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February 2003 arXiv papers

Showing 1–100 of 2,840 papers

  1. Frederick W. Strauch, Philip R. Johnson, Alex J. Dragt, C. J. Lobb

    Based on a quantum analysis of two capacitively coupled current-biased Josephson junctions, we propose two fundamental two-qubit quantum logic gates. Each of these gates, when supplemented by single-qubit operations, is sufficient for universal quantum computation. Numerical solutions of the time-dependent Schroedinger equation demonstrate that these operati

  2. Fabrizio Anfuso, Sebastian Eggert

    We study a Luttinger Liquid in a finite one-dimensional wire with box-like boundary conditions by considering the local distribution of the single particle spectral weight. This corresponds to the experimental probability of extracting a single electron at a given place and energy, which can be interpreted as the square of an electron wave-function. For the

  3. Yuexing Li, Ralf S. Klessen, Mordecai-Mark Mac Low

    We study the effect of varying the equation of state on the formation of stellar clusters in turbulent molecular clouds, using three-dimensional, smoothed particle hydrodynamics simulations. Our results show that the equation of state helps determine how strongly self-gravitating gas fragments. The degree of fragmentation decreases with increasing \new{polyt

  4. Paul Federbush

    A polymer expansion is given for the Quantum Heisenberg Ferromagnet wave function. Working on a finite lattice, one is dealing entirely with algebraic identities; there is no question of convergence. The conjecture to be pursued in further work is that effects of large polymers are small. This is relevant to the question of the utility of the expansion and i

  5. Rene A. Ong

    VERITAS is a new, major ground-based gamma-ray observatory designed to significantly advance our understanding of extreme astrophysical processes in the universe. The observatory comprises seven large-aperture (12m diameter) Cherenkov telescopes, each equipped with an imaging camera. The first phase of VERITAS (consisting of four telescopes) is currently und

  6. Nao Suzuki, David Tytler, David Kirkman, John M. O'Meara

    We describe a new method to calibrate the relative flux levels in spectra from the HIRES echelle spectrograph on the Keck-I telescope. Standard data reduction techniques that transfer the instrument response between HIRES integrations leave errors in the flux of 5 - 10%, because the effective response varies. The flux errors are most severe near the ends of

  7. Marco Fatuzzo, Fulvio Melia

    Sgr A East appears to be a single, mixed morphology 10,000 year-old supernova remnant (SNR) at the Galactic Center. It also appears to belong to a class of remnants that have been observed and detected at 1720 MHz, the transition frequency of OH maser emission. However, if the EGRET source 3EG J1746-2852 conincident with the Galactic center is itself associa

  8. G. Zheng, C. H. Patterson

    Unrestricted Hartree-Fock calculations on La0.5Ca0.5MnO3 and La0.33Ca0.67MnO3 in the full magnetic unit cell show that the magnetic ground states of these compounds consist of 'ferromagnetic molecules' or polarons ordered in herring-bone patterns. Each polaron consists of either three or five Mn ions separated by O- ions with a magnetic moment oppose

  9. L. Pozzetti, A. Cimatti, G. Zamorani, E. Daddi

    We present the galaxy rest-frame near-IR Luminosity Function (LF) and its cosmic evolution to z=1.5 based on a spectroscopic survey of a magnitude limited sample of galaxies with Ks<20 (the K20 survey, Cimatti et al. 2002b). The LFs have been derived in the rest-frame J and Ks bands using 3 z bins (z_mean= 0.5, 1, 1.5) and compared to the local near-IR LF. T

  10. J. N. Das, K. Chakrabarti, S. Paul

    Hyperspherical partial wave approach has been applied here in the study of double photoionization of the helium atom for equal energy sharing geometry at 20 eV excess energy. Calculations have been done both in length and velocity gauges and are found to agree with each other, with the CCC results and with experiments and exhibit some advantages of the corre

  11. Thomas Bickel

    We investigate excluded-volume effects in a bidisperse colloidal suspension near a flexible interface. Inspired by a recent experiment by Dinsmore et al. (Phys. Rev, Lett. 80, 409 (1998)), we study the adsorption of a mesoscopic bead on the surface and show that depletion forces could in principle lead to particle encapsulation. We then consider the effect o

  12. Dennis D. Dietrich

    The exact fermion propagator in a classical time-dependent gauge field is derived by solving the equation of motion for the Dirac Green&#39;s functions. From the retarded propagator obtained in this way the momentum spectrum for the produced fermion pairs is calculated. Different approximations and the exact solution for the propagator and the momentum spect

  13. Massimo Meneghetti, Matthias Bartelmann, Lauro Moscardini

    We perform ray-tracing simulations evaluating the effect of a cD galaxy on the strong lensing properties of five galaxy cluster halos obtained from N-body simulations. The cD galaxy is modelled using both axially symmetric and elliptical models and assuming several masses for its dark matter halo. The effect of the cD orientation with respect to the mass dis

  14. Kingman Cheung

    Based on the observed neutrino mass-square differences and mixings, we derive a few general patterns for the neutrino mass matrix in the flavor basis, which can correctly describe the atmospheric and solar neutrino data. Upon the most recent result on the absolute neutrino mass bound from WMAP, we can rule out a large portion of the parameter space that clai

  15. Hao Jin, Hai-Hu Wen

    Current-voltage ($I$-$V$) characteristics of Tl$_2$Ba$_2$CaCu$_2$O$_8$ thin films in zero magnetic field are measured and analyzed with the conventional Kosterlitz-Thouless-Berezinskii (KTB) approach, dynamic scaling approach and finite-size scaling approach, respectively. It is found from these results that the $I$-$V$ relation is determined by the vortex-u

  16. V. B. Braginsky, S. P. Vyatchanin

    Thermodynamical fluctuations of temperature in mirrors may produce surface fluctuations not only through thermal expansion in mirror body but also through thermal expansion in mirror coating. We analyze the last &#34;surface&#34; effect which can be larger than the first &#34;volume&#34; one due to larger thermal expansion coefficient of coating material and

  17. R. P. Malik

    We discuss the dynamics of a particular two-dimensional (2D) physical system in the four dimensional (4D) (non-)commutative phase space by exploiting the consistent Hamiltonian and Lagrangian formalisms based on the symplectic structures defined on the 4D (non-)commutative cotangent manifolds. The noncommutativity exists {\it equivalently} in the coordinate

  18. L. Canet, B. Delamotte, D. Mouhanna, J. Vidal

    On the example of the three-dimensional Ising model, we show that nonperturbative renormalization group equations allow one to obtain very accurate critical exponents. Implementing the order $\partial^4$ of the derivative expansion leads to $ν=0.632$ and to an anomalous dimension $η=0.033$ which is significantly improved compared with lower orders calculatio

  19. M. Faisst, J. Kuhn, T. Seidensticker, O. Veretin

    We present results for the three-loop top quark contributions to the rho parameter in the limit of large top quark mass. The simultaneous dependence on the mass of the Higgs boson M_H and the mass of the top quark m_t is obtained from expansions in the range of M_H around m_t and in the limit M_H >> m_t. In combination with the previous result for M_H = 0 th

  20. A. Costa, G. Macedonio

    Viscous heating plays an important role in the dynamics of fluids with strongly temperature-dependent viscosity because of the coupling between the energy and momentum equations. The heat generated by viscous friction produces a local temperature increase near the tube walls with a consequent decrease of the viscosity which may dramatically change the temper

  21. Jean-Philippe Uzan, Ulrich Kirchner, George F. R. Ellis

    Inter alia, the high precision WMAP data on Cosmic Microwave Background Radiation marginally indicate that the universe has positively curved (and hence spherical) spatial sections. In this paper, we take this data seriously and consider some of the consequences for the background dynamics. In particular, we show that this implies a limit to the number of e-

  22. V. I. Yukalov, S. Gluzman, D. Sornette

    A novel method of summation for power series is developed. The method is based on the self-similar approximation theory. The trick employed is in transforming, first, a series expansion into a product expansion and in applying the self-similar renormalization to the latter rather to the former. This results in self-similar factor approximants extrapolating t

  23. Ph. Blanchard, T. Krueger

    We formulate a simple edge generation rule based on an inverse like mass action principle for random graphs over a structured vertex set. We show that under very weak assumptions on the structure generating distribution we obtain a scale free distribution for the degree. We furthermore introduce and study a &#34;my friends are your friends&#34; local search

  24. A. E. Shalyt-Margolin, J. G. Suarez

    In this paper Quantum Mechanics with Fundamental Length is chosen as the theory for describing the early Universe. This is possible due to the presence in the theory of General Uncertainty Relations from which unavoidable it follows that in nature a fundamental length exits. Here Quantum Mechanics with Fundamental Length is obtained as a deformation of Quant

  25. Spyros Basilakos

    We study the supercluster shape properties of the recently compiled SDSS cluster catalog using an approach based on differential geometry. We detect superclusters by applying the percolation algorithm to observed cluster populations, extended out to $z_{\rm max}\leq 0.23$ in order to avoid selection biases. We utilize a set of shapefinders in order to study

  26. P. H. Chavanis, M. Rieutord

    We compute statistical equilibrium states of rotating self-gravitating systems enclosed within a box by maximizing the Fermi-Dirac entropy at fixed mass, energy and angular momentum. We increase the rotation up to the Keplerian limit and describe the flattening of the configuration until mass shedding occurs. At the maximum rotation, the system develops a cu

  27. P. Migliozzi, F. Terranova

    In this paper we quantify the trade-off between setups optimized to be ancillary to Phase II Superbeams or Neutrino Factories and experiments tuned for maximal sensitivity to the subdominant terms of the neutrino transition probability at the atmospheric scale (``maximum discovery potential&#39;&#39;). In particular, the theta(13) sensitivity is computed for

  28. A. Deandrea, G. Nardulli, A. D. Polosa

    We present an evaluation of the strong couplings JD^(*)D^(*) and JD^(*)D^(*)pi by an effective field theory of quarks and mesons. These couplings are necessary to calculate pi+J/psi --> D^(*)+barD^(*) cross sections, an important background to the J/psi suppression signal in the quark-gluon plasma. We write down the general effective lagrangian and compute t

  29. C. Marliere, S. Prades, F. Celarie, D. Dalmas

    We have studied the low speed fracture regime for different glassy materials with variable but controlled length scales of heterogeneity in a carefully mastered surrounding atmosphere. By using optical and atomic force microscopy (AFM) techniques we tracked in real-time the crack tip propagation at the nanometer scale on a wide velocity range (mm/s - pm/s an

  30. D. Emmanuel-Costa, S. Wiesenfeldt

    It is widely believed that minimal supersymmetric SU(5) GUTs have been excluded by the SuperKamiokande bound for the proton decay rate. In the minimal model, however, the theoretical prediction assumes unification of Yukawa couplings, Y_d=Y_e, which is known to be badly violated. We analyze the implications of this fact for the proton decay rate. In a consis

  31. Bérengère Abou, Daniel Bonn, Jacques Meunier

    We investigate the nonlinear rheological behavior of colloidal suspensions of Laponite, a synthetic clay, driven by a steady and homogeneous shear strain. We show that the external drive leads to a drastic slowing down of the aging dynamics or even, in some cases, in the rejuvenation of the system. Under shear, after a surprisingly long time, the spontaneous

  32. M. Bawin, S. A. Coon

    We study the radial Schroedinger equation for a particle in the field of a singular inverse square attractive potential. This potential is relevant to the fabrication of nanoscale atom optical devices, is said to be the potential describing the dipole-bound anions of polar molecules, and is the effective potential underlying the universal behavior of three-b

  33. H. Castillo, C. A. Dominguez, M. Loewe

    The electromagnetic form factors of the nucleon, in the space-like region, are determined from three-point function Finite Energy QCD Sum Rules. The QCD calculation is performed to leading order in perturbation theory in the chiral limit, and to leading order in the non-perturbative power corrections. The results for the Dirac form factor, $F_1(q^2)$, are in

  34. G. G. Raffelt

    The observed flavor oscillations of solar and atmospheric neutrinos determine several elements of the leptonic mixing matrix, but leave open the small mixing angle Theta_13, a possible CP-violating phase, the mass ordering, the absolute mass scale m_nu, and the Dirac vs. Majorana property. Progress will be made by long-baseline, tritium endpoint, and 2-beta

  35. Pierre Kestener, Alain Arneodo

    We generalize the wavelet transform modulus maxima (WTMM) method to multifractal analysis of 3D random fields. This method is calibrated on synthetic 3D monofractal fractional Brownian fields and on 3D multifractal singular cascade measures as well as their random function counterpart obtained by fractional integration. Then we apply the 3D WTMM method to th

  36. Xin Wu, Tian-yi Huang

    Lyapunov exponents (LEs) are key indicators of chaos in dynamical systems. In general relativity the classical definition of LE meets difficulty because it is not coordinate invariant and spacetime coordinates lose their physical meaning as in Newtonian dynamics. We propose a new definition of relativistic LE and give its algorithm in any coordinate system,

  37. Lap-Ming Lin, Kwong-Sang Cheng, Wai-Mo Suen, Ming-Chung Chu

    We study the gravitational wave signals emitted from phase-transition induced collapses of rapidly rotating neutron stars to strange stars by performing 3D numerical simulations. Our preliminary results suggest that the complete conversion of neutron stars to strange stars would occur within a fraction of millisecond. We also find that the gravitational wave

