavior of the three-dimensional Ising model using the coherent-anomaly method (CAM) is presented. Various sources of errors in CAM estimates of critical exponents are discussed, and an improved scheme for the CAM data analysis ... More

Flat (001) surfaces of II-VI semiconductors: A lattice gas modelNov 07 2001We present a two-dimensional lattice gas with anisotropic interactions which model the known properties of the surface reconstructions of CdTe and ZnSe. In constrast to an earlier publication [12], the formation of anion dimers is considered. This alters ... More

HST - WFPC2 photometry of the globular cluster ngc 288: binary systems, blue stragglers and very blue starsOct 28 1999We report on new WFPC2 observations of the globular cluster NGC 288, focusing our attention on peculiar stars. A very pronounced binary sequence, paralleling the ordinary Main Sequence (MS) is clearly observed in the Color Magnitude Diagram (CMD) and ... More

Wormhole and Hawking RadiationJul 29 1993Aug 12 1993It is shown in a variant of two dimensional dilaton gravity theories that an arbitrary, localized massive source put in an initially regular spacetime gives rise to formation of the wormhole classically, without accompanying the curvature singularity. ... More

${\bar p} p$ Annihilation: Manifestations of Instanton Induced Quark Pair Production ?Dec 26 1994Production of strangeness in the low-energy ${\bar p} p$ annihilation is analyzed as a manifestation of the instanton induced multiquark vertex. Approach based on the {\it qualitative} properties of the 't Hooft mechanism provides a unified description ... More

Coherent spin dynamics of electrons and excitons in nanostructuresJan 03 2012The studies of spin phenomena in semiconductor low dimensional systems have grown into the rapidly developing area of the condensed matter physics: spintronics. The most urgent problems in this area, both fundamental and applied, are the creation of charge ... More

Paracontrolled quasilinear SPDEsOct 25 2016Nov 11 2016We introduce a non-linear paracontrolled calculus and use it to renormalise a class of singular SPDEs including certain quasilinear variants of the periodic two dimensional parabolic Anderson model.

Feedback in AGN heating of galaxy clustersMay 21 2004One of the challenges that models of AGN heating of the intracluster medium (ICM) face, is the question how the mechanical luminosity of the AGN is tuned to the radiative losses of the ICM. Here we implement a simple 1D model of a feedback mechanism that ... More

Accelerating numerical solution of Stochastic Differential Equations with CUDAMar 23 2009Aug 12 2009Numerical integration of stochastic differential equations is commonly used in many branches of science. In this paper we present how to accelerate this kind of numerical calculations with popular NVIDIA Graphics Processing Units using the CUDA programming ... More

Regular R-R and NS-NS BPS black holesOct 28 1999May 24 2000We show in a precise group theoretical fashion how the generating solution of regular BPS black holes of N=8 supergravity, which is known to be a solution also of a simpler N=2 STU model truncation, can be characterized as NS-NS or R-R charged according ... More

A more general treatment of the philosophy of physics and the existence of universesJun 07 2013Natural philosophy necessarily combines the process of scientific observation with an abstract (and usually symbolic) framework, which provides a logical structure to the development of a scientific theory. The metaphysical underpinning of science includes ... More

Equivariant Novikov inequalitiesOct 26 1996Oct 28 1996We establish an equivariant generalization of the Novikov inequalities which allow to estimate the topology of the set of critical points of a closed basic invariant form by means of twisted equivariant cohomology of the manifold. We apply these inequalities ... More

Positronium contribution to the electron g-2Feb 07 2014Sep 25 2014The contribution of positronium to the electron $g$-2 ($a_e$) has been computed in Ref. [1] and found to be of the same order of $\alpha$ as that of five-loop perturbative QED. We confirm this result and correct a few errors in its first derivation. As ... More

Reheating during Hierarchical Clustering in the Universe Dominated by the Cold Dark MatterSep 25 1993We investigate reheating of the universe by early formation of stars and quasars in the hierarchical clustering scheme of cold dark matter scenario, with perturbation fluctuations normalized by the COBE data. It is found that ionizing uv flux from OB ... More

