February 2002 arXiv papers — page 17

Sebastien Majerowicz, Monique Arnaud, David Lumb, Doris M. Neumann

We present the follow-up of two galaxy clusters from the Bright and Southern SHARC surveys observed with the XMM-Newton satellite. We studied the galaxy cluster RX J1120.1+4318 which seems to be a relaxed cluster at high redshift according to its surface brightness profile and to its temperature profile which is flat up to 950 kpc. Its mean temperature is me

Ping He, Li-Zhi Fang

We investigate the constraint on the abundance of primordial black holes (PBHs) and the spectral index $n$ of primeval density perturbations given by the ionizing photon background at the epoch of reionization. Within the standard inflationary cosmogony, we show that the spectral index $n$ of the power-law power spectrum of primeval density perturbations sho

Chuan-Hung Chen, C. Q. Geng, J. N. Ng

We study the T violating effects in the baryonic decays of $Λ_b\toΛl^+l^- (l=e ,μ)$ with polarized $Λ$. We show that the transverse $Λ$ polarizations in these baryonic decays could be as large as 50% in CP violating theories beyond the standard model such as the SUSY models, which can be tested in various future hadron colliders.

Jessica L. Rosenberg, Stephen E. Schneider

We present a study of the expected properties of the low redshift damped Lyman-alpha absorber population determined from a sample of HI-selected galaxies in the local universe. Because of a tight correlation between the HI mass and HI cross-section, which we demonstrate spans all galaxy types, we can use our HI-selected sample to predict the properties of th

J. B. Marston, J. O. Fjaerestad, Asle Sudbo

We present numerical evidence for the existence of a staggered flux (SF) phase in the half-filled two-leg t-U-V-J ladder, with true long-range order in the counter-circulating currents. The density-matrix renormalization-group (DMRG) / finite-size scaling approach, generalized to describe complex-valued Hamiltonians and wavefunctions, is employed. The SF pha

Nima Arkani-Hamed, Andrew G. Cohen, Thomas Gregoire, Jay G. Wacker

Recently, a new class of realistic models for electroweak symmetry breaking have been constructed, without supersymmetry. These theories have naturally light Higgs bosons and perturbative new physics at the TeV scale. We describe these models in detail, and show that electroweak symmetry breaking can be triggered by a large top quark Yukawa coupling. A rich

Oleg Lunin, Samir D. Mathur

For the 2-charge extremal holes in string theory we show that the Bekenstein entropy obtained from the area of the stretched horizon has a statistical interpretation as a `coarse graining entropy': different microstates give geometries that differ near r=0 and the stretched horizon cuts off the metric at r=b where these geometries start to differ.

A. D. Jackson, G. M. Kavoulakis

We calculate the dispersion relation associated with a solitary wave in a quasi-one-dimensional Bose-Einstein condensate of atoms confined in a harmonic, cylindrical trap in the limit of weak and strong interactions. In both cases, the dispersion relation is linear for long wavelength excitations and terminates at the point where the group velocity vanishes.

Tianjun Li, Liao Wei

We show that the desirable weak mixing angle sin^2 theta_W = 0.2312 at m_Z scale can be generated naturally in the SU(3)_C times SU(3) model on M^4 times S^1 / (Z_2 times Z_2') where the gauge symmetry SU(3) is broken down to SU(2)_L times U(1)_Y by orbifold projection. For a supersymmetric model with a TeV scale extra dimension, the SU(3) unification sc

Christian W. Bauer, Sean Fleming, Dan Pirjol, Ira Z. Rothstein

In this paper we show how gauge symmetries in an effective theory can be used to simplify proofs of factorization formulae in highly energetic hadronic processes. We use the soft-collinear effective theory, generalized to deal with back-to-back jets of collinear particles. Our proofs do not depend on the choice of a particular gauge, and the formalism is app

Alexander Friedland, Andrei Gruzinov

We reexamine the transition magnetic moment solution to the solar neutrino problem. We argue that the absence of large time variations in the Super-Kamiokande rate provides strong evidence against spin-flavor flip in the solar convective zone. Spin-flavor flip could, however, occur in the primordial magnetic field in the radiative zone. We compute the longes

Thomas M. Brown, Henry C. Ferguson, Robert W. O'Connell, Raymond G. Ohl

We present far-UV spectroscopy of the giant elliptical galaxy NGC 1399, obtained with the Far Ultraviolet Spectroscopic Explorer. Of all quiescent ellipticals, NGC 1399 has the strongest known ``UV upturn'' -- a sharp spectral rise shortward of 2500 A. It is now well-established that this emission comes from hot horizontal branch (HB) stars and their