  38. Tetsuya Shiromizu, Takashi Torii, Tomoko Uesugi

    We discuss D-braneworld cosmology, that is, the brane is described by the Born-Infeld action. Compared with the usual Randall-Sundrum braneworld cosmology where the brane action is the Nambu-Goto one, we can see some drastic changes at the very early universe: (i)universe may experience the rapid accelerating phase (ii)the closed universe may avoid the initi

  39. T. Farris, J. F. Gunion, H. E. Logan, S. Su

    We compute the cross section for e+e- --> nu nu-bar A, where A is the CP-odd scalar, in the general CP-conserving type-II two-Higgs-doublet model. We sum the contributions from the ``t-channel&#39;&#39; e+e- --> nu nu-bar W W --> nu nu-bar A graphs and ``s-channel&#39;&#39; e+e- --> Z A --> nu nu-bar A graphs, including their interference. Higgs-triangle gra

  40. C. Ledoux, P. Petitjean, R. Srianand

    We have searched for molecular hydrogen in damped Lyman-alpha (DLA) and sub-DLA systems at z>1.8 using UVES at the VLT. Out of the 33 systems in our sample, 8 have firm and 2 have tentative detections of associated H2 absorption lines. Considering that 3 detections were already known from past searches, H2 is detected in 13 to 20 percent of the newly-surveye

  41. V. K. Agrawal, P. Sreekumar

    We present the results of a systematic investigation of spectral evolution in the Z source GX 349+2, using data obtained during 1998 with Proportional-Counter-Array (PCA) on-board the RXTE satellite. The source traced a extended normal branch (NB) and flaring branch (FB) in the color-color diagram (CD) and hardness-intensity diagram (HID) during these observ

  42. PACS Collaboration, T. Umeda, S. Aoki, M. Fukugita

    We report on our study of two-flavor full QCD on anisotropic lattices using $O(a)$-improved Wilson quarks coupled with an RG-improved glue. The bare gauge and quark anisotropies corresponding to the renormalized anisotropy $ξ=a_s/a_t = 2$ are determined as functions of $β$ and $κ$, which covers the region of spatial lattice spacings $a_s\approx 0.28$--0.16 f

  43. Manuel Blickle, Robert Lazarsfeld

    Multiplier ideals, and the vanishing theorems they satisfy, have found many applications in recent years. In the global setting they have been used to study pluricanonical and other linear series on a projective variety. More recently, they have led to the discovery of some surprising uniform results in local algebra. The present notes aim to provide a gentl

  44. David J. Fernandez C., Bogdan Mielnik, Oscar Rosas-Ortiz, Boris F. Samsonov

    For a class of Schrodinger Hamiltonians the supersymmetry transformations can degenerate to simple coordinate displacements. We examine this phenomenon and show that it distinguishes the Weierstrass potentials including the one-soliton wells and periodic Lame functions. A supersymmetric sense of the addition formula for the Weierstrass functions is elucidate

  45. Ye Yeo

    We investigate the teleportation of an entangled two-qubit state using three-qubit GHZ and W channels. The effects of white noise on the average teleportation fidelity and amount of entanglement transmitted are also studied.

  46. P. Milman, R. Mosseri

    We present an unambiguous characterization of the rotation group SO(3) biconnectedness topology using two-qubit maximally entangled states. We show how to generate cyclic evolutions of these states, which are in one-to-one correspondence to closed paths in SO(3). The difference between the well known two classes of such paths translates into the gain of a gl

  47. J. A. Damborenea, I. L. Egusquiza, G. C. Hegerfeldt, J. G. Muga

    A natural approach to measure the time of arrival of an atom at a spatial region is to illuminate this region with a laser and detect the first fluorescence photons produced by the excitation of the atom and subsequent decay. We investigate the actual physical content of such a measurement in terms of atomic dynamical variables, taking into account the finit

  48. Walter Simmons, Sandip Pakvasa

    We examine a situation in which an information-carrying signal is sent from two sources to a common receiver. The radiation travels through free space in the presence of noise. The information resides in a relationship between the two beams. We inquire into whether itis possible, in principle, that the locations of the transmitters can be concealed from a pa

  49. G. W. Webb

    The standard zone plate assumes that the shortest ray connecting a radiation source and a detection point has a phase of 0 deg thereby defining a reference phase. Here we examine the experimental consequences of varying this reference phase from 0 deg to 360 deg. It is concluded that reference phase is an intrinsic and useful property of zone plates.

