March 2001 arXiv papers — page 21

K. W. Yu, Jones T. K. Wan

We have developed a Green's function formalism to compute the local field distribution near an interface separating two media of different dielectric constants. The Maxwell's equations are converted into a surface integral equation; thus it greatly simplifies the solutions and yields accurate results for interfaces of arbitrary shape. The integral eq

C. Panagopoulos, B. D. Rainford, J. R. Cooper, C. A. Scott

We study the doping dependence of low frequency spin fluctuations and the zero-temperature superfluid density of La$_{2-x}$Sr$_x$CuO$_4$ using the muon spin relaxation ($μ$SR) and ac-susceptibility techniques. Superconductivity is found to coexist with low frequency spin fluctuations over a large region of the superconducting phase diagram. The characteristi

Leticia Carigi

Two sets of observational carbon stellar yields for low-and-intermediate mass stars are computed from planetary nebulae abundances derived from C II $\lambda4267$ and C III $λ\lambda1906+1909$ lines, respectively. By comparing C/O values observed in stars of the solar vicinity and Galactic HII regions with those predicted by chemical evolution models for the

Ken D. Olum, J. J. Blanco-Pillado

It is difficult for conventional sources to accelerate cosmic ray particles to the highest energies that have been observed. Topological defects such as monopoles and strings overcome this difficulty, because their natural energy scale is at or above the observed energies. Monopoles connected by strings are a particularly attractive source, because they woul

David C. Knauth, S. R. Federman, K. Pan, M. Yan

High resolution optical spectra of HD 37903 and HD 147009, which illuminate the reflection nebulae, NGC 2023 and vdB 102, were obtained for comparison with our results for HD 200775 and NGC 7023. Ground-based measurements of the molecules, CH, C$_2$, and CN, and the atoms, Na I and K I, were analyzed to extract physical conditions in the foreground cloud. Es

A. Bressan, G. L. Granato, L. Silva

We examine the tight correlation observed between the far infrared (FIR) and radio emission in normal and star burst galaxies. We show that significant deviations from the average relation are to be expected in young star burst or post star burst galaxies, due to the different fading times of FIR and Radio power.

Wesley N. Colley, Rudolph E. Schild, Cristina Abajas, David Alcalde

An observing campaign with 10 participating observatories has undertaken to monitor the optical brightness of the Q0957 gravitationally lensed quasar for 10 consecutive nights in January 2000. The resulting A image brightness curve has significant brightness fluctuations and makes a photometric prediction for the B image light curve for a second campaign pla

Riccardo Scarpa, C. Megan Urry

The possibility of radio galaxies being random sample of otherwise normal elliptical galaxies is tested. Starting with the observed optical luminosity functions for elliptical galaxies, it is shown that the probability of an elliptical forming a radio source is a continuous, increasing function of optical luminosity, precisely proportional to square of the o

Felix Linke, Jose A. Font, Hans-Thomas Janka, E. Mueller

We present the results of numerical simulations of the spherically symmetric gravitational collapse of supermassive stars (SMS). The collapse is studied using a general relativistic hydrodynamics code. The coupled system of Einstein and fluid equations is solved employing observer time coordinates, by foliating the spacetime by means of outgoing null hypersu

J. A. Peacock, S. Cole, P. Norberg, C. M. Baugh

The large-scale structure in the distribution of galaxies is thought to arise from the gravitational instability of small fluctuations in the initial density field of the universe. A key test of this hypothesis is that superclusters of galaxies in the process of formation should generate systematic infall of other galaxies. This would be evident in the patte

Charles H. Lineweaver

I attempt to piece together a consistent scenario based on current estimates of the evolution of the star formation rate of the Universe, the metallicity evolution of the star-forming regions of the Universe and the most recent observations of extrasolar planets. The precision of all of these data sets is improving rapidly, but they can already be combined t

G. R. Knapp, D. Pourbaix, A. Jorissen

The Hipparcos Intermediate Astrometric Data for carbon stars have been reprocessed using an algorithm which provides an objective criterion for rejecting anomalous data points and constrains the parallax to be positive. New parallax solutions have been derived for 317 cool carbon stars, mostly of types R and N. In this paper we discuss the results for the R

Mallory S. E. Roberts, Peter F. Michelson, Denis A. Leahy, Tony A. Hall

We report on ASCA, RXTE, and archival observations of the high mass X-ray binary pulsar 4U1907+09. Spectral measurements of the absorption and flux were made at all phases of the X-ray pulsar orbit, including the first spectral measurements of an extended period of low flux during two of the ASCA observations. We find that a simple spherical wind model can f

Krzysztof Roszkowski

This note tackles the problem of the backscattering of a mass-less scalar field in the case of Schwarzschildean space-time. It shows that the effect depends both on a distance from the horizon and on the wave length. The obtained estimates significantly improve former results.

Hyung Cho, Gary A. Williams

A normal-fluid component varying as T$^{2}$ is observed at very low temperatures in superfluid $^4$He and $^3$He-$^4$He mixture films adsorbed in alumina powder. The normal fluid appears to arise from thermally excited third sound that has one-dimensional propagation characteristics. A Landau model of third sound excitations in an infinite cylindrical pore b

C. A. de S. Pires, P. S. Rodrigues da Silva

In this work we address contributions from scalars to (g-2)_μ. In order to explain the recently measured deviation by the BNL experiment on (g-2)_μ, it is necessary that these scalars are either light or couple strongly with muons. Here we explore this last possibility. We show that a scalar with mass of the order of 10^2 GeV provides significant contributio

L. -A. Wu, D. A. Lidar

We study the quantum computational power of a generic class of anisotropic solid state Hamiltonians. A universal set of encoded logic operations are found which do away with difficult-to-implement single-qubit gates in a number of quantum computer proposals, e.g., quantum dots and donor atom spins with anisotropic exchange coupling, quantum Hall systems, and

Erik Helgren, George Grüner, Martin Ciofalo, David V. Baxter

We have conducted temperature and frequency dependent transport measurements in amorphous Nb_x Si_{1-x} samples in the insulating regime. We find a temperature dependent dc conductivity consistent with variable range hopping in a Coulomb glass. The frequency dependent response in the millimeter-wave frequency range can be described by the expression $sigma(o

Gordon Chalmers

The amplitudes in perturbative open string theory are examined as functions of the tachyon condensate parameter. The boundary state formalism demonstrates the decoupling of the open string modes at the non-perturbative minima of the tachyon potential via a degeneration of open world-sheets and identifies an independence of the coupling constants $g_s$ and $g

S. Bettelli, L. Serafini, T. Calarco

It is becoming increasingly clear that, if a useful device for quantum computation will ever be built, it will be embodied by a classical computing machine with control over a truly quantum subsystem, this apparatus performing a mixture of classical and quantum computation. This paper investigates a possible approach to the problem of programming such machin

M. Leone, F. Ricci-Tersenghi, R. Zecchina

We study an exactly solvable version of the famous random Boolean satisfiability problem, the so called random XOR-SAT problem. