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July 2002 arXiv papers — page 11

Showing 1,001–1,100 of 3,203 papers

  1. G. Blumberg, A. Koitzsch, A. Gozar, B. S. Dennis

    We confirm that all the results of scanning SQUID, tunneling, ARPES, penetration depth and Raman experiments are consistent with a nonmonotonic d_{x^2-y^2} superconducting order parameter proposed in Phys. Rev. Lett., 88, 107002 (2002).

  2. C. Macesanu, C. D. McMullen, S. Nandi

    In the universal extra dimensions (UED) scenario, the tree level masses of the first level Kaluza-Klein (KK) excitations of Standard Model particles are essentially degenerate. Radiative corrections will, however, lift this degeneracy, allowing the first level excitations to decay to the lightest KK particle (LKP), which is the gamma^*. KK number conservatio

  3. Marc S. Seigar

    We have obtained ground-based I, J and K band images of the spiral galaxy, Messier 74 (NGC 628). This galaxy has been shown to possess a circumnuclear ring of star formation from both near-infrared spectroscopy of CO absorption and sub-millimetre imaging of CO emission. Circumnuclear rings of star formation are believed to exist only as a result of a bar pot

  4. H. Liu, Ch. Elster, W. Gloeckle

    The Faddeev equations for the three-body bound state with two- and three-body forces are solved directly as three-dimensional integral equation. The numerical feasibility and stability of the algorithm, which does not employ partial wave decomposition is demonstrated. The three-body binding energy and the full wave function are calculated with Malfliet-Tjon-

  5. Yoshio Kikukawa, Yoichi Nakayama

    Two-dimensional N=2 Wess-Zumino model is constructed on the lattice through Nicolai mapping with Ginsparg-Wilson fermion. The Nicolai mapping requires a certain would-be surface term in the bosonic action which ensures the vacuum energy cancellation even on the lattice, but inevitably breaks chiral symmetry. With the Ginsparg-Wilson fermion, the holomorphic

  6. Pedro L. del Angel, Stefan Müller-Stach

    This paper continues our previous work done in math.AG/0008207 and is an attempt to establish a conceptual framework which generalizes the work of Manin on the relation between non-linear second order ODEs of type Painleve VI and integrable systems. The principle behind everything is a strong interaction between K-theory and Picard-Fuchs type differential eq

  7. Radu Ionicioiu, Irene D'Amico

    Spin preparation and spin detection are fundamental problems in spintronics and in several solid state proposals for quantum information processing. Here we propose the mesoscopic equivalent of an optical polarizing beam splitter (PBS). This interferometric device uses non-dispersive phases (Aharonov-Bohm and Rashba) in order to separate spin up and spin dow

  8. F. Lesage, P. Mathieu, J. Rasmussen, H. Saleur

    The bosonic beta-gamma ghost system has long been used in formal constructions of conformal field theory. It has become important in its own right in the last few years, as a building block of field theory approaches to disordered systems, and as a simple representative -- due in part to its underlying su(2)_{-1/2} structure -- of non-unitary conformal field

  9. D. R. Grempel, Qimiao Si

    We report the first numerical identification of a locally quantum critical point, at which the criticality of the local Kondo physics is embedded in that associated with a magnetic ordering. We are able to numerically access the quantum critical behavior by focusing on a Kondo-lattice model with Ising anisotropy. We also establish that the critical exponent

  10. Arne Rau, Jochen Greiner

    We present a comprehensive X-ray study of four years of pointed RXTE observations of GRS 1915+105 in the chi-state. We interpret the behavior of the hard power law tail spectrum as coming from inverse Compton scattering of soft disk photons on a thermally dominated hybrid corona above the accretion disk. GRS 1915+105 shows a strong, variable reflection ampli

  11. Eric G. Blackman, George B. Field

    We develop a new nonlinear mean field dynamo theory that couples field growth to the time evolution of the magnetic helicity and the turbulent electromotive force, $\emfb$. We show that the difference between kinetic and current helicities emerges naturally as the growth driver when the time derivative of $\emfb$ is coupled into the theory. The solutions pre

  12. Gabor Etesi

    In this letter we provide a reformulation of the strong cosmic censor conjecture taking into account recent results on Malament--Hogarth space-times. We claim that the strong version of the cosmic censor conjecture can be formulated by postulating that a physically relevant space-time is either globally hyperbolic or possesses the Malament--Hogarth property.

  13. Matthias Fuchs, Michael E. Cates

    The nonlinear rheological properties of dense suspensions are discussed within simplified models, suggested by a recent first principles approach to the model of Brownian particles in a constant-velocity-gradient solvent flow. Shear thinning of colloidal fluids and dynamical yielding of colloidal glasses arise from a competition between a slowing down of str

  14. Bert Janssen, Yolanda Lozano

    We construct a non-Abelian world volume effective action for a system of multiple M-theory gravitons. This action contains multipole moment couplings to the eleven-dimensional background potentials. We use these couplings to study, from the microscopical point of view, giant graviton configurations where the gravitons expand into an M2-brane, with the topolo

  15. E. H. Lieb, F. Y. Wu

    In 1968 we published the solution of the ground state energy and wave function of the one-dimensional Hubbard model, and we also showed that there is no Mott transition in this model. Details of the analysis have never been published, however. As the Hubbard model has become increasingly important in condensed matter physics, relating to topics such as the t

  16. A. S. Kapoyannis

    The evolution of a hadronic system after its chemical decomposition is described through a model that conserves the hadronic multiplicities to their values at chemical freeze-out. In the partition function describing the model all known hadronic resonances with masses up to 2400 MeV have been included. The state of the system is found as function of temperat

  17. Mateusz Ruszkowski, Mitchell C. Begelman

    There is mounting observational evidence from Chandra for strong interaction between keV gas and AGN in cooling flows. It is now widely accepted that the temperatures of cluster cores are maintained at a level of 1 keV and that the mass deposition rates are lower than earlier ROSAT/Einstein values. Recent theoretical results suggest that thermal conduction c

  18. M. Jöstingmeier, A. Dorneich, E. Arrigoni, W. Hanke

    We study the scaling properties of the quantum ``projected'' SO(5) model in three dimensions by means of a highly accurate Quantum-Monte-Carlo analysis. Within the parameter regime studied (temperature and system size), we show that the scaling behavior is consistent with a SO(5)-symmetric critical behavior in a relative extendent transient regime. T

  19. Mark Hindmarsh

    A theory for studying the dynamic scaling properties of branes and relativistic topological defect networks is presented. The theory, based on a relativistic version of the level set method, well-known in other contexts, possesses self-similar ``scaling'' solutions, for which one can calculate many quantities of interest. Here, the length and area de

  20. J. W. Moffat

    A nonlocal quantum gravity theory is presented which is finite and unitary to all orders of perturbation theory. Vertex form factors in Feynman diagrams involving gravitons suppress graviton and matter vacuum fluctuation loops by introducing a low-energy gravitational scale, Lambda_{Gvac} < 2.4 X 10^{-3} eV. Gravitons coupled to non-vacuum matter loops and m

  21. C. J. Walcher, J. W. Fried, A. Burkert, R. S. Klessen

    The morphological properties of the Carina, Sculptor and Fornax dwarfs are investigated using new wide field data with a total area of 29 square degrees. The stellar density maps are derived, hinting that Sculptor possesses tidal tails indicating interaction with the Milky Way. Contrary to previous studies we cannot find any sign of breaks in the density pro

  22. Enrique Ruiz Arriola, Wojciech Broniowski

    We compute the pion light-cone wave function and the pion quark distribution amplitude in the Nambu-Jona-Lasinio model. We use the Pauli-Villars regularization method and as a result the distribution amplitude satisfies proper normalization and crossing properties. In the chiral limit we obtain the simple results, namely phi_pi(x)=1 for the pion distribution

  23. Sigbjorn Hervik

    In this paper we classify all 4+1 cosmological models where the spatial hypersurfaces are connected and simply connected homogeneous Riemannian manifolds. These models come in two categories, multiply transitive and simply transitive models. There are in all five different multiply transitive models which cannot be considered as a special case of a simply tr

  24. Anton Matveentsev, Andrey Lyalin, Ilia A Solov&#39;yov, Andrey V Solov&#39;yov

    This work is devoted to the elucidation the applicability of jellium model to the description of alkali cluster properties on the basis of comparison the jellium model results with those derived from experiment and within ab initio theoretical framework. On the basis of the Hartree-Fock and local-density approximation deformed jellium model we have calculate

  25. H. Boutaleb-J, A. Chafik, A. L. Marrakchi

    We propose a new realisation of hybrid inflation in supergravity where the inflaton field does not appear in the superpotential but contributes only through the Kahler potential. The scalar potential derived from an R-invariant superpotential has the same form as that of the Linde&#39;s original version. The correct magnitude of the density perturbations amp

  26. Masako Asano, Yasuhiro Sekino

    We study one-loop effective action of Berkooz-Douglas Matrix theory and obtain non-abelian action of D0-branes in the longitudinal 5-brane background. In this paper, we extend the analysis of hep-th/0201248 and calculate the part of the effective action containing fermions. We show that the effective action is manifestly invariant under the loop-corrected SU

  27. G. Brodin, M. Marklund

    We present a proposal for a gravitational wave detector, based on the excitation of an electromagnetic mode in a resonance cavity. The mode is excited due to the interaction between a large amplitude electromagnetic mode and a quasi-monochromatic gravitational wave. The minimum metric perturbation needed for detection is estimated to the order 7.10^(-23) usi

  28. Gabor Etesi, Tamas Hausel

    In this paper we explicitly calculate the analogue of the &#39;t Hooft SU(2) Yang--Mills instantons on Gibbons--Hawking multi-centered gravitational instantons which come in two parallel families: the multi-Eguchi--Hanson, or A_k ALE gravitational instantons and the multi-Taub--NUT, or A_k ALF gravitational instantons. We calculate their action and find the

  29. Sandhya Choubey, S. F. King

    We calculate the time delays of neutrinos emitted in gamma ray bursts due to the effects of neutrino mass and quantum gravity using a time dependent Hubble constant which can significantly change the naive results presented hitherto in the literature for large redshifts, and gives some sensitivity to the details of dark energy. We show that the effects of ne

  30. Florian Deloup, Gwenael Massuyeau

    We show how the space of complex spin structures of a closed oriented three-manifold embeds naturally into a space of quadratic functions associated to its linking pairing. Besides, we extend the Goussarov-Habiro theory of finite type invariants to the realm of compact oriented three-manifolds equipped with a complex spin structure. Our main result states th

  31. Peter Schneider, Marco Lombardi

    Previous work on three-point statistics of cosmic shear has mainly concentrated on the convergence, or on aperture measures of the shear. However, as has become clear recently for the two-point statistics of cosmic shear, the basic quantity that should be used is the correlation function: first, it is much easier to measure from observational data, since it

  32. K. A. Kirkpatrick

    A simple classical probabilistic system (a simple card game) classically exemplifies Aharonov and Vaidman&#39;s &#34;Three-Box &#39;paradox&#39;&#34; [J. Phys. A 24, 2315 (1991)], implying that the Three-Box example is neither quantal nor a paradox and leaving one less difficulty to busy the interpreters of quantum mechanics. An ambiguity in the usual expres

  33. Toru Aonishi, Masato Okada

    We propose a theoretical framework to study the cooperative behavior of dynamically coupled oscillators (DCOs) that possess dynamical interactions. Then, to understand synchronization phenomena in networks of interneurons which possess inhibitory interactions, we propose a DCO model with dynamics of interactions that tend to cause 180-degree phase lags. Empl

  34. Anil K. Patnaik, J. Q. Liang, K. Hakuta

    We propose a novel configuration that utilizes electromagnetically induced transparency (EIT) to tailor a fiber mode propagating inside a thin optical fiber and coherently control its dispersion properties to drastically reduce the group velocity of the fiber mode. The key to this proposal is: the evanescent-like field of the thin fiber strongly couples with

  35. M. Kitazawa, T. Koide, T. Kunihiro, Y. Nemoto

    We investigate effects of the vector interaction on chiral and color superconducting (CSC) phase transitions at finite density and temperature in a simple Nambu-Jona-Lasinio model. It is shown that the repulsive density-density interaction coming from the vector term, which is present in the effective chiral models but has been omitted, enhances the competit

  36. Hao Chen

    We first propose a new separability criterion based on algebraic-geometric invariants of bipartite mixed states introduced in [1], then prove that for all low ranks r <m+n-2, generic rank r mixed states in mxn systems have relatively high Schmidt numbers (thus entangled) by this separability criterion. This also means that the algebraic-geometric separabilit

  37. J. Batle, A. R. Plastino, M. Casas, A. Plastino

    We revisit the relationship between quantum separability and the sign of the relative q-entropies of composite quantum systems. The q-entropies depend on the density matrix eigenvalues p_i through the quantity omega_q = sum_i p_i^q. Renyi&#39;s and Tsallis&#39; measures constitute particular instances of these entropies. We perform a systematic numerical sur

