Results for "L. Mogg"

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Perfect proton selectivity in ion transport through two-dimensional crystalsAug 21 2019Defect-free monolayers of graphene and hexagonal boron nitride were previously shown to be surprisingly permeable to thermal protons, despite being completely impenetrable to all gases. It remains untested whether small ions can permeate through the two-dimensional ... More
Perfect proton selectivity in ion transport through two-dimensional crystalsAug 21 2019Aug 31 2019Defect-free monolayers of graphene and hexagonal boron nitride were previously shown to be surprisingly permeable to thermal protons, despite being completely impenetrable to all gases. It remains untested whether small ions can permeate through the two-dimensional ... More
Atomically-thin micas as proton conducting membranesJun 11 2019Monolayers of graphene and hexagonal boron nitride (hBN) are highly permeable to thermal protons. For thicker two-dimensional (2D) materials, proton conductivity diminishes exponentially so that, for example, monolayer MoS2 that is just three atoms thick ... More
Anisotropy of the superconducting fluctuations in multiband superconductors: the case of LiFeAsJul 08 2014Nov 14 2014Between the different families of pnictide multiband superconductors, LiFeAs is probably one of the less understood. Indeed, despite the large amount of experiments performed in the last few years on this material, no consensus has been reached yet on ... More
Gedanken Experiments involving Black HolesAug 20 1993Analysis of several gedanken experiments indicates that black hole complementarity cannot be ruled out on the basis of known physical principles. Experiments designed by outside observers to disprove the existence of a quantum-mechanical stretched horizon ... More
On the measure of Lagrangian invariant tori in nearly--integrable mechanical systems (draft)Mar 27 2015Consider a real--analytic nearly--integrable mechanical system with potential $f$, namely, a Hamiltonian system, having a real-analytic Hamiltonian $$ H(y,x)=\frac12 | y |^2 +\e f(x)\ , $$ $y,x$ being $n$--dimensional standard action--angle variables ... More
On the Evaluation and Comparison of Taggers: The Effect of Noise in Testing CorporaSep 28 1998This paper addresses the issue of {\sc pos} tagger evaluation. Such evaluation is usually performed by comparing the tagger output with a reference test corpus, which is assumed to be error-free. Currently used corpora contain noise which causes the obtained ... More
Poisson-Lie T-plurality of three-dimensional conformally invariant sigma models II: Nondiagonal metrics and dilaton puzzleAug 17 2004Sep 29 2005We look for 3-dimensional Poisson-Lie dualizable sigma models that satisfy the vanishing beta-function equations with constant dilaton field. Using the Poisson-Lie T-plurality we then construct 3-dimensional sigma models that correspond to various decompositions ... More
Classification of 6-dimensional real Manin triplesFeb 21 2002Mar 27 2002We present a complete list of 6-dimensional Manin triples or, equivalently, of 3-dimensional Lie bialgebras. We start from the well known classification of 3-dimensional real Lie algebras and assume the canonical bilinear form on the 6-dimensional Drinfeld ... More
Renormalizability of semiquantized fieldsOct 03 1994Sep 21 1995A definition is given, in the framework of stochastic quantization, for the dynamics of a system composed of classical and quantum degrees of freedom mutually interacting. It is found that the theory breaks reflection positivity, and hence it is unphysical. ... More
Leading order one-loop CP and P violating effective action in the Standard ModelFeb 11 2011The fermions of the Standard Model are integrated out to obtain the effective Lagrangian in the sector violating P and CP at zero temperature. We confirm that no contributions arise for operators of dimension six or less and show that the leading operators ... More
Quantum Bounded Symmetric DomainsMar 26 2008Oct 13 2010This is Leonid Vaksman's monograph "Quantum bounded symmetric domains" (in Russian), preceded with an English translation of the table of contents and (a part) of the introduction. Quantum bounded symmetric domains are interesting from several points ... More
On a multidimentional Brownian motion with partly reflecting membrane on a hyperplaneOct 30 2012A multidimensional Brownian motion with partial reflection on a hyperplane $S$ in the direction $qN+\alpha $, where $N$ is the conormal vector to the hyperplane and $q\in [-1,1], \alpha \in S$ are given parametres, is constructed and this construction ... More
Active Ornstein-Uhlenbeck particlesMay 13 2019Aug 08 2019Active Ornstein-Uhlenbeck particles (AOUPs) are overdamped particles in an interaction potential subject to external Ornstein-Uhlenbeck noises. They can be transformed into a system of underdamped particles under additional velocity dependent forces and ... More
Supersymmetric domain wall x G/H solutions of IIB supergravityApr 23 20011-brane nonmaximally supersymmetric solutions of D=10 chiral supergravity are discussed. In the dual frame, their near brane geometry is the product of a 3-dimensional domain wall spacetime and a 7-dimensional homogeneous Einstein space G/H.
