Results for "A. Giribono"

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Electron beam transfer line design for plasma driven Free Electron LasersMar 01 2018Plasma driven particle accelerators represent the future of compact accelerating machines and Free Electron Lasers are going to benefit from these new technologies. One of the main issue of this new approach to FEL machines is the design of the transfer ... More
Plasma boosted electron beams for driving Free Electron LasersFeb 19 2018In this paper, we report results of simulations, in the framework of both EuPRAXIA \cite{Walk2017} and EuPRAXIA@SPARC\_LAB \cite{Ferr2017} projects, aimed at delivering a high brightness electron bunch for driving a Free Electron Laser (FEL) by employing ... More
Energy Measurements by Means of Transition Radiation in novel LinacsFeb 12 2018Advanced linear accelerator design may use Optical Transition Radiation (OTR) screens to measure beam spot size; for instance, such screens are foreseen in plasma based accelerators (EuPRAXIA@SPARC_LAB) or Compton machines (Gamma Beam Source@ELI-NP). ... More
EuPRAXIA@SPARC_LAB: the high-brightness RF photo-injector layout proposalFeb 25 2018At EuPRAXIA@SPARC_LAB, the unique combination of an advanced high-brightness RF injector and a plasma-based accelerator will drive a new multi-disciplinary user-facility. The facility, that is currently under study at INFN-LNF Laboratories (Frascati, ... More
RF injector design studies for the trailing witness bunch for a plasma-based user facilityJan 09 2018Jan 16 2018The interest in plasma-based accelerators as drivers of user facilities is growing worldwide thanks to its compactness and reduced costs. In this context the EuPRAXIA collaboration is preparing a conceptual design report for a multi-GeV plasma-based accelerator ... More
EUPRAXIA@SPARC_LAB: Beam Dynamics studies for the X-band LinacJan 30 2018In the framework of the Eupraxia Design Study an advanced accelerator facility EUPRAXIA@SPARC_LAB has been proposed to be realized at Frascati (Italy) Laboratories of INFN. Two advanced acceleration schemes will be applied, namely an ultimate high gradient ... More
Preliminary RF design of an X-band linac for the EuPRAXIA@SPARC_LAB projectJan 02 2018In the framework of the upgrade of the SPARC_LAB facility at INFN-LNF, named EuPRAXIA@SPARC_LAB, a high gradient linac is foreseen. One of the most suitable options is to realize it in X-band. A preliminary design study of both accelerating structures ... More
Positron driven muon source for a muon colliderMay 14 2019May 19 2019The design of a future multi-TeV muon collider needs new ideas to overcome the technological challenges related to muon production, cooling, accumulation and acceleration. In this paper a layout of a positron driven muon source known as the Low EMittance ... More
Conceptual design of electron beam diagnostics for high brightness plasma acceleratorFeb 14 2018A design study of the diagnostics of a high brightness linac, based on X-band structures, and a plasma accelerator stage, has been delivered in the framework of the EuPRAXIA@SPARC_LAB project. In this paper, we present a conceptual design of the proposed ... More
Longitudinal phase-space manipulation with beam-driven plasma wakefieldsFeb 21 2019The development of compact accelerator facilities providing high-brightness beams is one of the most challenging tasks in field of next-generation compact and cost affordable particle accelerators, to be used in many fields for industrial, medical and ... More
Overview of Plasma Lens Experiments and Recent Results at SPARC_LABFeb 01 2018Beam injection and extraction from a plasma module is still one of the crucial aspects to solve in order to produce high quality electron beams with a plasma accelerator. Proper matching conditions require to focus the incoming high brightness beam down ... More
Nano-machining, surface analysis and emittance measurements of a copper photocathode at SPARC_LABJan 11 2018R\&D activity on Cu photocathodes is under development at the SPARC\_LAB test facility to fully characterize each stage of the photocathode "life" and to have a complete overview of the photoemission properties in high brightness photo-injectors. The ... More
Recent results at SPARC_LABJan 18 2018The current activity of the SPARC_LAB test-facility is focused on the realization of plasma-based acceleration experiments with the aim to provide accelerating field of the order of several GV/m while maintaining the overall quality (in terms of energy ... More
Positron driven muon source for a muon colliderMay 14 2019The design of a future multi-TeV muon collider needs new ideas to overcome the technological challenges related to muon production, cooling, accumulation and acceleration. In this paper a layout of a positron driven muon source known as the Low EMittance ... More