Robert B. Meyer, Robert A. Pelcovits

We explore the possibility that the large electroclinic effect observed in ferroelectric liquid crystals arises from the presence of an ordered array of disclination lines and walls. If the spacing of these defects is in the subvisible range, this modulated phase would be similar macroscopically to a smectic A phase. The application of an electric field dist

I. Jack, D. R. T. Jones, R. Wild

We explore, in the context of the MSSM generalised to admit massive neutrinos, an extension of the Anomaly Mediated Supersymmetry Breaking solution for the soft scalar masses to incorporate Fayet-Iliopoulos D-terms. The slepton mass problem characteristic of the scenario is resolved, and the fermion mass hierarchy is explained via the Froggatt-Nielsen mechan

Nicolas Andruskiewitsch, Matias Graña

A fundamental step in the classification of finite-dimensional complex pointed Hopf algebras is the determination of all finite-dimensional Nichols algebras of braided vector spaces arising from groups. The most important class of braided vector spaces arising from groups is the class of braided vector spaces (CX, c^q), where C is the field of complex number

Alejandro Corichi, Jeronimo Cortez, Hernando Quevedo

Linear free field theories are one of the few Quantum Field Theories that are exactly soluble. There are, however, (at least) two very different languages to describe them, Fock space methods and the Schroedinger functional description. In this paper, the precise sense in which the two representations are related is reviewed. Several properties of these repr

Didier Poilblanc, D. J. Scalapino

Using numerical techniques, the diagonal and off-diagonal superconducting one-electron Green's functions are calculated for a two-dimensional (2D) t-J model on a periodic 32-site cluster at low doping. From these Green's functions, the momentum and frequency dependence of the pairing gap $Δ({\bf k}, ω)$ are extracted. It has $d_{x^2-y^2}$ symmetry an

Werner Kerler

We clarify the questions rised by a recent example of a lattice Dirac operator found by Chiu. We show that this operator belongs to a class based on the Cayley transformation and that this class on the finite lattice generally does not admit a nonvanishing index, while in the continuum limit, due to operator properties in Hilbert space, this defect is no lon

Cecilia Albertsson, Ulf Lindstrom, Maxim Zabzine

We consider the N=1 supersymmetric two-dimensional non-linear sigma model with boundaries and nonzero B-field. By analysing the appropriate currents we describe the full set of boundary conditions compatible with N=1 superconformal symmetry. Using this result the problem of finding a correct action is discussed. We interpret the supersymmetric boundary condi

Piotr Jaranowski, Gerhard Schäfer

For binary black holes the lapse function corresponding to the Brill-Lindquist initial value solution for uncharged black holes is given in analytic form under the maximal slicing condition. In the limiting case of very small ratio of mass to separation between the black holes the surface defined by the zero value of the lapse function coincides with the min

Sumithra Sankararaman, Gautam I. Menon, P. B. Sunil Kumar

We study the linearized hydrodynamics of a two-component fluid membrane near a repulsive wall, via a model which incorporates curvature- concentration coupling as well as hydrodynamic interactions. This model is a simplified version of a recently proposed one [J.-B. Manneville et al. Phys. Rev. E, 64, 021908 (2001)] for non-equilibrium force-centres embedded

Matthias R Gaberdiel, Terry Gannon

The boundary states for a certain class of WZW models are determined. The models include all modular invariants that are associated to a symmetry of the unextended Dynkin diagram. Explicit formulae for the boundary state coefficients are given in each case, and a number of properties of the corresponding NIM-reps are derived.

V. E. Adler, A. I. Bobenko, Yu. B. Suris

A classification of discrete integrable systems on quad-graphs, i.e. on surface cell decompositions with quadrilateral faces, is given. The notion of integrability laid in the basis of the classification is the three-dimensional consistency. This property yields, among other features, the existence of the discrete zero curvature with a spectral parameter. Fo

M. Ouchi, K. Shimasaku, H. Furusawa, M. Miyazaki

We report on early results from deep and wide-field narrow-band imaging on a 543 arcmin^2 area of the Subaru Deep Field. We find 87 Lya emitters (LAEs) at z=4.86(+/-0.03) which are photometrically selected by a combination of two broad bands (R and i') and one narrow band (NB711; 7126A FWHM=73A). We derive the luminosity functions (LFs) of the LAEs at Ly

