July 2003 arXiv papers — page 4

Riazuddin

Phenomenological implications of neutrino oscillations implied by recent experimental data on pattern of neutrino mass matrix are disscussed. It is shown that it is possible to have a neutrino mass matrix which shows approximate flavor symmetry; the neutrino mass differences arise from flavor violation in off-diagonal Yukawa couplings. Two modest extensions

Petr Jizba, Toshihico Arimitsu

Despite recent claims we argue that Renyi's entropy is an observable quantity. It is shown that, contrary to popular belief, the reported domain of instability for Renyi entropies has zero measure (Bhattacharyya measure). In addition, we show the instabilities can be easily emended by introducing a coarse graining into an actual measurement. We also clea

Animesh Datta, Biplab Ghosh, A. S. Majumdar, N. Nayak

We consider a realistic model for the one-atom micromaser consisting of a cavity maintained in a steady state by the streaming of two-level Rydberg atoms passing one at a time through it. We show that it is possible to monitor the robust entanglement generated between two successive experimental atoms passing through the cavity by the control decoherence par

Aftab Alam, Abhijit Mookerjee

We present here an augmented space recursive technique in the k-representation which include diagonal, off-diagonal and the environmental disorder explicitly : an analytic, translationally invariant, multiple scattering theory for phonons in random binary alloys.We propose the augmented space recursion (ASR) as a computationally fast and accurate technique w

Robert V. Harlander, Matthias Steinhauser

Supersymmetric QCD corrections to the gluonic production and decay rate of a CP-even Higgs boson are evaluated at next-to-leading order. To this aim, we derive an effective Lagrangian for the gluon-Higgs coupling. We show that a consistent calculation requires the inclusion of gluino effects, in contrast to what has been done previously. The supersymmetric c

Minoru Eto, Norisuke Sakai

A class of exactly solvable models of domain walls are worked out in D=4 ${\cal N}=1$ supergravity. We develop a method to embed globally supersymmetric theories with exact BPS domain wall solutions into supergravity, by introducing a gravitationally deformed superpotential. The gravitational deformation is natural in the spirit of maintaining the Kähler inv

David Orden, Francisco Santos, Brigitte Servatius, Herman Servatius

We prove that a planar graph is generically rigid in the plane if and only if it can be embedded as a pseudo-triangulation. This generalizes the main result of math.CO/0307347 which treats the minimally generically rigid case. The proof uses the concept of combinatorial pseudo-triangulation, CPT, in the plane and has two main steps: showing that a certain ``

S. J. van Enk

We describe the resonant interaction of an atom with a strongly focused light beam by expanding the field in multipole waves. For a classical field, or when the field is described by a coherent state, we find that both intensity pattern and photon statistics of the scattered light are fully determined by a small set of parameters. One crucial parameter is th

Zai-Zhe Zhong

By using of a special reduction way of density matrices, in this Letter we find the entanglement between two bunches of particles, its measure can be represented by the entanglement of formation.

M. F. Andersen, A. Kaplan, T. Grünzweig, N. Davidson

Ultra-cold atoms trapped in an optical dipole trap and prepared in a coherent superposition of their hyperfine ground states, decohere as they interact with their environment. We demonstrate than the loss in coherence in an "echo" experiment, which is caused by mechanisms such as Rayleigh scattering, can be suppressed by the use of a new pulse sequen

S. P. Walborn, S. Pádua, C. H. Monken

We propose a simple scheme for complete Bell-state measurement of photons using hyperentangled states - entangled in multiple degrees of freedom. In addition to hyperentanglement, our scheme requires only linear optics and single photon detectors, and is realizable with current technology. At the cost of additional classical communication, our Bell-state mea

F. Schmidt-Kaler, H. Haeffner, S. Gulde, M. Riebe

A single 40Ca+ ion is trapped and laser cooled to its motional ground state. Laser radiation which couples off-resonantly to a motional sideband of the ion's S1/2 to D5/2 transition causes a phase shift proportional to the ion's motional quantum state |n>. As the phase shift is conditional upon the ion's motion, we are able to demonstrate a unive

C. F. Roos, G. P. T. Lancaster, M. Riebe, H. Haeffner

We report on tomographic means to study the stability of a qubit register based on a string of trapped ions. In our experiment, two ions are held in a linear Paul trap and are entangled deterministically by laser pulses that couple their electronic and motional states. We reconstruct the density matrix using single qubit rotations and subsequent measurements