Simulation design for forthcoming high quality plasma wakefield acceleration experiment in linear regime at SPARC_LABFeb 14 2018In the context of plasma wakefield acceleration beam driven, we exploit a high density charge trailing bunch whose self-fields act by mitigating the energy spread increase via beam loading compensation, together with bunch self-contain operated by the ... More
EuPRAXIA@SPARC_LAB Design study towards a compact FEL facility at LNFJan 26 2018On the wake of the results obtained so far at the SPARC\_LAB test-facility at the Laboratori Nazionali di Frascati (Italy), we are currently investigating the possibility to design and build a new multi-disciplinary user-facility, equipped with a soft ... More
The Compact Linear Collider (CLIC) - 2018 Summary ReportDec 14 2018May 06 2019The Compact Linear Collider (CLIC) is a TeV-scale high-luminosity linear $e^+e^-$ collider under development at CERN. Following the CLIC conceptual design published in 2012, this report provides an overview of the CLIC project, its current status, and ... More
Curved space resolution of singularity of fractional D3-branes on conifoldNov 01 2001We construct a supergravity dual to the cascading $SU(N+M) x SU(N)$ supersymmetric gauge theory (related to fractional D3-branes on conifold according to Klebanov et al) in the case when the 3-space is compactified on $S^3$ and in the phase with unbroken ... More
Schwinger-Dyson approach and its application to generate a light composite scalarJan 15 2016Feb 24 2016We discuss the possibility of generating a light composite scalar boson, in a scenario that we may generically call Technicolor, or in any variation of a strongly interacting theory, where by light we mean a scalar composite mass about one order of magnitude ... More
Dynamical gluon mass corrections in heavy quarkonia decaysApr 26 2000Using the expression of the dynamical gluon mass obtained through the operator product expansion we discuss the relevance of gluon mass effects in the decays V -> hadrons (V = J/Psi, Upsilon). Relativistic and radiative corrections are also introduced ... More
Semiclassical rigid strings with two spins in AdS_5Nov 12 2009Semiclassical spinning string states in AdS_5 are, in general, characterised by the three SO(2,4) conserved charges: the energy E and the two spins S_1 and S_2. We discuss several examples of explicit classical solutions for rigid closed strings of (bended) ... More
Search for excited electrons through $γγ$ scatteringAug 10 2012We study the potential of $\gamma \gamma$ option of future high energy linear $e^{+}e^{-}$ colliders to search for excited electrons with spin-1/2. We calculate single production cross sections, give the angular distributions and $f-m^*$ contour plots ... More
A study of spectra of Cyg X-3 observed by BeppoSAXDec 22 2004Jan 10 2005We model the ~1-200 keV spectra of Cygnus X-3 observed by BeppoSAX. The continuum, modeled by Comptonization in a hybrid plasma, is modified by the strongly ionized plasma of the stellar wind of the Wolf-Rayet companion star. Discrete absorption and emission ... More
Quantum Corrections to Bekenstein-Hawking Black Hole Entropy and Gravity Partition FunctionsApr 25 2013Algebraic aspects of the computation of partition functions for quantum gravity and black holes in $AdS_3$ are discussed. We compute the sub-leading quantum corrections to the Bekenstein-Hawking entropy. It is shown that the quantum corrections to the ... More
Chiral expansion of nucleon PDF at $x\sim m_π/M_N$Nov 14 2013Based on the chiral perturbation theory, we investigate the low-energy dynamics of nucleon parton distributions. We show that in different regions of the momentum fraction $x$ the chiral expansion is significantly different. For nucleon parton distributions ... More
Can Electro-Weak $\h$-Term be Observable ?May 14 1993We rederive and discuss the result of the previous paper that in the standard model $\theta$-term related to $W$-boson field can not be induced by weak instantons. This follows from the existence of the fermion zero mode in the instanton field even when ... More
Optimized perturbation theory for bound states: toy model and realistic problemJun 20 1995Within quantum mechanics model we study the problem of resummation of an asymptotic perturbation series for bound state parameters via optimization of the perturbative expansion. A possible application of the method to the positronium lifetime calculation ... More
A study of RXTE and BeppoSAX observations of Cyg X-3Jan 14 2004We present an analysis of Cyg X-3 data from RXTE/PCA,HEXTE and ASM, supplemented by a selected spectrum from BeppoSAX. We fit the PCA/HEXTE spectra from 1996-2000 by a model including hybrid Comptonization, reflection and absorption, and classify them ... More
Non-reciprocal quantum interactions and devices via autonomous feed-forwardOct 20 2016In a recent work [A. Metelmann and A. A. Clerk, Phys. Rev. X 5, 021025 (2015)], a general reservoir-engineering approach for generating non-reciprocal quantum interactions and devices was described. We show here how in many cases this general recipe can ... More