  50. Subhash Kak

    The early Greek and Indian cosmologies are summarized in this paper. The two traditions appear to have developed independently although after the time of Alexander they were consciously aware of each other. The focus and style of the two sciences was different owing to their different cosmologies. Perhaps the only science which worked more or less the same w

  51. Daniel M. Zuckerman

    We introduce an approach for performing &#34;very long&#34; computer simulations of the dynamics of simplified, folded proteins. Using an alpha-carbon protein model and a fine grid to mimic continuum computations at increased speed, we perform unbiased simulations which exhibit many large-scale conformational transitions at low cost. In the case of the 72-re

  52. Michal Demetrian

    It is shown in this paper that one does not need to use just exponential dumping factor when computing the Rutherford formula within Born approximation. Text, which is very simple, might be of interest for physics students as well as for physics teachers.

  53. Antonio Costa, Giovanni Macedonio

    Magma viscosity is strongly temperature-dependent. When hot magma flows in a conduit, heat is lost through the walls and the temperature decreases along the flow causing a viscosity increase. For particular values of the controlling parameters the steady-flow regime in a conduit shows two stable solutions belonging either to the slow or to the fast branch. A

  54. Christopher Haydock

    The relaxation effects in the perturbed angular correlation spectra of indium-111 human carbonic anhydrase I (HCA I) are the result of chemical transmutation and/or the complex Auger cascades that follow the electron capture decay of indium-111. Time differential K X ray coincidence perturbed angular correlation (PAC) spectroscopy shows that these relaxation

  55. P. Leboeuf, A. G. Monastra

    We investigate the thermodynamics of a Fermi gas whose single-particle energy levels are given by the complex zeros of the Riemann zeta function. This is a model for a gas, and in particular for an atomic nucleus, with an underlying fully chaotic classical dynamics. The probability distributions of the quantum fluctuations of the grand potential and entropy

  56. Laura Tolós, Artur Polls, Angels Ramos, Jürgen Schaffner-Bielich

    The $K^-/K^+$ ratio produced in heavy-ion collisions at GSI energies is studied. The in-medium properties at finite temperature of the hadrons involved are included, paying a special attention to the in-medium properties of antikaons. Using a statistical approach, it is found that the determination of the temperature and chemical potential at freeze-out cond

  57. J. Adam, A. R. Balabekyan, A. S. Danagulyan, N. A. Demekhina

    The analysis results of the isotopic yields for products obtained in reactions of protons at energies 0.66, 1, 8.1GeV with separated tin isotopes are presented. The experimental data are compared in form of reactions of element cross sections for two targets of different isotope compositions. The scaling behaviour have been shown in the dependence of this ra

  58. Robert Pak

    The PHOBOS experiment at RHIC has recorded measurements for Au-Au collisions spanning nucleon-nucleon center-of-mass energies from 19.6 GeV to 200 GeV. Global observables such as elliptic flow and charged particle multiplicity provide important constraints on model predictions that characterize the state of matter produced in these collisions. The nearly 4 p

  59. M. Bialecki, A. Doliwa

    We propose the algebro-geometric mothod of construction of solutions of the discrete KP equation over a finite field. We also perform the corresponding reduction to the finite field version of the discrete KdV equation. We write down formulas which allow to construct multisoliton solutions of the equations starting from vacuum wave functions on arbitrary non

  60. L. Ts. Adzhemyan, J. Honkonen, M. V. Kompaniets, A. N. Vasil&#39;ev

    An improved $\eps$ expansion in the $d$-dimensional ($d > 2$) stochastic theory of turbulence is constructed by taking into account pole singularities at $d \to 2$ in coefficients of the $\eps$ expansion of universal quantities. Effectiveness of the method is illustrated by a two-loop calculation of the Kolmogorov constant in three dimensions.

  61. A. V. Borisov, I. S. Mamaev

    In this paper we present a generalization of the Goryachev-Chaplygin integrable case on a bundle of Poisson brackets, and on Sokolov terms in his new integrable case of Kirchhoff equations. We also present a new analogous integrable case for the quaternion form of rigid body dynamics&#39; equations. This form of equations is recently developed and we can use

  62. David Damanik, Rowan Killip

    We consider Schödinger operators on the half-line, both discrete and continuous, and show that the absence of bound states implies the absence of embedded singular spectrum. More precisely, in the discrete case we prove that if $Δ+ V$ has no spectrum outside of the interval $[-2,2]$, then it has purely absolutely continuous spectrum. In the continuum case we

  63. Werner Westerkamp

    The first part of this thesis proposes a general approach to infinite dimensional non-Gaussian analysis, including the Poissonian case. In particular distribution theory is developed. Using appropriate integral transformations, generalized and test functionals are characterized in terms of holomorphy. Furthermore differential operators, Wick product and chan

  64. Ph. Blanchard, P. Lugiewicz, R. Olkiewicz

    Various physical effects resulting from decoherence are discussed in the algebraic framework. In particular, it is shown that the environment may induce not only classical properties like superselection rules, pointer states or even classical behavior of the quantum system, but, what is more, it also allows the transition from statistical description of infi

  65. Lawrence Ein, Robert Lazarsfeld, Karen E. Smith, Dror Varolin

    We study in this paper some local invariants attached via multiplier ideals to an effective divisor or ideal sheaf on a smooth complex variety. First considered (at least implicitly) by Libgober and by Loeser and Vaquie, these jumping coefficients consist of an increasing sequence of rational numbers beginning with the log canonical threshold of the divisor

  66. Kenji Matsuki

    This is a correction to the afore-mentioned paper in Duke Math. J. vol. 75 (1994), 99-119 by S. Keel, K. Matsuki, and J. McKernan. We completely rewrite Chapter 6 according to the original manuscript of the second author, in order to fix some crucial mistakes pointed out by Dr. Qihong Xie.

  67. Peter Imkeller, Ilya Pavlyukevich

    In this paper we introduce a model which provides a new approach to the phenomenon of stochastic resonance. It is based on the study of the properties of the stationary distribution of the underlying stochastic process. We derive the formula for the spectral power amplification coefficient, study its asymptotic properties and dependence on parameters.

  68. A. B. J. Kuijlaars, W. Van Assche, F. Wielonsky

    We investigate the asymptotic behavior of the polynomials p, q, r of degrees n in type I Hermite-Pade approximation to the exponential function, defined by p(z)e^{-z}+q(z)+r(z)e^{z} = O(z^{3n+2}) as z -> 0. These polynomials are characterized by a Riemann-Hilbert problem for a 3x3 matrix valued function. We use the Deift-Zhou steepest descent method for Riem

  69. Matthias Birkner, Jose Alfredo Lopez Mimbela, Anton Wakolbinger

    We study a semilinear PDE generalizing the Fujita equation whose evolution operator is the sum of a fractional power of the Laplacian and a convex non-linearity. Using the Feynman-Kac representation we prove criteria for asymptotic extinction versus finite time blow up of positive solutions based on comparison with global solutions. For a critical power non-

  70. Jeffrey L. Boersema

    We define united KK-theory for real C*-algebras A and B such that A is separable and B is sigma-unital, extending united K-theory in the sense that KK\crt(\R, B) = K\crt(B). United KK-theory contains real, complex, and self-conjugate KK-theory; but unlike unaugmented real KK-theory, it admits a universal coefficient theorem. For all separable A and B in whic

  71. Rania Wazir

    Let $K$ be a field finitely generated over ${\Q}$, and $A$ an Abelian variety defined over $K$. Then by the Mordell-Weil Theorem, the set of rational points $A(K)$ is a finitely-generated Abelian group. In this paper, assuming Tate&#39;s Conjecture on algebraic cycles, we prove a limit formula for the Mordell-Weil rank of an arbitrary family of Abelian varie

  72. J. Elias

    Let $R$ be a Cohen-Macaulay local ring with maximal ideal $\max$. In this paper we present a procedure for computing the Ratllif-Rush closure of a $\max-$primary ideal $I \subset R$.

  73. Diana A. Mendes, J. Sousa Ramos

    The main purpose of this paper is to present a kneading theory for two-dimensional triangular maps. This is done by defining a tensor product between the polynomials and matrices corresponding to the one-dimensional basis map and fiber map. We also define a Markov partition by rectangles for the phase space of these maps. A direct consequence of these result

  74. Michael Larsen

    Let $A$ be an abelian variety over a number field $K$. If $P$ and $Q$ are $K$-rational points of $A$ such that the order of the reduction of $Q$ divides that of $P$ for all but finitely many primes of the ring of integers of $K$, then there exists a $K$-endomorphism $ϕ$ of $A$ and a positive integer $k$ such that $kQ = ϕ(P)$.