E. Paspalakis, Z. Kis

We consider a method for efficient parametric generation of a laser pulse. A single laser field is injected to a three-level medium which has two lower states and one excited state. The lower states are prepared initially in a position-dependent coherent superposition state. It is shown that by proper choice of the position dependence of the superposition al

Z. Kis, F. Renzoni

We introduce a novel procedure for qubit rotation, alternative to the commonly used method of Rabi oscillations of controlled pulse area. It is based on the technique of Stimulated Raman Adiabatic Passage (STIRAP) and therefore it is robust against fluctuations of experimental parameters. Furthermore, our work shows that it is in principle possible to perfor

Asoka Biswas, G. S. Agarwal

Strong subadditivity inequality for a three-particle composite system is an important inequality in quantum information theory which can be studied via a four-particle entangled state. We use two three-level atoms in $Λ$ configuration interacting with a two-mode cavity and the Raman adiabatic passage technique for the production of the four-particle entangle

Morton H. Rubin

We discuss the problem of when a set of measurements made on an entangled source can be simulated with a classically correlated source. This is discussed in general and some examples are given. The question of which aspects of quantum imaging can be simulated by classically correlated sources is examined.

Christopher A. Fuchs, Masahide Sasaki

In this paper we propose a general method to quantify how "quantum" a set of quantum states is. The idea is to gauge the quantumness of the set by the worst-case difficulty of transmitting the states through a purely classical communication channel. Potential applications of this notion arise in quantum cryptography, where one might like to use an al

Howard Barnum, Patrick Hayden, Richard Jozsa, Andreas Winter

Consider a source E of pure quantum states with von Neumann entropy S. By the quantum source coding theorem, arbitrarily long strings of signals may be encoded asymptotically into S qubits/signal (the Schumacher limit) in such a way that entire strings may be recovered with arbitrarily high fidelity. Suppose that classical storage is free while quantum stora

Dario G. Perez

First, we make a revision of the up-to-date Passive Scalar Fields properties: also, the refractive index is among them. Afterwards, we formulated the properties that make the family of `isotropic' fractional Brownian motion (with parameter H) a good candidate to simulate the turbulent refractive index. Moreover, we obtained its fractal dimension which ma

M. J. Olascoaga, F. J. Beron-Vera, J. Sheinbaum

In this paper we extend earlier results regarding the effects of the lower layer of the ocean (below the thermocline) on the baroclinic instability within the upper layer (above the thermocline). We confront quasigeostrophic baroclinic instability properties of a 2.5-layer model with those of a 3-layer model with a very thick deep layer, which has been shown

F. J. Beron-Vera

Salmon's nearly geostrophic model for rotating shallow-water flow is derived in full spherical geometry. The model, which results upon constraining the velocity field to the height field in Hamilton's principle for rotating shallow-water dynamics, constitutes an important prototype of Hamiltonian balanced models. Instead of Salmon's original appr

M. A. C. Potenza, S. Minardi, J. Trull, G. Blasi

We exploit a slightly noncollinear second-harmonic cross-correlation scheme to map the 3D space-time intensity distribution of an unknown complex-shaped ultrashort optical pulse. We show the capability of the technique to reconstruct both the amplitude and the phase of the field through the coherence of the nonlinear interaction down to a resolution of 10 $μ

Pier Paolo Delsanto, Caterina Guiot, Piero Giorgio Degiorgis, Carlos A. Condat

Most organisms grow according to simple laws, which in principle can be derived from energy conservation and scaling arguments, critically dependent on the relation between the metabolic rate B of energy flow and the organism mass m. Although this relation is generally recognized to be of the form B(m) = mp, the specific value of the exponent p is the object

Agnes Helmstetter, Didier Sornette

Mega et al.(cond-mat/0212529) proposed to use the ``diffusion entropy'' (DE) method to demonstrate that the distribution of time intervals between a large earthquake (the mainshock of a given seismic sequence) and the next one does not obey Poisson statistics. We have performed synthetic tests which show that the DE is unable to detect correlations b

Rudolph C. Hwa, C. B. Yang

The phenomenon of centrality scaling in the high-\pt spectra of $π^0$ produced in Au-Au collisions at $\sqrt s=200$ GeV is examined in the framework of relating fractional energy loss to fractional centrality increase. A new scaling behavior is found where the scaling variable is given a power-law dependence on $N_{\rm part}$. The exponent $γ$ specifies the