Deciphering the minimum of energy of some walking technicolor modelsMay 11 2010There are quasi-conformal theories, like the Minimal and Ultraminimal Technicolor models, which may break dynamically the gauge symmetry of the Standard Model and at the same time are compatible with electroweak precision data. The main characteristic ... More
Strength of the Trilinear Higgs Boson Coupling in Technicolor ModelsOct 14 2005Oct 20 2005We discuss the strength of the trilinear Higgs boson coupling in technicolor (or composite) models in a model independent way. The coupling is determined as a function of a very general ansatz for the technicolor self-energy, and turns out to be equal ... More
Scalar bosons in Minimal and Ultraminimal Technicolor: Masses, trilinear couplings and widthsDec 05 2009May 04 2010We compute masses, trilinear self-couplings and decay widths into weak bosons of the scalar composite bosons in the case of the Minimal and Ultraminimal technicolor models. The masses, computed via the Bethe-Salpeter equation, turn out to be light and ... More
Graph homology: Koszul and Verdier dualityFeb 12 2007We show that Verdier duality for certain sheaves on the moduli spaces of graphs associated to Koszul operads corresponds to Koszul duality of operads. This in particular gives a conceptual explanation of the appearance of graph cohomology of both the ... More
Top quark threshold production in $γγ$ collision in the next-to-leading orderOct 27 1998Apr 23 1999The total cross section of the top quark-antiquark pair production near threshold in $\gamma\gamma$ collision is computed analytically up to the next-to-leading order in perturbative and nonrelativistic expansion for general photon helicity. The approximation ... More
On a subtle point of sum rules calculations: toy modelMar 30 1995We consider a two-point correlator in massless $\phi^3$ model within the ladder approximation . The spectral density of the correlator is known explicitly and does not contain any resonances. Meanwhile making use of the standard sum rules technique with ... More
Semiclassical strings in AdS_5 x S^5 and scalar operators in N=4 SYM theoryJul 26 2004Sep 14 2004We review recent progress in checking AdS/CFT duality in the sector of ''semiclassical'' string states dual to ''long'' scalar operators of N=4 super Yang-Mills theory. In particular, we discuss the effective action approach, in which the same sigma model ... More
Interactions Between Branes and Matrix TheoriesSep 16 1997Oct 06 1997We review some tests of the 0-brane and instanton matrix models based on comparing long-distance interaction potentials between branes and their bound states (with 1/2,1/4 or 1/8 of supersymmetry) in supergravity and in super Yang-Mills descriptions. ... More
No-force condition and BPS combinations of p-branes in 11 and 10 dimensionsSep 26 1996Dec 05 1996The condition of vanishing of static force on a q-brane probe in the gravitational background produced by another p-brane is used to give a simple derivation of the pair-wise intersection rules which govern the construction of BPS combinations of branes. ... More
On singularities of spherically symmetric backgrounds in string theorySep 08 1995We suggest that for singular rotationally invariant closed string backgrounds which need sources for their support at the origin (in particular, for special plane waves and fundamental strings) certain `trivial' \a'-corrections (which are usually ignored ... More
Closed strings in uniform magnetic field backgroundsMay 23 1995We consider a class of conformal models describing closed strings in axially symmetric stationary magnetic flux tube backgrounds. These models are closed string analogs of the Landau model of a particle in a magnetic field or the model of an open string ... More
String cosmology and dilatonJun 17 1992We discuss some aspects of string cosmology with an emphasis on the role played by the dilaton. A cosmological scenario based on the assumption that all spatial dimensions are periodic so that winding modes play an important role is reviewed. A possibility ... More
On limits of superstring in AdS_5 x S^5Jan 15 2002Jan 16 2002The superstring action in AdS_5 x S^5 depends on two parameters: the inverse string tension a' and the radius R. The standard AdS/CFT correspondence requires that the string coordinates are rescaled so that the action depends only on one combination of ... More
Harmonic superpositions of M-branesApr 07 1996Jun 05 1996We present solutions describing supersymmetric configurations of 2 or 3 orthogonally intersecting 2-branes and 5-branes of D=11 supergravity. The configurations which preserve 1/4 or 1/8 of maximal supersymmetry are 2+2, 5+5, 2+5, 2+2+2, 5+5+5, 2+2+5 ... More