  38. John Cortese

    The relative entropy description of Holevo-Schumacher-Westmoreland (HSW) classical channel capacity is applied to single qubit channels. A simple formula for the relative entropy of qubit density matrices in the Bloch sphere representation is derived. This formula is combined with the King-Ruskai-Szarek-Werner qubit channel ellipsoid picture to analyze sever

  39. L. Praxmeyer, K. Wodkiewicz

    We discuss the Kirkwood-Rihaczek phase space distribution and analyze a whole new class of quasi-distributions connected with this function. All these functions have the correct marginals. We construct a coherent state representation of such functions, discuss which operator ordering corresponds to the Kirkwood-Rihaczek distribution and their generalizations

  40. Laurent Chusseau, Jacques Arnaud, Fabrice Philippe

    The statistics of the light emitted by two-level lasers is evaluated on the basis of generalized rate equations. According to that approach, all fluctuations are interpreted as being caused by the jumps that occur in active and detecting atoms. The intra-cavity Fano factor and the photo-current spectral density are obtained analytically for Poissonian and qu

  41. Fam Le Kien, K. Hakuta, A. V. Sokolov

    We study beating of a probe field with a time-varying susceptibility in a coherently prepared Raman medium. We consider the general case of an arbitrary variation of susceptibility, which corresponds to a superposition of an arbitrary number of excited Raman transitions. We derive a general analytical solution and conservation relations for this process. We

  42. Benoit Depret, Philippe Verkerk, Daniel Hennequin

    The properties of the hollow beam produced by a conical lens are studied in detail. In particular, the impact of a rounded vertex is examined. It is shown that it could lead to drastic changes in the transverse distribution of the hollow beam, determined by the ratio between the transverse size of the incident beam and the size of the blunt area. An adequate

  43. S. V. Nedea, A. P. J. Jansen, J. J. Lukkien, P. A. J. Hilbers

    We have used Monte-Carlo methods and analytical techniques to investigate the influence of the characteristics, such as pipe length, diffusion, adsorption, desorption and reaction rates on the transient properties of Single-File Systems. The transient or the relaxation regime is the period in which the system is evolving to equilibrium. We have studied the s

  44. Rafał Podeszwa, Leszek Z. Stolarczyk, Karol Jankowski, Krzysztof Rubiniec

    To gain some insight into the structure and physical significance of the multiple solutions to the coupled-cluster doubles (CCD) equations corresponding to the Pariser-Parr-Pople (PPP) model of cyclic polyenes, complete solutions to the CCD equations for the A^{-}_{1g} states of benzene are obtained by means of the homotopy method. By varying the value of th

  45. A. Koshelev, A. Shutovich, Il. A. Solov&#39;yov, A. V. Solov&#39;yov

    We present a new theoretical framework for modelling the cluster growing process. Starting from the initial tetrahedral cluster configuration, adding new atoms to the system and absorbing its energy at each step, we find cluster growing paths up to the cluster sizes of more than 100 atoms. We demonstrate that in this way all known global minimum structures o

  46. D. Tonev, P. Petkov, A. Dewald, T. Klug

    Lifetime measurements in the mirror nuclei 47Cr and 47V were performed by means of the Doppler-shift attenuation method using the multidetector array EUROBALL, in conjunction with the ancillary detectors ISIS and the Neutron Wall. The determined transition strengths in the yrast cascades are well described by full pf shell model calculations.

  47. T. J. Schuck, H. Timmers, M. Dasgupta

    Excitation functions for quasi-elastic scattering have been measured at backward angles for the systems 32,34S+197Au and 32,34S+208Pb for energies spanning the Coulomb barrier. Representative distributions, sensitive to the low energy part of the fusion barrier distribution, have been extracted from the data. For the fusion reactions of 32,34S with 197Au cou

  48. L. Benet, J. Flores, H. Hernandez-Saldaña, F. M. Izrailev

    Quantum-classical correspondence for the average shape of eigenfunctions and the local spectral density of states are well-known facts. In this paper, the fluctuations that quantum mechanical wave functions present around the classical value are discussed. A simple random matrix model leads to a Gaussian distribution of the amplitudes. We compare this predic

  49. Manabu Machida, Keiji Saito, Seiji Miyashita

    We study the quantum localization phenomena for a random matrix model belonging to the Gaussian orthogonal ensemble (GOE). An oscillating external field is applied on the system. After the transient time evolution, energy is saturated to various values depending on the frequencies. We investigate the frequency dependence of the saturated energy. This depende

  50. Luca Salasnich

    We study the Bose-Einstein condensation (BEC) for a relativistic ideal gas of bosons. In the framework of canonical thermal field theory, we analyze the role of particles and anti-particles in the determination of BEC transition temperature. At the BEC transition point we obtain two universal curves, i.e. valid for any mass value: the scaled critical tempera

  51. Alexander Cardona, Catherine Ducourtioux, Sylvie Paycha

    zeta-regularized traces, resp. super-traces, are defined on a classical pseudo-differential operator A by: tr^Q(A):= f.p.tr(A Q^{-z})_{|_{z=0}}, resp. str^Q(A):= f.p.str(A Q^{-z})_{|_{z=0}}, where f.p. refers to the finite part and Q is an (invertible and admissible) elliptic reference operator with positive order. They are widly used in quantum field theory

  52. Armand Brumer, Kenneth Kramer

    Let $A$ be a semistable abelian variety defined over ${\bf Q}$ with bad reduction only at one prime $p$. Let $L= {\bf Q}(A[\ell])$ be the $\ell$-division field of $A$ for a prime $\ell$ not equal to $p$ and let $F={\bf Q}(μ_\ell)$ be the cyclotomic field generated by the group of $\ell^{th}$-roots of unity. We study the varieties $A$ for which $H={\rm Gal(L/

  53. Jesus De Loera, Shmuel Onn

    Multi-way tables with specified marginals arise in a variety of applications in statistics and operations research. We provide a comprehensive complexity classification of three fundamental computational problems on tables: existence, counting and entry-security. One major outcome of our work is that each of the following problems is intractable already for

  54. Dirk Mittenhuber

    We solve a model problem from single crystal plasticity.We consider 4 slip systems in the plane with orthogonal slip-directions and equal slip rates, forward as well as backwards. We compute the associated dissipation distance by solving an optimal control problem. It turns out that from a computational point of view computing the distance is inexpensive. We

  55. N. J. A. Sloane

    This paper gives a brief survey of binary single-deletion-correcting codes. The Varshamov-Tenengolts codes appear to be optimal, but many interesting unsolved problems remain. The connections with shift-register sequences also remain somewhat mysterious.

  56. J. E. Humphreys

    In this note we study simple modules for a reduced enveloping algebra U_chi(g) in the critical case when chi element of g^* is ``nilpotent&#39;&#39;. Some dimension formulas computed by Jantzen suggest modified versions of Weyl&#39;s dimension formula, based on certain reflecting hyperplanes for the affine Weyl group which might be associated to Kazhdan--Lus

  57. T. Mansour, Z. Stankova

    A 321-k-gon-avoiding permutation pi avoids 321 and the following four patterns: k(k+2)(k+3)...(2k-1)1(2k)23...(k+1), k(k+2)(k+3)...(2k-1)(2k)123...(k+1), (k+1)(k+2)(k+3)...(2k-1)1(2k)23...k, (k+1)(k+2)(k+3)...(2k-1)(2k)123...k. The 321-4-gon-avoiding permutations were introduced and studied by Billey and Warrington [BW] as a class of elements of the symmetri

  58. Rasul Shafikov, Christian Wolf

    In this paper we study the dynamics of regular polynomial automorphisms of C^n. These maps provide a natural generalization of complex Henon maps in C^2 to higher dimensions. For a given regular polynomial automorphism f we construct a filtration in C^n which has particular escape properties for the orbits of f. In the case when f is hyperbolic we obtain a c

  59. T. Mestdag, W. Sarlet, E. Martinez

    We develop an alternative view on the concept of connections over a vector bundle map, which consists of a horizontal lift procedure to a prolonged bundle. We further focus on prolongations to an affine bundle and introduce the concept of affineness of a generalised connection.

  60. S. Skryabin

    We investigate the transformed Hopf algebras in Hopf Galois extensions. The final goal of this paper is to introduce certain triangular Hopf algebras associated with restricted Frobenius Lie algebras over a field of characteristic $p>0$.