  75. Kazuo Akutagawa, Boris Botvinnik

    We study the Yamabe invariants of cylindrical manifolds and compact orbifolds with a finite number of singularities, by means of conformal geometry and the Atiyah-Patodi-Singer $L^2$-index theory. For an $n$-orbifold $M$ with singularities $Σ_Γ = \{(\check{p}_1, Γ_1), ..., (\check{p}_s, Γ_s)\}$ (where each group $Γ_j<O(n)$ is of finite order), we define and

  76. Vishnu Jejjala, Robert G. Leigh, Djordje Minic

    It was recently pointed out that the physics of a single discrete gravitational extra dimension exhibits a peculiar UV/IR connection relating the UV scale to the radius of the effective extra dimension. Here we note that this non-locality is a manifestation of holography, encoding the correct scaling of the number of fundamental degrees of freedom of the UV

  77. Norma G. Sanchez

    A synthetic report of the advances in the study of classical and quantum string dynamics in curved backgrounds is provided, namely: the new feature of multistring solutions; the effect of a cosmological constant and of spacial curvature on classical and quantum strings; classical splitting of fundamental strings;the general string evolution in constant curva

  78. Christian van Enckevort

    We analyse the moduli spaces of superconformal field theories (SCFTs). For N=2 we find an enhanced moduli space which in geometrical terms corresponds to tori with two independent complex structures. To explain the precise relation with the moduli space of SCFTs on K3 surfaces as described by Aspinwall and Morrison, we discuss some subtleties with the precis

  79. Ramazan Sever, Aytekin Aydemir

    We have calculated the branching ratio and CP asymmetry of B-->X_s +gamma decay within the family--nonuniversal Z&#39; models. We have established certain bounds on the model parameters using the present experimental bounds. We also comment on the role of family--nonuniversality in the hadronic decay modes of the B meson.

  80. Michal Praszalowicz, Andrzej Rostworowski

    We use a simple, instanton motivated, nonlocal chiral quark model to calculate pion Generalized Distribution Amplitudes (GDAs). The nonlocality appears due to the momentum dependence of the constituent quark mass, which we take in a form of a generalized dipole formula. With this choice all calculations can be performed directly in the Minkowski space and th

  81. V. A. Yerokhin, P. Indelicato, V. M. Shabaev

    A complete evaluation of the two-loop self-energy diagrams to all orders in Zαis presented for the ground state of H-like ions with Z\ge 40.

  82. C. Gebert, I. Montvay

    A recurrence scheme is defined for the numerical determination of high degree polynomial approximations to functions as, for instance, inverse powers near zero. As an example, polynomials needed in the two-step multi-boson (TSMB) algorithm for fermion simulations are considered. For the polynomials needed in TSMB a code in C is provided which is easily appli

  83. Mark D. Roberts

    A metric with signature (-+++) can be constructed from a metric with signature (++++) and a double-sided vector field called the line element field. Some of the classical and quantum properties of this vector field are studied.

  84. T. Christodoulakis, C. Helias, P. G. Kevrekidis, I. G. Kevrekidis

    We examine the dynamical behavior of matter coupled to gravity in the context of a linear Klein-Gordon equation coupled to a Friedman-Robertson-Walker metric. The resulting ordinary differential equations can be decoupled, the effect of gravity being traced in rendering the equation for the scalar field nonlinear. We obtain regular (in the massless case) and

  85. Ujjal Debnath, Subenoy Chakraborty

    We investigate the occurrence and nature of a naked singularity in the gravitational collapse of an inhomogeneous dust cloud described by higher dimensional Tolman-Bondi space-time. The naked singularities are found to be gravitationally strong.

  86. Barnabas Poczos, Andras Lorincz

    There is a growing interest in using Kalman-filter models for brain modelling. In turn, it is of considerable importance to represent Kalman-filter in connectionist forms with local Hebbian learning rules. To our best knowledge, Kalman-filter has not been given such local representation. It seems that the main obstacle is the dynamic adaptation of the Kalman

  87. Esra Erdem, Vladimir Lifschitz

    This note is about the relationship between two theories of negation as failure -- one based on program completion, the other based on stable models, or answer sets. Francois Fages showed that if a logic program satisfies a certain syntactic condition, which is now called ``tightness,&#39;&#39; then its stable models can be characterized as the models of its

  88. Dima Grigoriev, Ilia Ponomarenko

    In this paper homomorphic cryptosystems are designed for the first time over any finite group. Applying Barrington&#39;s construction we produce for any boolean circuit of the logarithmic depth its encrypted simulation of a polynomial size over an appropriate finitely generated group.