Generalised chiral null models and rotating string backgroundsMar 15 1996We consider an extension of a special class of conformal sigma models (`chiral null models') which describe extreme supersymmetric string solutions. The new models contain both `left' and `right' vector couplings and should correspond to non-BPS backgrounds. ... More
Dilaton, winding modes and cosmological solutionsDec 03 1991We review some formal aspects of cosmological solutions in closed string theory with duality symmetric ``matter'' following recent paper with C. Vafa (HUTP-91/A049). We consider two models : when the matter action is the classical action of the fields ... More
On the Recent Results of E835 Experiment at FNALNov 28 2003Feb 06 2004In this note we briefly concern several recent results of E835 Experiment at FNAL that are discussed in the framework of unified picture on hadronic spectra elaborated in our early works. It has been established that new E835 Collaboration results provided ... More
An achromatic polarization retarder realized with slowly varying linear and circular birefringenceMay 02 2011Using the phenomena of linear and circular birefringence we propose a device that can alter general elliptical polarization of a beam by a predetermined amount, thereby allowing conversion between linearly-polarized light and circularly polarized light ... More
Conceptual design of a scalable multi-kton superconducting magnetized liquid Argon TPCOct 11 2005We discuss the possibility of new generation neutrino and astroparticle physics experiments exploiting a superconducting magnetized liquid Argon Time Projection Chamber (LAr TPC). The possibility to complement the features of the LAr TPC with those provided ... More
Ideas for future liquid Argon detectorsSep 13 2004We outline a strategy for future experiments on neutrino and astroparticle physics based on the use, at different detector mass scales (100 ton and 100 kton), of the liquid Argon Time Projection Chamber (LAr TPC) technique. The LAr TPC technology has ... More
Finite Temperature Reduction of the SU(2) Higgs-Model with Complete Static BackgroundMay 31 1994Direct evaluation of the 1-loop fluctuation determinant of non-static degrees of freedom in a complete static background is advocated to be more efficient for the determination of the effective three-dimensional model of the electroweak phase transition ... More
Condensates and instanton - torus knot duality. Hidden Physics at UV scaleDec 29 2014Aug 16 2015We establish the duality between the torus knot superpolynomials or the Poincar\'e polynomials of the Khovanov homology and particular condensates in $\Omega$-deformed 5D supersymmetric QED compactified on a circle with 5d Chern-Simons(CS) term. It is ... More
From Yang-Mills Lagrangian to MHV DiagramsOct 14 2005Jan 18 2006We prove the equivalence of a recently suggested MHV-formalism to the standard Yang-Mills theory. This is achieved by a formally non-local change of variables. In this note we present the explicit formulas while the detailed proofs are postponed to a ... More
Phenomenological Lagrangians, gauge models and branesApr 03 2016May 18 2016Phenomenological Lagrangians for physical systems with spontaneously broken symmetries are reformulated in terms of gauge field theory. Description of the Dirac $p$-branes in terms of the Yang-Mills-Cartan gauge multiplets interacting with gravity, is ... More
On the cancellation of 4-derivative terms in the Volkov-Akulov actionMar 22 2010Sep 01 2010Recently Kuzenko and McCarty observed the cancellation of 4-derivative terms in the $D=4 {\cal N}=1$ Volkov-Akulov supersymmetric action for the fermionic Nambu-Goldstone field. Here is presented a simple algebraic proof of the cancellation based on using ... More
Tension as a Perturbative Parameter in Non--Linear String Equations in Curved Space--TimeJun 04 1996A perturbation theory with respect to tension parameter $\gamma/\alpha^\prime$ for the non--linear equations of string, moving in curved space--time is considered. Obtained are linearized motion equations for the functions of the $n-$th degree of approximation ... More
Gauge theory approach to branes and spontaneous symmetry breakingSep 01 2015Apr 08 2016Gauge theory approach to consideration of the Nambu-Goldstone bosons as gauge and vector fields represented by the Cartan forms of spontaneously broken symmetries, is discussed. The approach is generalized to describe the fundamental branes in terms of ... More
On brane symmetriesSep 23 2014The geometric approach to branes is reformulated in terms of gauge vector fields interacting with massless tensor multiplets in gravitational backgrounds
Gauge fields beyond perturbation theoryOct 30 2013A new formulation of nonabelian gauge theories, introducing new ghost fields and new symmetry is proposed. This formulation does not suffer from Gribov ambiguity and allows to quantize nonabelian gauge fields beyond perturbation theory.