Hawking Radiation and Back-ReactionMar 20 1992The puzzles of black hole evaporation can be studied in the simplified context of 1+1 dimensional gravity. The semi-classical equations of Callan, Giddings, Harvey and Strominger provide a consistent description of the evaporation process which we describe ... More
Minimal surfaces bounded by elastic linesAug 02 2011May 30 2012In mathematics, the classical Plateau problem consists of finding the surface of least area that spans a given rigid boundary curve. A physical realization of the problem is obtained by dipping a stiff wire frame of some given shape in soapy water and ... More
Solution of a Yang-Baxter systemNov 04 1998Nov 05 1998Yang-Baxter system related to quantum doubles is introduced and large class of both continuous and discrete symmetries of the solution manifold are determined. Strategy for solution of the system based on the symmetries is suggested and accomplished in ... More
Does the complex Langevin method give unbiased results?Nov 19 2016We investigate whether the stationary solution of the Fokker-Planck equation of the complex Langevin algorithm reproduces the correct expectation values. When the complex Langevin algorithm for an action $S(x)$ is convergent, it produces an equivalent ... More
Comment on "Quantum back-reaction through the Bohmian particle"Feb 17 2003In this Comment I point out some limitations of the proposal of Prezhdo and Brooksby for coupling quantum and classical degrees of freedom (Phys.Rev.Lett.86(2001)3215) if it is pushed too far.
Generalized heat kernel coefficientsJul 16 2001Sep 26 2001Following Osipov and Hiller, a generalized heat kernel expansion is considered for the effective action of bosonic operators. In this generalization, the standard heat kernel expansion, which counts inverse powers of a c-number mass parameter, is extended ... More
Comment on ``A quantum-classical bracket that satisfies the Jacobi identity'' [J. Chem. Phys. 124, 201104 (2006)]Jan 10 2007It shown that the quantum-classical dynamical bracket recently proposed in J. Chem. Phys. 124, 201104 (2006) fails to satisfy the Jacobi identity.
Minimum uncertainty for antisymmetric wave functionsJun 05 1997We study how the entropic uncertainty relation for position and momentum conjugate variables is minimized in the subspace of one-dimensional antisymmetric wave functions. Based partially on numerical evidence and partially on analytical results, a conjecture ... More
Chiral asymmetry of the spin-wave spectra in ultrathin magnetic filmsJan 19 2009We raise the possibility that the chiral degeneracy of the magnons in ultrathin films can be lifted due to the presence of Dzyaloshinskii-Moriya interactions. By using simple symmetry arguments, we discuss under which conditions such a chiral asymmetry ... More
Optical Doppler shift measurement using a rotating mirrorJul 24 2006Sep 22 2006Optical Doppler shift demonstration experiments are not a simple task since the light source cannot usually be moved in a sufficiently smooth and uniform manner to keep the level of noise well below of that of the signal. For that reason most demonstration ... More
Positive representations of complex distributions on groupsMay 04 2018Oct 29 2018A normalizable complex distribution $P(x)$ on a manifold $\mathcal{M}$ can be regarded as a complex weight, thereby allowing to define expectation values of observables $A(x)$ defined on $\mathcal{M}$. Straightforward importance sampling, $x\sim P$, is ... More
Stability of a Time-varying Fishing Model with DelayJan 19 2006We introduce a delay nonlinear differential equation model which describes how fish are harvested. In our previous studies we investigated the persistence of that equation and existence of a periodic solution for this equation. Here we study the stability ... More
Theory of charge fluctuations and domain relocation times in semiconductor superlatticesDec 07 2004Shot noise affects differently the nonlinear electron transport in semiconductor superlattices depending on the strength of the coupling among the superlattice quantum wells. Strongly coupled superlattices can be described by a miniband Boltzmann-Langevin ... More
New AdS(3) x G/H compactifications of chiral IIB supergravityMar 13 2000May 30 2000We present a new class of solutions of D=10, N=2 chiral supergravity. A nonvanishing background for the field strength G_{MNR} of the complex two-form triggers AdS_3 x M_7 compactifications, where M_7 is a 7-dimensional compact manifold. When M_7 is a ... More