Alexander Burinskii, Sergi R. Hildebrandt

We show that the Bronnikov theorem on the nonexistence of regular electrically charged black holes can be circumvented. In the frame of nonlinear electrodynamics, we present the exact regular black hole solutions of a hybrid type. They are electrically charged, but contain a `dual' core confining a polarization of magnetic charges. The considered example

Jacob D. Bekenstein, Gilad Gour

What is the nature of the energy spectrum of a black hole ? The algebraic approach to black hole quantization requires the horizon area eigenvalues to be equally spaced. As stressed long ago by by Mukhanov, such eigenvalues must be exponentially degenerate with respect to the area quantum number if one is to understand black hole entropy as reflecting degene

D. V. Khveshchenko, A. G. Yashenkin

We study the behavior of two-dimensional Dirac fermions in the presence of a static long-range-correlated random vector potential. By applying an exact path integral representation for the propagator of a spinor particle we obtain asymptotics of the gauge invariant spectral function and the correlation function of the local density of states, both in the bal

William E. Baylis

In contrast to formulations of the Dirac theory by Hestenes and by the current author, the formulation recently presented by W. P. Joyce [J. Phys. A: Math. Gen. 34 (2001) 1991--2005] is equivalent to the usual Dirac equation only in the case of vanishing mass. For nonzero mass, solutions to Joyce's equation can be solutions either of the Dirac equation i

Dominik Janzing, Thomas Beth

Even if a logical network consists of thermodynamically reversible gate operations, the computation process may have high dissipation rate if the gate implementation is controlled by external clock signals. It is an open question whether the global clocking mechanism necessarily envolves irreversible processes. However, one can show that it is not possible t

Karl Gerd H. Vollbrecht, Michael M. Wolf

We discuss conditional Renyi and Tsallis entropies for bipartite quantum systems of finite dimension. We investigate the relation between the positivity of conditional entropies and entanglement properties. It is in particular shown that any state having a negative conditional entropy with respect to any value of the entropic parameter is distillable since i

Elias Zafiris

An observable effects a schematization of the Quantum event structure by correlating Boolean algebras picked by measurements with the Borel algebra of the real line. In a well-defined sense Boolean observables play the role of coordinatizing objects in the Quantum world, by picking Boolean figures and subsequently opening Boolean windows for the perception o

G. Abramson, V. M. Kenkre

We present a model of the infection of Hantavirus in deer mouse, Peromyscus maniculatus, based on biological observations of the system in the North American Southwest. The results of the analysis shed light on relevant observations of the biological system, such as the sporadical disappearance of the infection, and the existence of foci or ``refugia'&#3

Y. Peng, U. H. E. Hansmann

Helix-coil transitions in poly-alanine molecules of length 10 are studied by multicanonical Monte Carlo simulations. The solvation effects are included by either a distance-dependent dielectric permittivity or by a term that is proportional to the solvent-accessible surface area of the peptide. We found a strong dependence of the characteristics of the helix

M. Y. Su, S. Carter, M. S. Sherwin, A. Huntington

Driving a double-quantum-well excitonic intersubband resonance with a terahertz (THz) electric field of frequency ω_{THz} generated terahertz optical sidebands ω=ω_{THz}+ω_{NIR} on a weak NIR probe. At high THz intensities, the intersubband dipole energy which coupled two excitons was comparable to the THz photon energy. In this strong-field regime the sideb

Jagtar S. Hunjan, Ram Ramaswamy

We apply a recently introduced method for global optimization to determine the ground state energy and configuration for model metallic clusters. The global minimum for a given N-atom cluster is found by following the damped dynamics of the N particle system on an evolving potential energy surface. In this application, the time dependent interatomic potentia

A. Nogga, A. Kievsky, H. Kamada, W. Gloeckle

The bound states of $^3$H and $^3$He have been calculated using the Argonne $v_{18}$ plus the Urbana three-nucleon potential. The isospin $T=3/2$ state have been included in the calculations as well as the $n$-$p$ mass difference. The $^3$H-$^3$He mass difference has been evaluated through the charge dependent terms explicitly included in the two-body potent

Thomas D. Cohen, Boris A. Gelman

Nucleon-nucleon scattering observables are considered in the context of the large $N_c$ limit of QCD for initial states with moderately high momenta ($p \sim N_c$). The scattering is studied in the framework of the time-dependent mean-field approximation. We focus on the dependence of those observables on the spin and isospin of the initial state which may b