R. J. Furnstahl

The current generation of covariant mean-field models has had many successes in calculations of bulk observables for medium to heavy nuclei, but there remain many open questions. New challenges are confronted when trying to systematically extend these models to reliably address nuclear structure physics away from the line of stability. In this lecture, we di

M. Guttormsen, R. Chankova, M. Hjorth-Jensen, J. Rekstad

Experimental level densities for 171,172Yb, 166,167Er, 161,162Dy, and 148,149Sm are analyzed within the microcanonical ensemble. In the even isotopes at excitation energies E < 2 MeV, the Helmholtz free energy F signals the transition from zero to two quasiparticles. For E > 2 MeV, the odd and even isotopes reveal a surprisingly constant F at a critical temp

Yuriy Hlushchuk, Stefanie Russ

We study the level statistics (second half moment $I_0$ and rigidity $Δ_3$) and the eigenfunctions of pseudointegrable systems with rough boundaries of different genus numbers $g$. We find that the levels form energy intervals with a characteristic behavior of the level statistics and the eigenfunctions in each interval. At low enough energies, the boundary

Dragomir Neshev, Andrey A. Sukhorukov, Yuri S. Kivshar, Wieslaw Krolikowski

We study experimentally the Bloch-wave instabilities in optically-induced lattices. We reveal two different instability scenarios associated with either the transverse modulational instability of a single Bloch wave, or the nonlinear inter-band coupling between different Bloch waves. These effects are compared with the transverse instability in homogeneous m

N. P. Landsman

We propose that geometric quantization of symplectic manifolds is the arrow part of a functor, whose object part is deformation quantization of Poisson manifolds. The `quantization commutes with reduction&#39; conjecture of Guillemin and Sternberg then becomes a special case of the functoriality of quantization. In fact, our formulation yields almost unlimit

Kapil Hari Paranjape

This is a paper based on a talk given at the Warwick Symposium on Algebraic Geometry in 1996. The resolution of singularities given by F. Bogomolov and A. Pantev (arXiv:math.AG/9603019) is presented in a self-contained and &#34;elementary&#34; manner. The main result is that given a variety and a proper closed subvariety, there is a projective birational mor

Xianghong Gong

We show that for $n \geq 2$ there exist real analytic Hamiltonian systems on $\mathbf{R}^{2n}$ with non-resonant eigenvalues at a singular point, of which the Birkhoff normal form itself is divergent. The proof of the result is achieved by analyzing how the small-divisors enter the normal form.

Marta Casanellas, Elena Drozd, Robin Hartshorne

We study Gorenstein liaison of codimension two subschemes of an arithmetically Gorenstein scheme X. Our main result is a criterion for two such subschemes to be in the same Gorenstein liaison class, in terms of the category of ACM sheaves on X. As a consequence we obtain a criterion for X to have the property that every codimension 2 arithmetically Cohen-Mac

M. L. Barberis, I. Dotti

We study existence of complex structures on semidirect products $\g \oplus_ρ \v$ where $\g$ is a real Lie algebra and $ρ$ is a representation of $\g$ on $\v$. Our first examples, the Euclidean algebra $\e(3)$ and the Poincaré algebra $ \e(2,1)$, carry complex structures obtained by deformation of a regular complex structure on $\sl (2, \c)$. We also exhibit

Kiyonori Gomi

On the basis of Brylinski&#39;s work, we introduce a notion of equivariant smooth Deligne cohomology group, which is a generalization of both the ordinary smooth Deligne cohomology and the ordinary equivariant cohomology. Using the cohomology group, we classify equivariant circle bundles with connection, and equivariant gerbes with connection.

Timoteo Carletti, Gabriele Villari

We consider the Liénard equation and we give a sufficient condition to ensure existence and uniqueness of limit cycles. We compare our result with some other existing ones and we give some applications.

Yoshinori Namikawa

This paper is a sequel to math.AG/0203287. A generalization of the Mukai flop has been studied by E. Markman. Here we call it a stratified Mukai flop. In this paper, we observe that, for a stratified Mukai flop: $X \to \bar{X} \leftarrow X^+$, the fiber product $X \times_{\bar{X}}X^+$ defines an isomorphism of Grothendieck groups $K(X) \to K(X^+)$, but, at t

Vishvajit V. S. Gautam

In this article we give application of closure operators in category of modules. Our main result shows that every subcategory A of injective modules of R-mod (under a mild condition) induces a torsion theory of R-mod.

Pavol Severa

There is a simple and natural quantization of differential forms on odd Poisson supermanifolds, given by the relation [f,dg]={f,g} for any two functions f and g. We notice that this non-commutative differential algebra has a geometrical realization as a convolution algebra of the symplectic groupoid integrating the Poisson manifold. This quantization is just

Tomek Bartoszynski, Masaru Kada

We prove the following theorem: For a partially ordered set Q such that every countable subset has a strict upper bound, there is a forcing notion satisfying ccc such that, in the forcing model, there is a basis of the meager ideal of the real line which is order-isomorphic to Q with respect to set-inclusion. This is a variation of Hechler&#39;s classical re

Matthias Kuenzer, Gabriele Nebe

The elementary divisors of the Gram matrices of Specht modules S^lambda over the symmetric group are determined for two-row partitions and for two-column partitions lambda. More precisely, the subquotients of the Jantzen filtration are calculated using Schaper&#39;s formula. Moreover, considering a general partition lambda of n at a prime p > n - lambda_1, t

Tom Braden

For a normal variety X defined over an algebraically closed field with an action of the multiplicative group G_m, we consider the ``hyperbolic localization&#39;&#39; functor from D^b(X) to D^b(X^T), which localizes using closed supports in the directions flowing into the fixed points, and compact supports in the directions flowing out. We show that the hyper

Suhyoung Choi

An orbifold is a topological space modeled on quotient spaces of a finite group actions. We can define the universal cover of an orbifold and the fundamental group as the deck transformation group. Let $G$ be a Lie group acting on a space $X$. We show that the space of isotopy-equivalence classes of $(G,X)$-structures on a compact orbifold $Σ$ is locally hom

T. S. Nyawelo

We work out some properties of a recently proposed globally N = 1 supersymmetric extension of relativistic fluid mechanics in four-dimensional Minkowski space. We construct the lagrangean, discuss its symmetries and the corresponding conserved Noether charges. We reformulate the theory in hamiltonian formulation, and rederive the (supersymmetry and internal)

Takashi Tamaki, Sugumi Kanno, Jiro Soda

Non-uniform black strings in the two-brane system are investigated using the effective action approach. It is shown that the radion acts as a non-trivial hair of the black strings. From the brane point of view, the black string appears as the deformed dilatonic black hole which becomes dilatonic black hole in the single brane limit and reduces to the Reissne

Ya. Shnir

The problem of construction of fiber bundle over the moduli space of the Skyrme model is considered. We analyse an extension of the original Skyrme model which includes the minimal interaction with fermions. An analogy with modili space of the fermion-monopole system is used to construct a fiber bundle structure over the skyrmion moduli space. The possibilit

S. Nussinov

We point out that existing $K^+d$ scattering data available in the PDG (Particle Data Group compilation) suggest some fluctuations in those momentum bins where the (Fermi motion broadened) $Θ^+$[1543] resonance recently indicated in many gamma nuclear reactions and predicted six years ago by Diakonv Petrov and Polyakov might have shown up. The I=0, $J^P={1/2

Yudi Santoso

I review a generalization of CMSSM/mSUGRA model in which the Higgs masses are let to be free, namely the Non Universal Higgs Masses (NUHM) model. In our study we explore this model by employing constraints from cosmology as well as from particle physics to restrict the parameter space. We also calculate the neutralino-proton cross section in the allowed regi

S. Juchem, W. Cassing, C. Greiner

The quantum time evolution of ϕ^4-field theory for a spatially homogeneous system in 2+1 space-time dimensions is investigated numerically for out-of-equilibrium initial conditions on the basis of the Kadanoff-Baym equations including the tadpole and sunset self-energies. Whereas the tadpole self-energy yields a dynamical mass, the sunset self-energy is resp

Nikolaos Kidonakis, J. F. Owens

Previous work on soft-gluon resummation for direct photon production is extended to include additional subleading logarithmic terms through O(alpha alpha_s^3) and some representative comparisons are made to experimental results from the E-706 and UA-6 Collaborations. The additional terms are small in magnitude, indicating good convergence properties to the l

J. Orloff

We review the experimental evidence for a net baryon density in cosmology, and the theoretical mechanism for producing it, called leptogenesis, which relies on the creation of a lepton asymmetry at an intermediate step. The naturality of this mechanism and its possible relations with neutrino oscillations are outlined.

Uma Mahanta, Sreerup Raychaudhuri

We constrain the parameters of dynamical torsion, namely, the torsion-fermion coupling and the torsion mass, by making a careful analysis of current LEP-2 data at several energies, as well as CDF and D0 data from Run-I of the Tevatron. We find that measurements of the forward-backward asymmetry in the e+- e- -> mu+- mu- channel at LEP-2 produce the most rest

G. S. Huang

We present a preliminary measurement of the composition of inclusive semileptonic B meson decays using 9.4 fb^{-1} of e^+e^- data taken with the CLEO detector at the Upsilon(4S) resonance. In addition to measuring the charged lepton kinematics, the neutrino four-vector is inferred using the hermeticity of the detector. We perform a maximum likelihood fit ove

V. M. Abazov

A search for narrow resonances that decay into t-tbar pairs has been performed using 130 pb^{-1} of data in the lepton+jets channel collected in p-pbar collisions at \sqrt{s} = 1.8 TeV. There is no significant deviation observed from the standard model, and upper limits at the 95 % confidence level on the product of the production cross section and branching

M. Sharif

Matter collineations of spherically Symmetric Lorentzian Manifolds are considered. These are investigated when the energy-momentum tensor is non-degenerate and also when it is degenerate. We have classified spacetimes admitting higher symmetries and spacetimes admitting SO(3) as the maximal isometry group. For the non-degenerate case, we obtain either {\it f

Nobuyuki Sawado, Noriko Shiiki

It has been known that a B=2 skyrmion is axially symmetric. We consider the Skyrme model coupled to gravity and obtain static axially symmetric black hole solutions numerically. The black hole skyrmion no longer has integer baryonic charge but has fractional charge outside the horizon as in the spherically symmetric case. Therefore, the solution represents a

Saulo Carneiro

We study a uniform and isotropic cosmology with a decaying vacuum energy density, in the realm of a model with a time varying gravitational &#34;constant&#34;. We show that, for late times, such a cosmology is in accordance with the observed values of the cosmological parameters. In particular, we can obtain the observed ratio between the matter density and

Oleg Lodygensky, Gilles Fedak, Vincent Neri, Alain Cordier

In this paper, we present XtremWeb, a Global Computing platform used to generate monte carlos showers in Auger, an HEP experiment to study the highest energy cosmic rays at Mallargue-Mendoza, Argentina. XtremWeb main goal, as a Global Computing platform, is to compute distributed applications using idle time of widely interconnected machines. It is especiall

Stanimire Tomov, Robert Bennett, Michael McGuigan, Arnold Peskin

We present an efficient and inexpensive to develop application for interactive high-performance parallel visualization. We extend popular APIs such as Open Inventor and VTK to support commodity-based cluster visualization. Our implementation follows a standard master/slave concept: the general idea is to have a ``Master&#39;&#39; node, which will intercept a

Magnus Boman, Anna Sandin

An experimental server for stock trading autonomous agents is presented and made available, together with an agent shell for swift development. The server, written in Java, was implemented as proof-of-concept for an agent trade server for a real financial exchange.

J Gerard Wolff

This paper describes an approach to the representation and processing of ontologies in the Semantic Web, based on the ICMAUS theory of computation and AI. This approach has strengths that complement those of languages based on the Resource Description Framework (RDF) such as RDF Schema and DAML+OIL. The main benefits of the ICMAUS approach are simplicity and

Artur Sowa

This article is concerned with the existence, status and description of the so-called emergent phenomena believed to occur in certain principally planar electronic systems. In fact, two distinctly different if inseparable tasks are accomplished. First, a rigorous mathematical model is proposed of emergent character, which is conceptually bonded with Quantum

Hai Qian, Gene F. Mazenko

We introduce a model for describing the defected growth of striped patterns. This model, while roughly related to the Swift-Hohenberg model, generates a quite different mixture of defects during phase ordering. We find two characteristic lengths in the system: the scaling length L(t), and the average width of the domain walls. The growth law exponent is larg

A. J. R. da Silva, A. Fazzio, R. R. dos Santos, L. E. Oliveira

We have performed ab initio calculations within the density-functional theory for Ga_{1-x}Mn_xAs diluted semiconductors. Total energy results unambiguously show that a quasi-localized down-spin hole, with strong p-like character, surrounds the fully polarized Mn up-spin d^5-electrons. Calculations indicate that the holes form an essentially dispersionless im

N. P. Armitage, J. -C. P. Gabriel, G. Gruner

The handling and manipulation of carbon nanotubes continues to be a challenge to those interested in the application potential of these promising materials. To this end, we have developed a method to deposit pure nanotube films over large flat areas on substrates of arbitrary composition. The method bears some resemblance to the Langmuir-Blodgett deposition

Michelle Chen, Woowon Kang, Werner Wegscheider

We report on the dramatic evolution of the quantum Hall ferromagnet in the fractional quantum Hall regime at $ν= 2/5$ filling. A large enhancement in the characteristic timescale gives rise to a dynamical transition into a novel quantized Hall state. The observed Hall state is determined to be a zero-temperature phase distinct from the spin-polarized and spi

Oded Farago, Philip Pincus

We study the elastic properties of a two-dimensional fluctuating surface whose area density is allowed to deviate from its optimal (Schulman) value. The behavior of such a surface is determined by an interplay between the area-dependent elastic energy, the curvature elasticity, and the entropy. We identify three different elastic regimes depending on the rat

Veronique Le Floc&#39;h, Sophie Brasselet, Jean-Francois Roch, Joseph Zyss

We present high resolution two-photon excitation microscopy studies combining two-photon fluorescence (TPF) and second harmonic generation (SHG) in order to probe orientational distributions of molecular ensembles at room temperature. A detailed polarization analysis of TPF and SHG signals is used in order to unravel the parameters of the molecular orientati

Kyungwha Park, Mark R. Pederson, C. Stephen Hellberg

Most experimental data on the single-molecule magnet Mn$_{12}$ acetate have been successfully explained by the assumption that the Mn$_{12}$ acetate has an effective ground-state spin of S=10. However, the effect of the low-lying excited manifolds caused by interactions between Mn spins has not been well understood. To investigate the features of the low-lyi

E. del Barco, A. D. Kent, N. E. Chakov, L. N. Zakharov

A distribution of internal transverse magnetic fields has been observed in single molecule magnet (SMM) Mn12-BrAc in the pure magnetic quantum tunneling (MQT) regime. Magnetic relaxation experiments at 0.4 K are used to produce a hole in the distribution of transverse fields whose angle and depth depend on the orientation and amplitude of an applied transver

M. V. Fistul, A. Wallraff, Y. Koval, A. Lukashenko

We report a theoretical analysis and experimental observation of the quantum dynamics of a single vortex-antivortex (VAV) pair confined in a long narrow annular Josephson junction. The switching of the junction from the superconducting state to the resistive state occurs via the dissociation of a pinned VAV pair. The pinning potential is controlled by extern

Jonathan L. Bentz, John J. Kozak, E. Abad, G. Nicolis

The role of dimensionality (Euclidean versus fractal), spatial extent, boundary effects and system topology on the efficiency of diffusion-reaction processes involving two simultaneously-diffusing reactants is analyzed. We present numerically-exact values for the mean time to reaction, as gauged by the mean walklength before reactive encounter, obtained via

Enrique Canessa

A general statistical thermodynamic theory that considers given sequences of x-integers to play the role of particles of known type in an isolated elastic system is proposed. By also considering some explicit discrete probability distributions p_{x} for natural numbers, we claim that they lead to a better understanding of probabilistic laws associated with n

Y. M. Meziani, C. Chaubet, B. Jouault, S. Bonifacie

Our study presents experimental measurements of the contact and longitudinal voltage drops in Hall bars, as a function of the current amplitude. We are interested in the heating phenomenon which takes place before the breakdown of the quantum Hall effect, i.e. the pre-breakdown regime. Two types of samples has been investigated, at low temperature (4.2 and 1

V. Bellini, F. Manghi, T. Thonhauser, C. Ambrosch-Draxl

We present detailed first-principles calculations for the normal state electronic properties of the high T$_C$ superconductor Bi$_2$Sr$_2$CaCu$_2$O$_8$, by means of the linearized augmented plane wave (LAPW) method within the framework of density functional theory (DFT). As a first step, the body centered tetragonal (BCT) cell has been adopted, and optimized

F. Giazotto, F. Taddei, T. T. Heikkila, R. Fazio

A superconductor-normal metal-superconductor (SNS) transistor based on superconducting microcoolers is presented. The proposed 4-terminal device consists of a long SNS Josephson junction whose N region is in addition symmetrically connected to superconducting reservoirs through tunnel barriers (I). Biasing the SINIS line allows to modify the quasiparticle te