Detailed analysis of quantum phase transitions within the $u(2)$ algebraOct 13 2009We analyze in detail the quantum phase transitions that arise in models based on the $u(2)$ algebraic description for bosonic systems with two types of scalar bosons. First we discuss the quantum phase transition that occurs in hamiltonians that admix ... More
Recent Results on $\psip$ Decays at BesMay 16 2005Recent results on $\psip$ decays, including 10 Vector + Pseudoscalar (VP) modes and $p\bar{p}\pi^0(\eta)$, are reported with $14\times10^6$ $\psip$ events collected with the BESII detector. Cross sections and form factors for $e^+e^- \to \wpi$, $\rho\eta$, ... More
Statistical consistency of quantum-classical hybridsJan 20 2012After formulating a no-go theorem for perfect quantum-classical hybrid systems, a new consistency requirement based on standard statistical considerations is noted. It is shown that such requirement is not fulfilled by the mean-field approach, nor by ... More
Derivative expansion of the heat kernel in curved spaceJun 13 2007Jul 02 2007The heat kernel in curved space-time is computed to fourth order in a strict expansion in the number of covariant derivatives. The computation is made for arbitrary non abelian gauge and scalar fields and for the Riemann connection in the coordinate sector. ... More
Phase space localization of antisymmetric functionsNov 05 2002Upper and lower bounds are written down for the minimum information entropy in phase space of an antisymmetric wave function in any number of dimensions. Similar bounds are given when the wave function is restricted to belong to any of the proper subspaces ... More
On the uniqueness of the expected stress-energy tensor in renormalizable field theoriesMar 15 1999Sep 17 1999It is argued that the ambiguity introduced by the renormalization in the effective action of a four-dimensional renormalizable quantum field theory is at most a local polynomial action of canonical dimension four. The allowed ambiguity in the expected ... More
Direct construction of the effective action of chiral gauge fermions in the anomalous sectorApr 14 2008Jul 25 2008The anomaly implies an obstruction to a fully chiral covariant calculation of the effective action in the abnormal parity sector of chiral theories. The standard approach then is to reconstruct the anomalous effective action from its covariant current. ... More
The induced Chern-Simons term at finite temperatureJan 09 2002It is argued that the derivative expansion is a suitable method to deal with finite temperature field theory, if it is restricted to spatial derivatives only. Using this method, a simple and direct calculation is presented for the radiatively induced ... More
On the active Ornstein-Uhlenbeck particlesMay 13 2019Active Ornstein-Uhlenbeck particles (AOUPs) are overdamped particles in an interaction potential subject to external Ornstein-Uhlenbeck noises. They can be transformed into a system of underdamped particles under additional velocity dependent forces and ... More
The Effect of Weak Gravitational Lensing on the Angular Distribution of Gamma-Ray BurstsJun 10 1996If Gamma-Ray Bursts (GRBs) are cosmologically distributed standard candles and are associated with the luminous galaxies, then the observed angular distribution of all GRBs is altered due to weak gravitational lensing of bursts by density inhomogeneities. ... More
Double Hall instability: A catalyzer of magnetic energy releaseMay 29 2017Oct 03 2017A pictorial explanation for shear-Hall instability is suggested and shows that the shear flow is not necessary for the instability because its role can be played by the Hall effect of an inhomogeneous background magnetic field. Linear stability analysis ... More
Expansion of a Bose-Einstein Condensate in an atomic waveguideNov 15 2001The expansion of a Bose-Einstein condensate in an atomic waveguide is analyzed. We study different regimes of expansion, and identify a transient regime between one-dimensional and three-dimensional dynamics, in which the properties of the condensate ... More
Classification of Poisson-Lie T-dual models with two-dimensional targetsOct 16 2001Dec 20 2001Four-dimensional Manin triples and Drinfeld doubles are classified and corresponding two-dimensional Poisson-Lie T-dual sigma models on them are constructed. The simplest example of a Drinfeld double allowing decomposition into two nontrivially different ... More