Chiral symmetry in lattice QCDOct 30 2000A chiral invariant effective action for lattice QCD is proposed. Its connection to the multifermion model is established. A possibility of using this action for computer simulations is discussed.
Decoupling of the longitudinal polarization of the vector field in the massless Higgs-Kibble modelMay 28 2012It is shown that the three dimensionally longitudinal component of the vector field decouples in the massless limit of nonabelian Higgs model.
Higgs mechanism as a collective effect due to extra dimensionApr 07 2006A systematic analysis of the unitary electroweak model described by the higher derivative Lagrangian depending on extra dimension [1] is presented.
Gauge invariance of dimension two condensate in Yang-Mills theoryJul 22 2004Gauge independence of dimension two condensate in Yang-Mills theory is demonstrated by using a noncommutative theory technique.
Renormalization by enforcing a symmetryApr 26 2001A new renormalization scheme for theories with nontrivial internal symmetry is proposed. The scheme is regularization independent and respects the symmetry requirements.
Negative longitudinal magnetoresistance in Dirac and Weyl metalsMay 07 2015Jun 29 2015It has recently been found that Dirac and Weyl metals are characterized by an unusual weak-field longitudinal magnetoresistance: large, negative, and quadratic in the magnetic field. This has been shown to arise from chiral anomaly, i.e. nonconservation ... More
Binary life after the AGB - towards a unified pictureDec 15 2006A unified evolutionary scheme that includes post-AGB systems, barium stars, symbiotics, and related systems, explaining their similarites as well as differences. Can we construct it? We compare these various classes of objects in order to construct a ... More
Radius & Distance Estimates of the Isolated Neutron Stars Geminga & PSR B0656+14 using Optical PhotometryDec 10 1998Integrated ground-based and HST optical studies of isolated neutron stars have provided important independent datasets in the determination of emission activity, particularly in the fitting of anticipated Rayleigh-Jeans extrapolations from EUV/soft X-ray ... More
On Lagrangian formulations for mixed-symmetry HS fields on AdS spaces within BFV-BRST approachSep 28 2008Oct 03 2008The key aspects of a gauge-invariant Lagrangian description of massive and massless half-integer higher-spin fields in AdS spaces with a two-row Young tableaux $Y(s_1,s_2)$ are presented in an unconstrained description, as well as in off-shell formulations ... More
General Superfield Quantization Method. III. Construction of Quantization SchemeApr 16 2003Extension procedure for supermanifold ${\cal M}_{cl}$ of superfields ${\cal A}^{\imath}(\theta)$, ghost number construction are considered. Classical and $\hbar$-deformed generating (master) equations, existence theorems for their solutions are formulated ... More
Galactic origin of ultrahigh energy cosmic raysFeb 16 2009The arrival directions of ultrahigh energy extensive air showers (EAS) by Yakutsk, AGASA, P. Auger array data are analyzed. For the first time, the maps of equal exposition of celestial sphere for the distribution of particles by AGASA and P. Auger arrays ... More
Particles Flux of Ultrahigh Energy from a Galactic PlaneJan 16 2012Arrival directions of particles were analyzed according to the arrays of extensive air showers (EAS) data. A new method of sources search and anisotropy of arrival directions particles is suggested. There was found the particles flux of ultrahigh energy ... More
Entropy current for the relativistic Kadanoff-Baym equation and H-theorem in $O(N)$ theory with NLO self-energy of $1/N$ expansionJun 06 2010We derive an expression of the kinetic entropy current in the nonequilibrium $O(N)$ scalar theory from the Schwinger-Dyson (Kadanoff-Baym) equation with the 1st order gradient expansion. We show that our kinetic entropy satisfies the H-theorem for the ... More
Mean Field Renormalization Group for the Boundary Magnetization of Strip ClustersJul 13 1993We analyze in some detail a recently proposed transfer matrix mean field approximation which yields the exact critical point for several two dimensional nearest neighbor Ising models. For the square lattice model we show explicitly that this approximation ... More
A search for exact superstring vacuaAug 23 1993We investigate $2d$ sigma-models with a $2+N$ dimensional Minkowski signature target space metric and Killing symmetry, specifically supersymmetrized, and see under which conditions they might lead to corresponding exact string vacua. It appears that ... More
Topological SemimetalsOct 25 2016Topological semimetals and metals have emerged as a new frontier in the field of quantum materials. Novel macroscopic quantum phenomena they exhibit are not only of fundamental interest, but may hold some potential for technological applications.