Nicola Manini, Paolo Gattari, Erio Tosatti

The h_u hole spectral intensity for C60 -> C60+ molecular photoemission is calculated at finite temperature by a parameter-free Lanczos diagonalization of the electron-vibration Hamiltonian, including the full 8 H_g, 6 G_g, and 2 A_g mode couplings. The computed spectrum at 800 K is in striking agreement with gas-phase data. The energy separation of the firs

I. Shlimak, V. Ginodman, M. Levin, M. Potemski

We have investigated temperature dependence of the longitudinal conductivity $σ_{xx}$ at integer filling factors $ν=i$ for Si/SiGe heterostructure in the quantum Hall effect regime. It is shown that for odd $i$, when the Fermi level $E_{F}$ is situated between the valley-split levels, $Δσ_{xx}$ is determined by quantum corrections to conductivity caused by t

Paul Tangney, Sandro Scandolo

An analytic representation of the short-range repulsion energy in ionic systems is described that allows for the fact that ions may change their size and shape depending on their environment. This function is extremely efficient to evaluate relative to previous methods of modeling the same physical effects. Using a well-defined parametrization procedure we h

G. T. Woods, R. J. Soulen, I. I. Mazin., B. Nadgorny

We present a systematic analysis of point-contact Andreev reflection (PCAR) spectra for ferromagnetic materials, using both modeling and experimental data. We consider the relationship between ballistic and diffusive transport, the effect of different transport regimes on spin polarization measurements, and the importance of unambiguous identification of the

Baowen Li, Giulio Casati, Jiao Wang, Tomaz Prosen

We study energy transport in a one-dimensional model of elastically colliding particles with alternate masses $m$ and $M$. In order to prevent total momentum conservation we confine particles with mass $M$ inside a cell of finite size. We provide convincing numerical evidence for the validity of Fourier law of heat conduction in spite of the lack of exponent

Zhao-hua Cheng, Zhi-hong Wang, Nai-li Di, Zhi-qi Kou

Local structure of the Fe-doped La$_{1-x}$Ca$_{x}$MnO$_{3}$ (x=0.00-1.00) compounds has been investigated by means of Mössbauer spectroscopy. $^{57}$Fe Mössbauer spectra provide a direct evidence of Jahn-Teller distortion in these manganites. On the basis of Mössbauer results, the Jahn-Teller coupling was estimated. It is noteworthy that Ca-concentration dep

Julian Lee, In-Ho Lee, Jooyoung Lee

We apply the conformational space annealing (CSA) method to the Lennard-Jones clusters and find all known lowest energy configurations up to 201 atoms, without using extra information of the problem such as the structures of the known global energy minima. In addition, the robustness of the algorithm with respect to the randomness of initial conditions of th

R. Baptista, B. W. Borges, H. E. Bond, F. Jablonski

We report the identification of cyclical changes in the orbital period of the eclipsing dwarf novae V2051 Ophiuchi and V4140 Sagitarii. We used sets of white dwarf mid-eclipse timings to construct observed-minus-calculated diagrams covering, respectively, 25 and 16 years of observations. The V2051 Oph data present cyclical variations that can be fitted by a

Y. Gomez, L. F. Rodriguez, J. M. Girart, G. Garay

We present high angular resolution VLA and BIMA observations of NH$_3$, HCO$^+$, HCN and SO molecular emission and 1.4, 3.5 and 7 mm continuum emission toward the exciting source of the HH~80-81 system. This object is one of the few massive protostars known to be driving a collimated outflow. We report the first detection of SO 5$_5$--4$_4$ molecular emissio

Alicia Porras, Micol Christopher, Lori Allen, James Di Francesco

We present a catalog of near-infrared surveys of young (<= a few 10^6 yr) stellar groups and clusters within 1 kpc from the Sun, based on an extensive search of the literature from the past ten years. We find 143 surveys from 69 published articles, covering 73 different regions. The number distribution of stars in a region has a median of 28 and a mean of 10

M. E. Putman, J. Bland-Hawthorn, S. Veilleux, B. K. Gibson

We present deep Halpha spectroscopy towards several high-velocity clouds (HVCs) which vary in structure from compact (CHVCs) to the Magellanic Stream. The clouds range from being bright (~640 mR) to having upper limits on the order of 30 to 70 mR. The Halpha measurements are discussed in relation to their HI properties and distance constraints are given to e

J. C. Ling, Wm. A. Wheaton

We report ~ 600 days of BATSE earth-occultation observations of the total gamma-ray (30 keV to 1.7 MeV) emission from the Crab nebula, between 1991 May 24 (TJD 8400) and 1994 October 2 (TJD 9627). Lightcurves from 35-100, 100-200, 200-300, 300-400, 400-700, and 700-1000 keV, show that positive fluxes were detected by BATSE in each of these six energy bands a