Statistical Mechanics of Developable RibbonsFeb 24 2010Jun 11 2010We investigate the statistical mechanics of long developable ribbons of finite width and very small thickness. The constraint of isometric deformations in these ribbon-like structures that follows from the geometric separation of scales introduces a coupling ... More
A bracket polynomial for graphsAug 25 2008Jan 14 2009A knot diagram has an associated looped interlacement graph, obtained from the intersection graph of the Gauss diagram by attaching loops to the vertices that correspond to negative crossings. This construction suggests an extension of the Kauffman bracket ... More
Chapman-Enskog method and synchronization of globally coupled oscillatorsJun 12 2000Jul 10 2000The Chapman-Enskog method of kinetic theory is applied to two problems of synchronization of globally coupled phase oscillators. First, a modified Kuramoto model is obtained in the limit of small inertia from a more general model which includes ``inertial'' ... More
A Dynamical Cross-over Regime in the Transmission and Reflection Spectra of Evanescent Waves with 2D Arrays of Josephson JunctionsFeb 18 2013A dynamical cross-over regime is revealed when exposing a classical two-dimensional ordered Josephson junction (JJ) array to evanescent waves and tuning the incident microwave power. At the lowest possible temperature for these experiments, 1.1 K, and ... More
The invariant factor of the chiral determinantJul 10 2008The coupling of spin 0 and spin 1 external fields to Dirac fermions defines a theory which displays gauge chiral symmetry. Quantum mechanically, functional integration of the fermions yields the determinant of the Dirac operator, known as the chiral determinant. ... More
Derivative expansion for the effective action of chiral gauge fermions. The abnormal parity componentDec 19 2000Mar 01 2001Explicit exact formulas are presented, for the leading order term in a strict chiral covariant derivative expansion, for the abnormal parity component of the effective action of two- and four-dimensional Dirac fermions in presence of scalar, pseudo-scalar, ... More
Representation of Complex ProbabilitiesJul 19 1996Let a ``complex probability'' be a normalizable complex distribution $P(x)$ defined on $\R^D$. A real and positive probability distribution $p(z)$, defined on the complex plane $\C^D$, is said to be a positive representation of $P(x)$ if $\langle Q(x)\rangle_P ... More
Gibbs sampling of complex valued distributionsOct 30 2015Sep 26 2016A new technique is explored for the Monte Carlo sampling of complex-valued distributions. The method is based on a heat bath approach where the conditional probability is replaced by a positive representation of it on the complex plane. Efficient ways ... More
Existence of positive representations for complex weightsJun 29 2007The necessity of computing integrals with complex weights over manifolds with a large number of dimensions, e.g., in some field theoretical settings, poses a problem for the use of Monte Carlo techniques. Here it is shown that very general complex weight ... More
Derivative expansion for the effective action of chiral gauge fermions. The normal parity componentDec 19 2000Mar 01 2001Explicit exact formulas are presented, up to fourth order in a strict chiral covariant derivative expansion, for the normal parity component of the Euclidean effective action of even-dimensional Dirac fermions. The bosonic background fields considered ... More
Parity breaking in 2+1 dimensions and finite temperatureFeb 11 1998Mar 17 1999An expansion in the number of spatial covariant derivatives is carried out to compute the $\zeta$-function regularized effective action of 2+1-dimensional fermions at finite temperature in an arbitrary non-Abelian background. The real and imaginary parts ... More
Absence of classical and quantum mixingSep 15 1995It is shown, under mild assumptions, that classical degrees of freedom dynamically coupled to quantum ones do not inherit their quantum fluctuations. It is further shown that, if the assumptions are strengthen by imposing the existence of a canonical ... More
On compositions of d.c. functions and mappingsJun 05 2007A d.c. (delta-convex) function on a normed linear space is a function representable as a difference of two continuous convex functions. We show that an infinite dimensional analogue of Hartman's theorem on stability of d.c. functions under compositions ... More
Constraints on star formation theories from the Serpens molecular cloud and protoclusterJul 10 2002We have mapped the large-scale structure of the Serpens cloud core using moderately optically thick (13CO(1--0) and CS(2--1)) and optically thin tracers (C18O(1--0), C34S(2--1), and N2H+(1--0)), using the 16-element focal plane array operating at a wavelength ... More