  89. R. Franco, A. A. Aligia

    We use a mapping of the multiband Hubbard model for $CuO_{3}$ chains in $RBa_{2}Cu_{3}0_{6+x}$ (R=Y or a rare earth) onto a $t-J$ model and the description of the charge dynamics of the latter in terms pf s spinless model, to study the electronic structure of the chains. We briefly review results for the optical conductivity and we calculate the quantum phas

  90. Karen E. Daniels, Christian Beck, Eberhard Bodenschatz

    We present experimental evidence that the motion of point defects in thermal convection patterns in an inclined fluid layer is well-described by Tsallis statistics with an entropic index $q \approx 1.5$. The dynamical properties of the defects (anomalous diffusion, shape of velocity distributions, power law decay of correlations) are in good agreement with t

  91. F. Simon, A. Janossy, T. Feher, F. Muranyi

    The magnetic field dependence of the spin-susceptibility, $χ_{s}$ was measured in the superconducting state of high purity MgB$_{2}$ fine powders below 1.3 T. $χ_{s}$ was determined from the intensity of the conduction electron spin resonance spectra at 3.8, 9.4, and 35 GHz. At the lowest magnetic fields (0.14 T), a gap opens in the density of states at the

  92. F. Penna, P. Tarazona

    We present the theoretical analysis of the steady state currents and density distributions of particles moving with Langevin dynamics, under the effects of an external potential displaced at constant rate. The Dynamic Density Functional (DDF) formalism is used to introduce the effects of the molecular interactions, from the equilibrium Helmholtz free energy

  93. Ernesto P. Borges, Ugur Tirnakli

    The mixing properties (or sensitivity to initial conditions) and relaxation dynamics of the Henon map, together with the connection between these concepts, have been explored numerically at the edge of chaos. It is found that the results are consistent with those coming from one-dimensional dissipative maps. This constitutes the first verification of the sce

  94. M. V. Zyubin, V. A. Kashurnikov

    We propose universal SSE method for simulation of Heisenberg model with arbitrary spin and Bose Hubbard model with interaction. We report on the first calculations of soft-core bosons with interaction by the SSE method. Moreover we develop a simple procedure for increase efficiency of the algorithm. From calculation of integrated autocorrelation times we con

  95. C. Micheletti, V. De Filippis, A. Maritan, F. Seno

    A theoretical model for the folding of proteins containing disulfide bonds is introduced. The model exploits the knowledge of the native state to favour the progressive establishment of native interactions. At variance with traditional approaches based on native topology, not all native bonds are treated in the same way; in particular, a suitable energy term

  96. Keshav N. Shrivastava

    A state with two electrons has a charge of 1/2. The states of three electrons have quasiparticle charge of 4/11 and 5/13, the one with 5 electrons have quasiparticle charges of 4/13 and 6/17. The state with 7 elctrons exhibits quasiparticle charges of 5/17 and 12/17. When spin is reversed, the charge of the three-particle state changes from 4/11 to 7/11. The

  97. Volker C. Weiss, Joseph O. Indekeu

    In recent experiments, a sequence of changes in the wetting state (`wetting transitions&#39;) has been observed upon increasing the temperature in systems consisting of pentane on pure water and of hexane on brine. This sequence of two transitions is brought about by an interplay of short-range and long-range interactions between substrate and adsorbate. In

  98. F. P. Mena, D. van der Marel, M. Faeth, A. A. Menovsky

    Optical properties of the weakly helimagnetic metal MnSi have been determined in the photon energy range from 2 meV to 4.5 eV using the combination of grazing incidence reflectance at 80 degrees (2 meV to 0.8 eV) and ellipsometry (0.8 to 4.5 eV). As the sample is cooled below 100 K the effective mass becomes strongly frequency dependent at low frequencies, w

  99. Amnon Buxboim, Avraham Schiller

    The linear and nonlinear transport properties of the single-electron transistor at the degeneracy point are investigated for the case of weak single-mode tunnel junctions. Two opposing scenarios are considered, distinguished by whether or not electrons can propagate coherently between the two tunnel junctions. Each of these two scenarios corresponds to the r

  100. Tai-Kai Ng

    Within bosonization theory we introduce in this paper a new definition of &#34;quasi-particles&#34; for interacting fermions at arbitrary space dimenions. In dimensions higher than one we show that the constructed quasi-particles are consistent with quasi-particle descriptions in Landau Fermi liquid theory whereas in one-dimension the quasi-particles&#34; ar