M. Still, G. A. J. Hussain

We report on ASCA observations of the coronally active companion star in the post-common envelope binary V471 Tauri. Evolutionary calculations indicate that there should be no peculiar abundances on the companion star resulting from the common envelope epoch. Indeed, we find no evidence for peculiar abundances, although uncertainties are high. We find that a

Aaron J. Grocholski, Ata Sarajedini

We present combined optical/near-IR photometry (BVIK) for six open clusters - M35, M37, NGC 1817, NGC 2477, NGC 2420, and M67. The open clusters span an age range from 150 Myr to 4 Gyr and have metal abundances from [Fe/H] = -0.3 to +0.09 dex. We have utilized these data to test the robustness of theoretical main sequences constructed by several groups as de

C. J. Cyganowski, M. J. Reid, V. L. Fish, P. T. P. Ho

The DR 21 massive star forming region contains two cometary HII regions, aligned nearly perpendicular to each other on the sky. This offers a unique opportunity to discriminate among models of cometary HII regions. We present hydrogen recombination and ammonia line observations of DR 21 made with the Very Large Array. The velocity of the molecular gas, measu

L. O. Silva, R. A. Fonseca, J. Tonge, J. M. Dawson

We present the first three-dimensional fully kinetic electromagnetic relativistic particle-in-cell simulations of the collision of two interpenetrating plasma shells. The highly accurate plasma-kinetic &#34;particle-in-cell&#34; (with the total of $10^8$ particles) parallel code OSIRIS has been used. Our simulations show: (i) the generation of long-lived nea

Stefano Gabici

The nonthermal radiation observed from a handfull of clusters of galaxies (CG) is the proof that particle acceleration occurs in the intracluster medium (ICM). It is often believed that shock surfaces associated with either mergers of CG, or with the cosmological inflow of matter onto clusters during structure formation may be the sites for acceleration. We

Michael Kappes, Juergen Kerp, Fabian Walter

We present an XMM-Newton observation of the nearby dwarf galaxy IC 2574. This galaxy is part of our ensemble observed within a multi-frequency campaign to study the physical conditions of the interstellar medium in dwarf galaxies in general. Here, we focus on the diffuse soft (0.2 - 0.5 keV) X-ray emission associated with IC 2574. Since this emission is expe

A. Olech, P. Kedzierski, K. Zloczewski, K. Mularczyk

We report extensive photometry of the dwarf nova QW Ser throughout its 2003 February superoutburst till quiescence. During the superoutburst the star displayed clear superhumps with a mean period of Psh = 0.07703(4) days. In the quiescence we observed a double humped wave characterized by a period of P=0.07457(2) days. As both periods obey the Stolz-Schoembs

A. Koch, M. Odenkirchen, E. K. Grebel, D. Martinez-Delgado

We present the main sequence luminosity function of the tidally disrupted globular cluster Palomar 5 and its tidal tails. For this work we analyzed imaging data obtained with the Wide Field Camera at the INT (La Palma) and data from the Wide Field Imager at the MPG/ESO 2.2 m telescope at La Silla down to a limiting magnitude of approximately 24.5 mag in B. O

Rene&#39; Liseau

The presence of gas in dusty debris disks around main-sequence stars is reviewed. We present new observational results for the most prominent representative of the class, viz. the southern naked-eye star beta Pictoris. The spatial and spectral distribution of observed atomic lines from the disk around the star is reproducable by a Keplerian rotation model to

T. Temma, N. J. Chanover, A. A. Simon-Miller, D. A. Glenar

Saturn was observed on 6-11 February 2002 using an Acousto-optic Imaging Spectrometer (AImS) to study Saturn&#39;s vertical cloud structure. The 3.67-m Advanced Electro-Optical System telescope at the Maui Space Surveillance Complex was used. The high spectral resolution and wide spectral coverage of AImS (500 - 1000 nm) enabled us to sample the Saturnian at

F. De Paolis, G. Ingrosso, A. Geralico, A. A. Nucita

Holz & Wheeler (\cite{hw}) have recently proposed that a Schwarzschild black hole may act as a retro-lens which, if illuminated by a powerful light source, deflects light ray paths to large bending angles and a series of luminous arcs (or rings in the case of aligned objects) centered on the black hole may form. Obviously, the most convenient geometry to get