The thermodynamics of urban population flowsJun 29 2012Orderliness, reflected via mathematical laws, is encountered in different frameworks involving social groups. Here we show that a thermodynamics can be constructed that macroscopically describes urban population flows. Microscopic dynamic equations and ... More
Scale-invariance underlying the logistic equation and its social applicationsApr 11 2012On the basis of dynamical principles we derive the Logistic Equation (LE), widely employed (among multiple applications) in the simulation of population growth, and demonstrate that scale-invariance and a mean-value constraint are sufficient and necessary ... More
Variational Principle underlying Scale Invariant Social SystemsApr 11 2012MaxEnt's variational principle, in conjunction with Shannon's logarithmic information measure, yields only exponential functional forms in straightforward fashion. In this communication we show how to overcome this limitation via the incorporation, into ... More
On the problem of the interpretation of quantum physicsApr 10 2014Current thinking on the interpretation of quantum physics is reviewed, with special detail given to the Copenhagen and Everett many-worlds interpretations.
Spontaneous breaking of symmetry of the gravitons of the long wave spectrum in the early UniverseMay 07 2009It is shown that nonlinear terms in equations of gravitons on the background of curved space-time of the expanding Universe can solve the problem of the negative square of the effective mass formally arising in linear approximation for gravitons. Similar ... More
Nonzero cosmological constant and the many vacua worldNov 14 2003The idea of the quantum state of the Universe described by some density matrix, i.e mixture of at least two vacua, the trivial symmetric and the nontrivial one with spontaneously broken symmetry is discussed. Nonzero cosmological constant necessarily ... More
Phenomenology of infrared finite gluon propagator and coupling constantOct 19 2006Oct 23 2006We report on some recent solutions of the Dyson-Schwinger equations for the infrared behavior of the gluon propagator and coupling constant, discussing their differences and proposing that these different behaviors can be tested through hadronic phenomenology. ... More
QCD phenomenology with infrared finite SDE solutionsOct 29 2009Recent progress in the solution of Schwinger-Dyson equations (SDE), as well as lattice simulation of pure glue QCD, indicate that the gluon propagator and coupling constant are infrared (IR) finite. We discuss how this non-perturbative information can ... More
Glueballs in Peripheral Heavy-Ion CollisionsSep 12 1995We estimate the cross-section for glueball production in peripheral heavy-ion collisions through two-photon and double-Pomeron exchange, at energies that will be available at RHIC and LHC. Glueballs will be produced at large rates, opening the possibility ... More
On the Charged Bose LiquidOct 31 1997A new approach developed by A. Shanenko [Phys. Lett. A 227 (1997) 367] for investigating the spatial boson correlations at low temperatures is considered in the particular case of the Coulomb interaction potential. This approach is based on integro-differential ... More
On Pair-Particle Distribution in Imperfect Bose GasDec 20 1996A simple model of estimating the radial distribution function of an imperfect Bose gas in the ground state is presented. The model is based on integro-differential equations derived by considering the space boson distribution in an external field. With ... More
The effects of stellar winds and magnetic fields on exoplanetsOct 02 2013The great majority of exoplanets discovered so far are orbiting cool, low-mass stars whose properties are relatively similar to the Sun. However, the stellar magnetism of these stars can be significantly different from the solar one, both in topology ... More
Qualitative properties of scalar-tensor theories of GravityOct 21 1999The qualitative properties of spatially homogeneous stiff perfect fluid and minimally coupled massless scalar field models within general relativity are discussed. Consequently, by exploiting the formal equivalence under conformal transformations and ... More
Kinematic Self-SimilarityOct 25 1996Self-similarity in general relativity is briefly reviewed and the differences between self-similarity of the first kind and generalized self-similarity are discussed. The covariant notion of a kinematic self-similarity in the context of relativistic fluid ... More
Self-Similar Dynamical Relaxation of Dark Matter Halos in an Expanding UniverseOct 26 2011Nov 14 2011We investigate the structure of cold dark matter halos using advanced models of spherical collapse and accretion in an expanding Universe. These base on solving time-dependent equations for the moments of the phase-space distribution function in the fluid ... More
How entangled can two couples get?May 02 2000Jul 15 2000We describe a pure state of four qubits whose single-qubit density matrices are all maximally mixed and whose average entanglement as a system of two pairs of qubits appears to be maximal.