A. S. Botvina

It is shown that the chemical equilibrium condition of the system can be unambiguously identified by analyzing the isospin evolution of fragments produced in nuclear multifragmentation process. As far as the chemical equilibrium is established, the isotope production can be used for finding properties of nuclear matter and fragments in the freeze-out volume,

D. V. Vinnik, R. Alkofer, S. M. Schmidt, S. A. Smolyansky

We derive quantum kinetic equations for fermion and boson production starting from a phi^4 Lagrangian with minimal coupling to fermions. Decomposing the scalar field into a mean-field part and fluctuations we obtain spontaneous pair creation driven by a self-interacting strong background field. The produced fermion and boson pairs are self-consistently coupl

T. Hirano, K. Tsuda

We investigate the effect of early chemical freeze-out on radial and elliptic flow by using a fully three dimensional hydrodynamic model. We find that the time evolution of temperature and the thermal freeze-out temperature dependence of average radial flow are different from the results by using a conventional hydrodynamic model in which chemical equilibriu

T. Falter, U. Mosel

We present a way to account for coherence length effects in a semi-classical transport model. This allows us to describe photo- and electroproduction at large nuclei (A>12) and high energies using a realistic coupled channel description of the final state interactions that goes far beyond simple Glauber theory. We show that the purely absorptive treatment of

B. M. K. Nefkens, J. W. Price

The neutral decay modes of the eta meson are reviewed. The most recent results obtained with the Crystal Ball multiphoton detector at BNL are incorporated. This includes a new, precise result for the slope parameter alpha of the Dalitz plot in eta -> 3pi0 decay and a new, lower branching ratio for eta -> pi0 gamma gamma which is consistent with chiral pertur

B. M. K. Nefkens, S. Prakhov, A. Starostin

We present preliminary results on the cross sections and Dalitz-plot densities for the process pi- p -> pi0 pi0 n from threshold to p(pi)=750 MeV/c as well as for K- p -> pi0 pi0 Lambda and K- p -> pi0 pi0 Sigma0 at p(K)=520 to 750 MeV/c. We have found that sigma(tot)(pi- p -> pi0 pi0 n) ~= 2sigma(tot)(K- p -> pi0 pi0 Lambda). The pi0 pi0 n Dalitz plots are

B. M. K. Nefkens

We will present some thoughts on the following topics: 1. Major highlights in the history of strong interactions such as isospin, the pion, SU(3), quarks, the color degree of freedom, QCD. 2. Topics of high current interest such as quark confinement, the origin of mass, the search for the gluon degrees of freedom, chiral symmetry, flavor symmetry, regulariti

P. Szlachetka, K. Grygiel, M. Misiak

A pair (A,B) of interacting oscillators treated as a master system sending signals to its slave copy (a,b) through two communication channels A-->a and B-->b is considered. The effect of non-simultaneous (two-time) synchronization of the pairs (a,A) and (b,B) is demonstrated with the help of coupled Kerr oscillators producing hyperchaos. An individual pair,

J. A. Gonzalez, L. I. Reyes, J. J. Suarez, L. E. Guerrero

We investigate explicit functions that can produce truly random numbers. We use the analytical properties of the explicit functions to show that certain class of autonomous dynamical systems can generate random dynamics. This dynamics presents fundamental differences with the known chaotic systems. We present realphysical systems that can produce this kind o

Cristian S. Calude, Michael J. Dinneen, Chi-Kou Shu

A Chaitin Omega number is the halting probability of a universal Chaitin (self-delimiting Turing) machine. Every Omega number is both computably enumerable (the limit of a computable, increasing, converging sequence of rationals) and random (its binary expansion is an algorithmic random sequence). In particular, every Omega number is strongly non-computable.

Brian P. Ingalls, Eduardo D. Sontag, Yuan Wang

In previous work the notion of input to state stability (ISS) has been generalized to systems with outputs, yielding a number of useful concepts. When considering a system whose output is to be kept small (i.e. an error output), the notion of input to output stability (IOS) arises. Alternatively, when considering a system whose output is meant to provide inf

Dorin Ervin Dutkay

Motivated by wavelet analysis, we prove that there is a one-to-one correspondence between the following data: Solutions to $R(h)=h$ where $R$ is a certain non-positive Ruelle transfer operator; Operators that intertwine a certain class of representations of the $C^*$-algebra $\mathfrak{A}_N$ on two unitary generators $U$, $V$ subject to the relation $$UVU^{-