Bounds on the Quenched Pressure and Main Eigenvalue of the Ruelle Operator for Brownian Type PotentialsMar 02 2016Jun 23 2016In this paper we consider a random potential derived from the Brownian motion. We obtain upper and lower bounds for the expected value of the main eigenvalue of the associated Ruelle operator and for its quenched topological pressure. We also exhibit ... More
Optical Calibration For Jefferson Lab HKS SpectrometerNov 04 2005In order to accept very forward angle scattering particles, Jefferson Lab HKS experiment uses an on-target zero degree dipole magnet. The usual spectrometer optics calibration procedure has to be modified due to this on-target field. This paper describes ... More
An alternative approach to the static spherically symmetric vacuum global solution to the Einstein's equationsJun 19 2018Sep 12 2018We propose an alternative description of the Schwarzschild black hole based on the requirement that the solution be static not only outside the horizon but also inside it. As a consequence of this assumption, we are led to a change of signature implying ... More
Population Models With Delay in Dynamic EnvironmentJan 05 2006Mar 15 2006We study the combined effects of periodically varying carrying capacity and survival rates on the fish population in the ocean (sea). We introduce the Getz type delay differential equation model with a control parameter which describes how fish are harvested. ... More
Skew braces and the Yang-Baxter equationNov 10 2015Mar 16 2016Braces were introduced by Rump to study non-degenerate involutive set-theoretic solutions of the Yang-Baxter equation. We generalize Rump's braces to the non-commutative setting and use this new structure to study not necessarily involutive non-degenerate ... More
Fermion Scattering off a CP-violating Bubble Wall in the Background of a Uniform Magnetic FieldSep 03 2004In the scenario of the electroweak baryogenesis we consider the dynamics of fermions with a spatially varying mass in presence of a CP-violating bubble wall and a uniform magnetic field perpendicular to the wall. The relevant quantity for baryogenesis, ... More
Langevin spin dynamics based on ab initio calculations: numerical schemes and applicationsJan 30 2014May 22 2014A method is proposed to study the finite-temperature behaviour of small magnetic clusters based on solving the stochastic Landau-Lifshitz-Gilbert equations, where the effective magnetic field is calculated directly during the solution of the dynamical ... More
Scanning Gate Spectroscopy on NanoclustersDec 09 1999A gated probe for scanning tunnelling microscopy (STM) has been developed. The probe extends normal STM operations by means of an additional electrode fabricated next to the tunnelling tip. The extra electrode does not make contact with the sample and ... More
Classification of 6-dimensional real Drinfeld doublesFeb 21 2002Mar 27 2002Starting from the classification of real Manin triples done in a previous paper we look for those that are isomorphic as 6-dimensional Lie algebras with the ad-invariant form used for construction of the Manin triples. We use several invariants of the ... More
Poisson-Lie T-plurality of three-dimensional conformally invariant sigma modelsMar 16 2004May 18 2004Starting from the classification of 6-dimensional Drinfeld doubles and their decomposition into Manin triples we construct 3-dimensional Poisson-Lie T-dual or more precisely T-plural sigma models. Of special interest are those that are conformally invariant. ... More
Reply to Comment on "Statistical mechanics of developable ribbons"Nov 09 2011Starostin and van der Heijden [arXiv:1111.2029] question the validity of the results reported in our Letter [Phys. Rev. Lett. 104, 238104 (2010)] regarding the existence of spontaneous helical structure in finite-temperature developable ribbons. According ... More
Multistability of free spontaneously-curved anisotropic stripsApr 20 2011Dec 07 2011Multistable structures are objects with more than one stable conformation, exemplified by the simple switch. Continuum versions are often elastic composite plates or shells, such as the common measuring tape or the slap bracelet, both of which exhibit ... More
Results on D+-->lv and Ds+-->lv decays at Charm factoryMay 07 2013Jun 07 2013In this article, we reviewed the results on D+-->lv and Ds+-->lv decays at Charm factory.