Fluid-solid phase-separation in hard-sphere mixtures is unrelated to bond-percolationJan 18 2000In a recent letter, Buhot proposes that entropy driven phase-separation in hard-core binary mixtures is directly related to a bond-percolation transition. However, at least for binary hard-sphere mixtures, calculations based on an accurate approximation ... More
On the viability of gravitational Bose-Einstein condensates as alternatives to supermassive black holesSep 17 2011Sep 20 2011Black holes are inevitable mathematical outcome of spacetime-energy coupling in general relativity. Currently these objects are of vital importance for understanding numerous phenomena in astrophysics and cosmology. However, neither theory nor observations ... More
Cation Transport in Polymer Electrolytes: A Microscopic ApproachMar 08 2007May 11 2007A microscopic theory for cation diffusion in polymer electrolytes is presented. Based on a thorough analysis of molecular dynamics simulations on PEO with LiBF$_4$ the mechanisms of cation dynamics are characterised. Cation jumps between polymer chains ... More
1/4-BPS states on noncommutative toriJul 02 1999Aug 06 1999We give an explicit expression for classical 1/4-BPS fields in supersymmetric Yang-Mills theory on noncommutative tori. We use it to study quantum 1/4-BPS states. In particular we calculate the degeneracy of 1/4-BPS energy levels.
Full hamiltonian structure for a parametric coupled Korteweg-de Vries systemSep 08 2014We obtain the full hamiltonian structure for a parametric coupled KdV system. The coupled system arises from four different real basic lagrangians. The associated hamiltonian functionals and the corresponding Poisson structures follow from the geometry ... More
Hamiltonian structure of an operator valued extension of Super KdV equationsJul 29 2014An extension of the super Korteweg-de Vries integrable system in terms of operator valued functions is obtained. In particular the extension contains the $N=1$ Super KdV and coupled systems with functions valued on a symplectic space. We introduce a Miura ... More
The Hamiltonian structure of a coupled system derived from a supersymmetric breaking of Super KdV equationsJun 03 2013A supersymmetric breaking procedure for $N=1$ Super KdV, using a Clifford algebra, is implemented. Dirac's method for the determination of constraints is used to obtain the Hamiltonian structure, via a Lagrangian, for the resulting solitonic system of ... More
The Vorticity of Solar Photospheric Flows on the Scale of GranulationJun 04 2016We employ time sequences of images observed with a G-band filter (4305{\AA}) by the Solar Optical Telescope (SOT) on board of Hinode spacecraft at different latitude along solar central me-ridian to study vorticity of granular flows in quiet Sun areas ... More
Dual oscillators and Quantum Pendulums: spectrum and correlatorsMar 06 2007Jun 04 2007We outline the nonlinear transformation in the path integral representation for partition function of O(N) symmetric oscillator systems bringing their duality to certain one-dimensional oscillators with unstable potential shapes. This duality transformation ... More
On The Inhomogeneous Quantum GroupsAug 10 1994Sep 22 1994Using the multi-parametric deformation of the algebra of functions on $ \GL{n+1} $ and the universal enveloping algebra $ \U{\igl{n+1}} $, we construct the multi-parametric quantum groups $ \IGLq{n} $ and $ \Uq{\igl{n}} $.