Michel Deza, Viacheslav Grishukhin

Non-rigidity degree of a lattice $L$, nrd$L$, is dimension of the L-type domain to which $L$ belongs. We complete here the table of nrd's of all root lattices and their duals; namely, the hardest remaining case of $D_n^*$, and the case of $E_7^*$ are decided. We describe explicitly the $L$-type domain ${\cal D}(D_n^*)$, $n \ge 4$. For $n$ odd, it is a no

E. Ragoucy

We present a construction of integrable hierarchies without or with boundary, starting from a single R-matrix, or equivalently from a ZF algebra. We give explicit expressions for the Hamiltonians and the integrals of motion of the hierarchy in term of the ZF algebra. In the case without boundary, the integrals of motion form a quantum group, while in the cas

Ilka Agricola

Given a reductive homogeneous space M=G/H endowed with a naturally reductive metric, we study the one-parameter family of connections joining the canonical and the Levi-Civita connection (t=0, 1/2). We show that the Dirac operator D^t corresponding to t=1/3 is the so-called ``cubic'' Dirac operator recently introduced by B. Kostant, and derive the fo

Aicke Hinrichs, J. Wenzel

A Banach space X has the average distance property (ADP) if there exists a unique real number r such that for each positive integer n and all x_1,...,x_n in the unit sphere of X there is some x in the unit sphere of X such that 1/n \sum_{k=1}^n ||x_k-x|| = r. We show that l_p does not have the average distance property if p>2. This completes the study of the

Selma Altınok, Gavin Brown, Miles Reid

Explicit birational geometry of 3-folds represents a second phase of Mori theory, going beyond the foundational work of the 1980s. This paper is a tutorial and colloquial introduction to the explicit classification of Fano 3-folds (Q-Fano 3-folds), a subject that we hope is nearing completion. With the intention of remaining accessible to beginners in algebr

Eric T. Matsui

We present an equivariant Liapunov stability criterion for dynamical systems with symmetry. This result yields a simple proof of the energy-momentum-Casimir stability analysis of relative equilibria of equivariant Hamiltonian systems.

Andrei Mudrov

We introduce triples of associative algebras as a tool for building solutions to the Yang-Baxter equation. It turns out that the class of R-matrices thus obtained is related to a Hecke-like condition, which is formulated for associative algebras with symmetric cyclic inner product. R-matrices for a subclass of the $A_n$-type Belavin-Drinfel'd triples are

I. Filippov, S. Pinsky

We consider the $N=(1,1)$ SYM theory that is obtained by dimensionally reducing SYM theory in 2+1 dimensions to 1+1 dimensions and discuss soft supersymmetry breaking. We discuss the numerical simulation of this theory using SDLCQ when either the boson or the fermion has a large mass. We compare our result to the pure adjoint fermion theory and pure adjoint

Nail R. Khusnutdinov, Sergey V. Sushkov

The ground state energy of the massive scalar field with non-conformal coupling $ξ$ on the short-throat flat-space wormhole background is calculated by using zeta renormalization approach. We discuss the renormalization and relevant heat kernel coefficients in detail. We show that the stable configuration of wormholes can exist for $ξ> 0.123$. In particular

P. Bozhilov

New exact string solutions in non-constant background fields are found and it is shown that some of them are compatible with the boundary conditions for the open string - D-brane system. Extension of the constraint algebra is proposed and discussed.

Andrej Arbuzov, Andrzej Czarnecki, Andrei Gaponenko

O(alpha^2 ln^2(m_mu/m_e)) QED corrections to the electron spectrum and angular distribution in muon decay are evaluated. Impact on the determination of Michel parameters is estimated. Current theoretical uncertainty in the muon decay distributions is discussed.

L. Everett, G. L. Kane, S. F. King, S. Rigolin

We explore supersymmetric Type I string-motivated three-family scenarios in which the Standard Model is embedded within two sets of intersecting D branes with U(1)-extended Pati-Salam gauge groups. We study a model inspired by the Shiu-Tye Type IIB orientifold, in which a three-family scenario is obtained by assuming that the gauge symmetry breaking takes pl

Marek Karliner, Harry J. Lipkin

We discuss the seemingly contradictory constraints of simultaneously preserving the SU(3)-symmetric Cabibbo description of the weak vector baryon matrix elements, accounting for SU(3) flavor symmetry breaking and describing the observed violation of the Gottfried Sum Rule. We try to construct a simple model that will satisfy these constraints and use it to e

M. Oertel, M. Buballa

The structure of the phase diagram of strongly interacting matter at moderate densities is calculated within a 3-flavor NJL-type quark model with realistic quark masses. We focus on the influence of the selfconsistently determined effective strange quark mass on the color-flavor unlocking phase transition.