  61. G. Nebe, E. M. Rains, N. J. A. Sloane

    A certain family of orthogonal groups (called &#34;Clifford groups&#34; by G. E. Wall) has arisen in a variety of different contexts in recent years. These groups have a simple definition as the automorphism groups of certain generalized Barnes-Wall lattices. This leads to an especially simple construction for the usual Barnes-Wall lattices. This is based on

  62. Qin Lu

    In this paper, we calculate the p-torsion of the Farrell cohomology for low genus pure mapping class groups with punctures, where p is an odd prime. Here, `low genus&#39; means g=1,2,3; and `pure mapping class groups with punctures&#39; means the mapping class groups with any number of punctures, where the punctures are not allowed to be permuted. These calc

  63. Kiyokazu Nagatomo, Akihiro Tsuchiya

    Based on any chiral vertex operator algebra satisfying a suitable finiteness condition, the semisimplicity of the zero-mode algebra as well as a regularity for induced modules, we construct conformal field theory over the projective line with the chiral vertex operator algebra as symmetries of the theory. We appropriately generalize the argument in [TUY] so

  64. Ofer Gabber, Lorenzo Ramero

    We develop almost ring theory, which is a domain of mathematics somewhere halfway between ring theory and category theory (whence the difficulty of finding appropriate MSC-class numbers). We apply this theory to valuation theory and to p-adic analytic geometry. You should really have a look at the introductions (each chapter has one).

  65. Edward S. Letzter

    Let R be an associative ring with identity. We study an elementary generalization of the classical Zariski topology, applied to the set of isomorphism classes of simple left R-modules (or, more generally, simple objects in a complete abelian category). Under this topology the points are closed, and when R is left noetherian the corresponding topological spac

  66. Christof Schmidhuber

    In this talk I first briefly review how far we have come in answering old questions about the most fundamental building blocks of matter. I begin with things we know, which is the Standard Model, and then talk about things we can guess, which is superstring theory. After this review I discuss a key point at which our understanding of superstring theory prese

  67. M. I. Caicedo, N. F. Svaiter

    We discuss the approach of effective field theory on a d-dimensional Euclidean space in a scalar theory with two different mass scales in the presence of flat surfaces. Then considering Dirichlet and Neumann boundary conditions, we implement the renormalization program in the lambda phi^{4} theory in a region bounded by two parallel hyperplanes in the one-lo

  68. A. Agarwal, L. Akant, G. S. Krishnaswami, S. G. Rajeev

    We formulate the planar `large N limit&#39; of matrix models with a continuously infinite number of matrices directly in terms of U(N) invariant variables. Non-commutative probability theory, is found to be a good language to describe this formulation. The change of variables from matrix elements to invariants induces an extra term in the hamiltonian,which i

  69. Katsuyuki Sugiyama, Kentaroh Yoshida

    We study classical solutions in Berenstein-Maldacena-Nastase (BMN) matrix model. A supersymmetric (1/2 BPS) fuzzy sphere is one of the classical solutions and corresponds to a giant graviton. We also consider other classical solutions, such as non-supersymmetric fuzzy sphere and harmonic oscillating gravitons. Some properties of oscillating gravitons are dis

  70. F. R. Klinkhamer

    A new mechanism for T and CPT violation is reviewed, which relies on chiral fermions, gauge interactions and nontrivial spacetime topology. Also discussed are the possible effects on the propagation of electromagnetic waves in vacuo, in particular for the cosmic microwave background radiation.

  71. A. Zerwekh, C. Dib, R. Rosenfeld

    We study the process p bar{p} --> gamma gamma gamma as a signal for associated photon-technipion production at the Tevatron. This is a clean signature with relatively low background. Resonant and non-resonant contributions are included and we show that technicolor models can be effectively probed in this mode.

  72. A. Szczurek, J. Speth

    The interplay of pQCD, pion exchange and FSI effects is studied for the gamma gamma --> pi^+ pi^- reaction in the region of 2 GeV < W_{gamma gamma} < 6 GeV. We find strong interference effects between pQCD and soft pion-exchange amplitudes up to W_{gamma gamma} ~ 4 GeV. We discuss to which extend the conventional hadronic FSI effects could cloud the pQCD eff

  73. S. Digal, S. Fortunato, P. Petreczky, H. Satz

    The geometric clustering of partons in the transverse plane of nuclear collisions leads for increasing A or sqrt(s) to percolation. In the resulting condensate, the partons are deconfined but not yet in thermal equilibrium. We discuss quarkonium dissociation in this precursor of the quark-gluon plasma, with an onset of dissociation when the saturation scale

  74. A. V. Strelchenko

    By the Schwinger proper-time method, the one-loop contribution to the anomalous magnetic moment of the W-boson is calculated at high temperature. It is shown that the value of AMM is positive and depends linearly upon temperature.