Boundary layer emission in luminous LMXBsDec 14 2005We show that aperiodic and quasiperiodic variability of bright LMXBs - atoll and Z- sources, on ~sec - msec time scales is caused primarily by variations of the boundary layer luminosity. The accretion disk emission is less variable on these time scales ... More

Spherical Thin-Shell Wormholes and Modified Chaplygin GasSep 28 2013The purpose of this paper is to construct spherical thin-shell wormhole solutions through cut and paste technique and investigate the stability of these solutions in the vicinity of modified Chaplygin gas. The Darmois-Israel formalism is used to formulate ... More

Singularities in Isotropic Non-Minimal Scalar Field ModelsApr 24 2006Non-minimally coupling a scalar field to gravity introduces an additional curvature term into the action which can change the general behavior in strong curvature regimes, in particular close to classical singularities. While one can conformally transform ... More

Calculation of the Phase Behavior of LipidsFeb 24 1998The self-assembly of monoacyl lipids in solution is studied employing a model in which the lipid's hydrocarbon tail is described within the Rotational Isomeric State framework and is attached to a simple hydrophilic head. Mean-field theory is employed, ... More

Chemical Evolution of CNO abundancesFeb 05 2003New low and intermediate star yields calculated by Buell (1997) are evaluated by using them in a Galactic Chemical Evolution model. We analyze their effects on CNO elemental abundances

Evolution of QCD Coupling Constant at Finite Temperature in the Background Field MethodSep 04 1995The evolution of QCD coupling constant at finite temperature is considered by making use of the finite temperature renormalization group equation up to the one-loop order in the background field method with the Feynman gauge and the imaginary time formalism. ... More

Hamiltonian, Energy and Entropy in General Relativity with Non-Orthogonal BoundariesJul 23 2001A general recipe to define, via Noether theorem, the Hamiltonian in any natural field theory is suggested. It is based on a Regge-Teitelboim-like approach applied to the variation of Noether conserved quantities. The Hamiltonian for General Relativity ... More

Statistical mechanics of dissipative systemsApr 06 2002We propose a generalization of classical statistical mechanics which describes the behavior of dissipative systems placed in contact with a heat bath. In contrast to conventional statistical mechanics, which assigns probabilities to the states of the ... More

Kolmogorov spectrum of superfluid turbulence: numerical analysis of the Gross-Pitaevskii equation with the small scale dissipationNov 30 2004The energy spectrum of superfluid turbulence is studied numerically by solving the Gross-Pitaevskii equation. We introduce the dissipation term which works only in the scale smaller than the healing length, to remove short wavelength excitations which ... More

A counterexample to dispersive estimates for Schrödinger operators in higher dimensionsAug 11 2005In dimension $n>3$ we show the existence of a compactly supported potential in the differentiability class $C^\alpha$, $\alpha < \frac{n-3}2$, for which the solutions to the linear Schr\"odinger equation in $\R^n$, $$ -i\partial_t u = - \Delta u + Vu, ... More

Cosmic evolution in the background of non-minimal coupling in $f(R,T,R_{μν}T^{μν})$ GravityMay 08 2018An accelerated expansion phase is being experienced by the universe due to the presence of an unknown energy component known as dark energy (DE). To find out the cosmic evolution scientists ever tried to modify Einstein's gravitational theory and its ... More

Symmetry and the Union of Saturated Models in Superstable Abstract Elementary ClassesDec 06 2015Dec 19 2015Our main result (Theorem 1) suggests a possible dividing line ($\mu$-superstable $+$ $\mu$-symmetric) for abstract elementary classes without using extra set-theoretic assumptions or tameness. This theorem illuminates the structural side of such a dividing ... More

Inter-molecular structure factors of macromolecules in solution: integral equation resultsApr 19 1999The inter-molecular structure of semidilute polymer solutions is studied theoretically. The low density limit of a generalized Ornstein-Zernicke integral equation approach to polymeric liquids is considered. Scaling laws for the dilute-to-semidilute crossover ... More