Wireless Josephson Junction Arrays as Tunable Metamaterials: Inducing Discrete Frequency Steps with Microwave RadiationJan 23 2015We report low temperature, microwave transmission measurements on a new switchable and tunable class of nonlinear metamaterials. A wireless two dimensional array of Josephson junctions (JJ) is probed as a metamaterial where each plaquette in the array ... More
Covariant derivative expansion of the heat kernelSep 14 2004Nov 02 2004Using the technique of labeled operators, compact explicit expressions are given for all traced heat kernel coefficients containing zero, two, four and six covariant derivatives, and for diagonal coefficients with zero, two and four derivatives. The results ... More
The method of covariant symbols in curved space-timeJun 08 2006Sep 11 2006Diagonal matrix elements of pseudodifferential operators are needed in order to compute effective Lagrangians and currents. For this purpose the method of symbols is often used, which however lacks manifest covariance. In this work the method of covariant ... More
On the cascade approach to the quantum multiscattering problemMay 17 2002Sep 04 2002The multiscattering problem is studied in the matrix density formalism. We study how to isolate the quasi-classical degrees of freedom in order to connect with a cascade approach. The different problems that arise, as well as their possible solutions, ... More
Temperature dependence of the anomalous effective action of fermions in two and four dimensionsJul 29 1998Oct 05 1998The temperature dependence of the anomalous sector of the effective action of fermions coupled to external gauge and pseudo-scalar fields is computed at leading order in an expansion in the number of Lorentz indices in two and four dimensions. The calculation ... More
VZ Velorum: 116 years of a Mira starJun 01 2006Using the Harvard College Observatory Photographic Plate Collection and recent CCD observations by the ASAS project we have reconstructed the light variations of the southern pulsating red giant star VZ Velorum between 1890 and early 2006. Contrary to ... More
On the topology of nearly-integrable Hamiltonians at simple resonancesJul 22 2019We show that, in general, averaging at simple resonances a real--analytic, nearly--integrable Hamiltonian, one obtains a one--dimensional system with a cosine--like potential; ``in general'' means for a generic class of holomorphic perturbations and apart ... More
A first look at blazars with BeppoSAXApr 09 1998I describe a general framework that could allow to understand the broad band spectra of blazars and lead to a unified picture of the emission from relativistic jets, in BL Lac objects as well as in flat spectrum, radio loud Quasars. The scheme serves ... More
Polar optical phonon states and their dispersive spectra of a wurtzite nitride superlattice with complex bases: transfer-matrix methodJun 25 2011Based on the dielectric continuum model and transfer-matrix method, the completing polar optical phonon states in a wurtzite GaN-based superlattice (SLs) with arbitrary-layer complex bases are investigated. It is proved that $2^n$ types of phonon modes ... More
Comment on "Weak value amplification is suboptimal for estimation and detection"Feb 02 2014The assumptions of Ferrie and Combes are irrelevant for realistic experimental situations. This undermines their conclusions.
The Reality in Bohmian Quantum Mechanics or Can You Kill with an Empty Wave Bullet?Dec 31 2003Several situations, in which an empty wave causes an observable effect, are reviewed. They include an experiment showing ``surrealistic trajectories'' proposed by Englert et al. and protective measurement of the density of the quantum state. Conditions ... More
Teleportation: Dream or Reality?Oct 29 1998Since its discovery in 1993, we witness an intensive theoretical and experimental effort centered on teleportation. Very recently it was claimed in the press that ``quantum teleportation has been achieved in the laboratory'' (T. Sudbery, Nature, 390, ... More
Holomorphic extension from the sphere to the ballNov 13 2009Real analytic functions on the boundary of the sphere which have separate holomorphic extension along the complex lines through a boundary point have holomorphic extension to the ball. This was proved in a previous preprint by an argument of CR geometry. ... More
Extensions of set-theoretic solutions of the Yang-Baxter equation and a conjecture of Gateva-IvanovaFeb 03 2015Oct 16 2015We develop a theory of extensions for involutive and nondegenerate solutions of the set-theoretic Yang-Baxter equation and use it to produce new families of solutions. As an application we construct an infinite family of counterexamples to a conjecture ... More
Flow Phase Diagram for the Helium SuperfluidsFeb 11 2004The flow phase diagram for He II and $^3$He-B is established and discussed based on available experimental data and the theory of Volovik [JETP Letters {\bf{78}} (2003) 553]. The effective temperature - dependent but scale - independent Reynolds number ... More