  75. D. J. Broadhurst, A. L. Kataev

    Analytical all-orders results are presented for the one-renormalon-chain contributions to the Bjorken unpolarized sum rule for the F_1 structure function of nu N deep-inelastic scattering in the large-N_F limit. The feasibility of estimating higher order perturbative QCD corrections, by the process of naive nonabelianization (NNA), is studied, in anticipatio

  76. J. Blümlein, H. Kawamura

    We derive QED radiators for the universal corrections to polarized electron scattering. To 5th order in the coupling constant the flavor non-singlet and singlet contributions are calculated. We derive the non-singlet and singlet exponentiation of the leading terms propertional to (alpha ln^2(x))^k to all orders.

  77. N. G. Deshpande, Nita Sinha, Rahul Sinha

    We present a method for measuring the weak phase gamma using isospin analysis of three body B decays into K pi pi channels. Differential decay widths and time dependent asymmetry in B_d -> K_s pi^+pi^- mode needs to be measured into even isospin pi pi states. The method can be used to extract gamma, as well as, the size of the electroweak penguin contributio

  78. Hyun Kyu Lee

    It has been suggested that the overdense region as a result of inhomogeneities in the early Universe would have undergone a collapse into the primordial black holes(PBH). In this work, we discuss a possible constraint on the PBH formation in the radiation dominated epoch by imposing the generalized second law of thermodynamics in the context of spherically c

  79. Volker D. Burkert

    I discuss recent results on the electroproduction and photoproduction of mesons in the region of non-strange baryon resonances. Results on the quadrupole transition from the ground state nucleon to the Delta(1232) show the importance of pion cloud contributions to explain the observed quadrupole transition multipoles. The excitation of the &#34;Roper&#34; re

  80. Frank Brechtefeld

    The two-dimensional O(3) model at a vacuum angle theta=pi is investigated. This model has a severe sign problem. By a Wolff cluster algorithm an integer or half-integer topological charge is assigned to each cluster. The meron clusters (clusters with half-integer topological charge) are used to construct an improved estimator for the correlation function of

  81. Ivan De Mitri

    There has been a big effort in the past twenty years with at least a couple of generations of experiments which searched for supermassive GUT magnetic monopoles in the cosmic radiation. Here a short review of these searches is given, together with a brief description of the theoretical framework and of the detection techniques.

  82. Joao Magueijo, Lee Smolin

    The hypothesis that the Lorentz transformations may be modified at Planck scale energies is further explored. We present a general formalism for theories which preserve the relativity of inertial frames with a non-linear action of the Lorentz transformations on momentum space. Several examples are discussed in which the speed of light varies with energy and

  83. Etera R Livine

    In the search for a covariant formulation for Loop Quantum Gravity, spin foams have arised as the corresponding discrete space-time structure and, among the different models, the Barrett-Crane model seems the most promising. Here, we study its boundary states and introduce cylindrical functions on both the Lorentz connection and the time normal to the studie

  84. Metin Gurses, Ozgur Sarioglu

    We consider Einstein Born-Infeld theory with a null fluid in Kerr-Schild Geometry. We find accelerated charge solutions of this theory. Our solutions reduce to the Plebanski solution when the acceleration vanishes and to the Bonnor-Vaidya solution as the Born-Infeld parameter b goes to infinity. We also give the explicit form of the energy flux formula due t

  85. Jahanzeb Sherwani, Nosheen Ali, Nausheen Lotia, Zahra Hayat

    Clusters of computers have emerged as mainstream parallel and distributed platforms for high-performance, high-throughput and high-availability computing. To enable effective resource management on clusters, numerous cluster managements systems and schedulers have been designed. However, their focus has essentially been on maximizing CPU performance, but not

  86. Elisa Bertino, Barbara Catania, Paolo Perlasca

    The problem of integrating knowledge from multiple and heterogeneous sources is a fundamental issue in current information systems. In order to cope with this problem, the concept of mediator has been introduced as a software component providing intermediate services, linking data resources and application programs, and making transparent the heterogeneity o

  87. Thomas Lukasiewicz

    Recently, it has been shown that probabilistic entailment under coherence is weaker than model-theoretic probabilistic entailment. Moreover, probabilistic entailment under coherence is a generalization of default entailment in System P. In this paper, we continue this line of research by presenting probabilistic generalizations of more sophisticated notions