Marie-Bernadette Causse

The radiative decay of neutrino,such as (\bar{ν_τ}: \longrightarrow: ν_μ+γ), in the minimal supersymmetric standard model with right-handed neutrinos (MSSMRN) and in the (SU(5)) grand unified theory with right-handed neutrinos((SU(5)RN))model is examined.In these models,the transition magnetic moment of neutrino is directly proportional to the neutrino mass.

F. V. Tkachov

Computer implementation of sophisticated algorithms for physics applications is greatly facilitated by the new generation of component-oriented SD technologies pioneered by Wirth's Oberon and embraced by the software industry (Sun's Java and Microsoft's C#). In a stark contrast with the deeply flawed C++, the Oberon technologies (specifically, th

L. A. Caron, H. Kröger, G. Melkonyan, X. Q. Luo

We construct an effective low-energy Hamiltonian from the classical action via Monte Carlo with importance sampling. We use Monte Carlo (i) to compute matrix elements of the transition amplitude and (ii) to construct stochastically a basis. The MC Hamiltonian allows to obtain energies and wave functions of low-lying states. It allows also to compute thermody

T. Byrnes, P. Sriganesh, R. J. Bursill, C. J. Hamer

The massive Schwinger model is studied, using a density matrix renormalisation group approach to the staggered lattice Hamiltonian version of the model. Lattice sizes up to 256 sites are calculated, and the estimates in the continuum limit are almost two orders of magnitude more accurate than previous calculations. Coleman's picture of `half-asymptotic&#

L3 Collaboration

The process e+ e- -> n gamma with n>=2 is studied at centre-of-mass energies ranging from \root(s)=192 to 208 GeV. The data sample corresponds to a total integrated luminosity of 427 1/pb. The total and differential cross sections are found to be in agreement with the QED expectations. Using all the data collected with the L3 detector above the Z pole, limit

David W. Hertzog

The E821 experiment at Brookhaven National Laboratory is designed to measure the muon magnetic anomaly, a_mu, to an ultimate precision of 0.4 parts per million (ppm). Because theory can predict a_mu to 0.6 ppm, and ongoing efforts aim to reduce this uncertainty, the comparison represents an important and sensitive test of new physics. At the time of this Wor

G. Giacomelli, B. Poli

We review some of the recent experimental results obtained at high-energy colliders with emphasis on LEP and SLC results.

Michele Vallisneri

In the next few years, the first detections of gravity-wave signals using Earth-based interferometric detectors will begin to provide precious new information about the structure and dynamics of compact bodies such as neutron stars. The intrinsic weakness of gravity-wave signals requires a proactive approach to modeling the prospective sources and anticipati

Marc Mars, Jose M. M. Senovilla

We study the stationary and axisymmetric non-convective differentially rotating perfect-fluid solutions of Einstein's field equations admitting one conformal symmetry. We analyse the two inequivalent Lie algebras not exhaustively considered in Mars and Senovilla, 1994, and show that the general solution for each Lie algebra depends on one arbitrary funct

J. Podolsky

A physical interpretation of the C-metric with a negative cosmological constant $Λ$ is suggested. Using a convenient coordinate system it is demonstrated that this class of exact solutions of Einstein's equations describes uniformly accelerating (possibly charged) black holes in anti-de Sitter universe. Main differences from the analogous de Sitter case

W. Drabent, J. Maluszynski, P. Pietrzak

This paper introduces a framework of parametric descriptive directional types for constraint logic programming (CLP). It proposes a method for locating type errors in CLP programs and presents a prototype debugging tool. The main technique used is checking correctness of programs w.r.t. type specifications. The approach is based on a generalization of known

Patrik O. Hoyer

Non-negative sparse coding is a method for decomposing multivariate data into non-negative sparse components. In this paper we briefly describe the motivation behind this type of data representation and its relation to standard sparse coding and non-negative matrix factorization. We then give a simple yet efficient multiplicative algorithm for finding the op

Kunal K. Das, G. John Lapeyre, Ewan M. Wright

We study the quantum dynamics of a one-dimensional gas of impenetrable bosons on a ring, and investigate the interference that results when an initially trapped gas localized on one side of the ring is released, split via an optical-dipole grating, and recombined on the other side of the ring. Large visibility interference fringes arise when the wavevector o