Cosmology with Gamma-Ray BurstsAug 10 2009Gamma-Ray Bursts (GRBs) are the brightest sources in the universe, emit mostly in the hard X-ray energy band and have been detected at redshifts up to ~8.1. Thus, they are in principle very powerful probes for cosmology. I shortly review the researches ... More
Swift GRBs and the Ep,i - Eiso correlationNov 06 2006Jan 22 2007The Ep,i - Eiso correlation is one of the most intriguing and debated observational evidences in Gamma-Ray Bursts (GRB) astrophysics. Swift, with its high sensitivity and fast pointing capabilities, is reducing a lot the impact of selection effects in ... More
A low density of the Extragalactic Background Light revealed by the H.E.S.S. spectra of the BLLac objects 1ES 1101-232 and H 2356-309Dec 23 2006The unexpectedly hard spectra measured by HESS for the BLLacs 1ES 1101-232 and H 2356-309 has allowed an upper limit on the Extragalactic Background Light (EBL) to be derived in the optical/near-infrared range, which is very close to the lower limit given ... More
The oscillating behavior of the pair correlation function in galaxiesJan 28 2014The pair correlation function (PCF) for galaxies presents typical oscillations in the range 20-200 Mpc/h which are named baryon acoustic oscillation (BAO). We first review and test the oscillations of the PCF when the 2D/3D vertexes of the Poissonian ... More
A classical and a relativistic law of motion for spherical supernovaeOct 20 2014In this paper we derive some first order differential equations which model the classical and the relativistic thin layer approximations. The circumstellar medium is assumed to follow a density profile of Plummer type, or of Lane--Emden ($n=5$) type, ... More
The relativistic three dimensional evolution of SN 1987AMay 27 2014The high velocities observed in supernovae require a relativistic treatment for the equation of motion in the presence of gradients in the density of the interstellar medium. The adopted theory is that of the thin layer approximation. The chosen medium ... More
Padé Approximant and Minimax Rational Approximation in Standard CosmologyFeb 20 2016The luminosity distance in the standard cosmology as given by $\Lambda$CDM and consequently the distance modulus for supernovae can be defined by the Pad\'e approximant. A comparison with a known analytical solution shows that the Pad\'e approximant for ... More
The instanton contributions to Yang-Mills theory on the torus: localization, Wilson loops and the perturbative expansionNov 05 1998The instanton contributions to the partition function and to homologically trivial Wilson loops for a U(N) Yang-Mills theory on a torus $T^2$ are analyzed. An exact expression for the partition function is obtained as a sum of contributions localized ... More
Optimal sequence for Parrondo gamesSep 23 2014An algorithm based on backward induction is devised in order to compute the optimal sequence of games to be played in Parrondo games. The algorithm can be used to find the optimal sequence for any finite number of turns or in the steady state, showing ... More
Constant Dilaton Vacua and Kinks in 2D (Super-)GravitySep 23 2005Dec 06 20052D dilaton (super-)gravity contains a special class of solutions with constant dilaton, a kink-like solution connecting two of them was recently found in a specific model that corresponds to the KK reduced 3D Chern-Simons term. Here we develop the systematics ... More
Quantum dilaton supergravity in 2D with non-minimally coupled matterAug 30 2004General N=(1,1) dilaton supergravity in two dimensions allows a background independent exact quantization of the geometric part, if these theories are formulated as specific graded Poisson-sigma models. In this work the extension of earlier results to ... More
Generalized transformation optics from triple spacetime metamaterialsJul 01 2008Oct 27 2008In this paper various extensions of the design strategy of transformation media are proposed. We show that it is possible to assign different transformed spaces to the field strength tensor (electric field and magnetic induction) and to the excitation ... More
Dynamics of Glue-Balls in N=1 SYM TheoryOct 06 2003The extension of the Veneziano-Yankielowicz effective Lagrangian with terms including covariant derivatives is discussed. This extension is important to understand glue-ball dynamics of the theory. Though the superpotential remains unchanged, the physical ... More
Unveiling the hidden AGN in the merging starburst system ARP 299 (IC694 + NGC 3690)Dec 18 2002As part of a research of elusive AGN in a well defined sample of infrared selected galaxies (using BeppoSAX, Chandra, XMM-Newton and INTEGRAL data) we have observed with BeppoSAX the merging starburst system Arp 299. The broad-band (0.1-40 keV) coverage ... More
String Theory and the Principle of Black Hole ComplementarityJul 27 1993String theory provides an example of the kind of apparent inconsistency that the {\it Principle of Black Hole Complementarity\/} deals with. To a freely infalling observer a string falling through a black hole horizon appears to be a Planck size object. ... More
OCD factorization for the pion diffractive dissociation into two jetsSep 10 2001We present main ideas and obtained results of our recent calculations of Coulomb and QCD contribution to the pion diffractive dissociation into two jets.