  88. Dino Pedreschi, Salvatore Ruggieri, Jan-Georg Smaus

    Termination of logic programs depends critically on the selection rule, i.e. the rule that determines which atom is selected in each resolution step. In this article, we classify programs (and queries) according to the selection rules for which they terminate. This is a survey and unified view on different approaches in the literature. For each class, we pre

  89. Burkhard Militzer, E. L. Pollock

    Interactions never lower the ground state kinetic energy of a quantum system. However, at nonzero temperature, where the system occupies a thermal distribution of states, interactions can reduce the kinetic energy below the noninteracting value. This can be demonstrated from a first order weak coupling expansion. Simulations (both variational and restricted

  90. Augusto Gonzalez, Roberto Capote

    Exact diagonalization studies of the level density in a six-electron quantum dot under magnetic fields around 7 T (``filling factor&#39;&#39; around 1/2) are reported. In any spin-polarization channel, two regimes are visible in the dot excitation spectrum: one corresponding to interacting quasiparticles (i.e. composite fermions) for excitation energies belo

  91. A. L. Pokrovsky, A. L. Efros

    An analytical theory of low frequency electromagnetic waves in metallic photonic crystals with a small volume fraction of a metal is presented. The evidence of the existence of such waves has been found recently via experiments and computations. We have obtained an exact dispersion equation for omega (k) and studied the cutoff frequency omega_0 = omega(0) as

  92. A. L. Pokrovsky, A. L. Efros

    A diffraction theory in a system consisting of left-handed and right-handed materials is proposed. The theory is based upon the Huygens&#39;s principle and the Kirchhoff&#39;s integral and it is valid if the wavelength is smaller than any relevant length of the system. The theory is applied to the calculation of the smearing of the foci of the Veselago lens

  93. Debashish Chowdhury, Dietrich Stauffer

    The Sole-Manrubia model of ``macro&#39;&#39;-evolution describes the origination, evolution and extinction of species on geological time scales. We report some properties of this model which provide deep insight into this simple model which captures several realistic features.

  94. D. Alfè, M. J. Gillan

    Previous first-principles calculations of the melting properties of Si, based on the local-density approximation (LDA) for electronic exchange-correlation energy, under-predict the melting temperature by ~ 20%. We present new first-principles results demonstrating that this problem is due to non-cancellation of exchange-correlation errors between the semicon

  95. A. Gurevich

    Mechanisms of vortex dynamics and pinning and self-field effects which could account for the thickness dependence of the critical current density J_c of superconducting films are addressed. It is shown that at low magnetic fields B, the 2D single-vortex pinning and thermal fluctuations yield J_c proportional to (1/sqrt{d})exp[-(d_m/d)^{1/2}], if the film thi

  96. F. Gobet, S. Ciliberto, T. Dauxois

    We study energy relaxation in a phenomenological model for polymer built from rheological considerations: a one dimensional nonlinear lattice with dissipative couplings. These couplings are well known in polymer&#39;s community to be possibly responsible of beta-relaxation (as in Burger&#39;s model). After thermalisation of this system, the extremities of th

  97. Paul Jefferies, Neil F. Johnson

    In light of the growing interest in agent-based market models, we bring together several earlier works in which we considered the topic of self-consistent market modelling. Building upon the binary game structure of Challet and Zhang, we discuss generalizations of the strategy reward scheme such that the agents seek to maximize their wealth in a more direct

  98. Jozef Strecka, Michal Jascur

    The generalized mapping transformation technique is used to obtain the exact solution for the transverse Ising model on decorated planar lattices. Within this scheme, the basic thermodynamic quantities are calculated for different planar lattices with arbitrary spins of decorating atoms. The particular attention has been paid to the investigation of the tran

  99. T. Dahm, A. I. Posazhennikova, K. Maki

    The recently discovered superconductivity in MgB2 has created the world sensation. In spite of the relatively high superconducting transition temperature Tc=39K, the superconductivity is understood in terms of rare two gap superconductor with energy gaps attached to the sigma- and pi-band. However, this simple model cannot describe the temperature dependent

  100. Michai Jascur, Jozef Strecka

    In this work we deal with doubly decorated Ising-Heisenberg models on planar lattices. Applying the generalized decoration-iteration transformation we obtain exact results for the antiferromagnetic version of the model. The existence of a new quantum dimerized phase is predicted and its physical properties are studied and analyzed. Particular attention has b