Jian-Xin Zhu

Both the differential tunneling conductance and the surface local density of states (LDOS) of a [110]-oriented high-temperature superconductor in the pseudogap (PG) regime are studied theoretically. As a competing candidate for the mechanism of PG state, the charge-density wave (CDW), spin-density wave (SDW), $d$-density wave (DDW), and d-wave superconductin

P. E. Kornilovitch

A family of exact sum rules for the one-polaron spectral function in the low-density limit is derived. An algorithm to calculate energy moments of arbitrary order of the spectral function is presented. Explicit expressions are given for the first two moments of a model with general electron-phonon interaction, and for the first four moments of the Holstein p

Massimo Rontani, Guido Goldoni, Franca Manghi, Elisa Molinari

We study electron molecules in realistic vertically coupled quantum dots in a strong magnetic field. Computing the energy spectrum, pair correlation functions, and dynamical form factor as a function of inter-dot coupling via diagonalization of the many-body Hamiltonian, we identify structural transitions between different phases, some of which do not have a

S. Komineas, N. Papanicolaou

We present a calculation of a solitary wave propagating along a cylindrical Bose-Einstein trap, which is found to be a hybrid of a one-dimensional (1D) soliton and a three-dimensional (3D) vortex ring. The calculated energy-momentum dispersion exhibits characteristics similar to those of a mode proposed sometime ago by Lieb within a 1D model, as well as some

S. Sivasubramanian, A. Widom, Y. N. Srivastava

The Landau-Lifshitz-Gilbert damping coefficient employed in the analysis of spin wave ferromagnetic resonance is related to the electrical conductivity of the sample. The changing magnetization (with time) radiates electromagnetic fields. The electromagnetic energy is then absorbed by the sample and the resulting heating effect describes magnetic dissipative

V. N. Golovach, M. E. Portnoi

We predict a double-resonant feature in the magnetic field dependence of the phonon-mediated longitudinal conductivity $σ_{xx}$ of a two-subband quasi-two-dimensional electron system in a quantizing magnetic field. The two sharp peaks in $σ_{xx}$ appear when the energy separation between two Landau levels belonging to different size-quantization subbands is

P. E. Berche, C. Chatelain, B. Berche, W. Janke

We investigate by Monte Carlo simulations the critical properties of the three-dimensional bond-diluted Ising model. The phase diagram is determined by locating the maxima of the magnetic susceptibility and is compared to mean-field and effective-medium approximations. The calculation of the size-dependent effective critical exponents shows the competition b

Tom Busche, Lorenz Bartosch, Peter Kopietz

We calculate the single-particle spectral function A (k, omega) of a one-dimensional Luttinger liquid by means of a functional renormalization group (RG) approach. Given an infrared energy cutoff Lambda = Lambda_0 e^{- l}, our approach yields the spectral function in the scaling form, A_Λ (k_F + p, omega) = tau Z_l tilde{A}_l (p xi, omega tau), where k_F is

R. Alberich, J. Miro-Julia, F. Rossello

We investigate the structure of the Marvel Universe collaboration network, where two Marvel characters are considered linked if they jointly appear in the same Marvel comic book. We show that this network is clearly not a random network, and that it has most, but not all, characteristics of "real-life" collaboration networks, such as movie actors or

Vijay Shenoy, Ashutosh Sharma

Dynamics and morphology of hole growth in a film of power hardening viscoplastic solid (yield stress ~ [strain-rate]^n) is investigated. At short-times the growth is exponential and depends on the initial hole size. At long-times, for n > 1/3, the growth is exponential with a different exponent. However, for n < 1/3, the hole growth slows; the hole radius ap

S. Guillon, P. Vasilopoulos, C. M. Van Vliet

Electrical conduction is studied along parabolically confined quasi-one dimensional channels, in the framework of a revised linear-response theory, for elastic scattering. For zero magnetic field an explicit multichannel expression for the conductance is obtained that agrees with those of the literature. A similar but new multichannel expression is obtained

P. -E. Roche, B. Doucot

We study the full probability distribution of the charge transmitted through a mesoscopic diffusive conductor during a measurement time T. We have considered a semi-classical model, with an exclusion principle in a discretized single-particle phase-space. In the large T limit, numerical simulations show a universal probability distribution which agrees very

Mark Levene, Trevor Fenner, George Loizou, Richard Wheeldon

Recently several authors have proposed stochastic models of the growth of the Web graph that give rise to power-law distributions. These models are based on the notion of preferential attachment leading to the ``rich get richer&#39;&#39; phenomenon. However, these models fail to explain several distributions arising from empirical results, due to the fact th

G. Handler, L. A. Balona, R. R. Shobbrook, C. Koen

We have discovered both intermediate-order gravity mode and low-order pressure mode pulsation in the same star, HD 209295. It is therefore both a Gamma Doradus and a Delta Scuti star, which makes it the first pulsating star to be a member of two classes. The star is a single-lined spectroscopic binary with an orbital period of 3.10575 d and an eccentricity o

V. Mainieri, J. Bergeron, P. Rosati, G. Hasinger

We present the results of the X-ray spectral analysis of the deep survey obtained with the XMM-Newton observatory on the Lockman Hole. The X-ray data and the cumulative source counts were reported by Hasinger et al. (2001). Our sample contains 104 sources with a count limit of 70 of which 55 have redshift identification. The redshift distribution peaks at z

Jacco Vink, Johan Bleeker, Jelle Kaastra, Kurt van der Heyden

We present an analysis of the X-ray emission of the supernova remnant MSH14-63, which was partially covered by four observations with XMM-Newton. The detection of Fe K emission at 6.4 keV, and the lack of spatial correlation between hard X-ray and radio emission is evidence against a dominant X-ray synchrotron component. We argue that the hard X-ray continuu

F. Daigne, P. Goldoni, P. Ferrando, A. Goldwurm

The XMM-Newton X-ray observatory performed a pointed observation of the bursting pulsar GRO J1744-28 in April 2001 for about 10 ks during a program devoted to the scan of the Galactic center region. After the discovery of this source by BATSE in December 1995 during a very active bursting phase, it has been in quiescence since April 1997. We present here the

G. Bertin, L. Ciotti, M. Del Principe

We start by studying a small set of objects characterized by photometric profiles that have been pointed out to deviate significantly from the standard R^{1/4} law. For these objects we confirm that a generic R^{1/n} law, with n a free parameter, can provide superior fits (the best-fit value of n can be lower than 2.5 or higher than 10), better than those th

Johan Bleeker, Jacco Vink, Kurt van der Heyden, Dick Willingale

In this paper we present recent image and spectral data of Cas-A obtained with XMM-Newton and BeppoSAX. Analysis of the hard X-ray continuum does not support an interpretation of the hard X-radiation as synchrotron emission produced in the primary shock, non-thermal Bremsstrahlung is a plausible alternative. Moreover, a recent 500 kilosecond deep observation

A. De Rosa, A. C. Fabian, L. Piro, D. R. Ballantyne

The ionized disc reflection model of Ross & Fabian is applied to a sample of five Seyfert 1 galaxies observed by BeppoSAX. Good fits were obtained for all the objects in the sample. NGC 4051 and Mkn 335 (usually classified as NLSy 1s) show evidence of a highly ionized accretion disc (xi ~ 350 erg cm s^{-1} and xi \~ 800 erg cm s^{-1}). While NGC 3783 seems t

J. Rodriguez, Ph. Durouchoux, I. F. Mirabel, Y. Ueda

We analyze a set of three RXTE Target of Opportunity observations of the Galactic microquasar GRS 1915+105, observed on April 2000, during a multi-wavelength campaign. During the three observations, a strong, variable low frequency (2-9 Hz) quasi periodic oscillation (hereafter QPO), often referred to as the ubiquitous QPO, is detected together with its firs

V. S. Niemela, P. Massey, G. Testor, S. Gimenez Benitez

We present a study of optical spectra of the Wolf--Rayet star AzV 336a (= SMC WR7) in the Small Magellanic Cloud. Our study is based on data obtained at several Observatories between 1988 and 2001. We find SMC WR7 to be a double lined WN+O6 spectroscopic binary with an orbital period of 19.56 days. The radial velocities of the He absorption lines of the O6 c

Smita Mathur, Belinda Wilkes, Himel Ghosh

We report on Chandra observations of three quasars SDSSP J083643+005453, SDSSP J103027+052455, and SDSSP J130608+035626 at redshifts 5.82, 6.28 and 5.99 respectively. All the three sources are clearly detected in the X-ray band, up to rest frame energies of ~55 keV. These observations demonstrate the unprecedented sensitivity of Chandra to detect faint sourc

M. Beattie

This paper studies the duals of some finite dimensional pointed Hopf algebras, with abelian group of grouplikes, over an algebraically closed field of characteristic 0, which are either Radford biproducts or else nontrivial liftings of a biproduct.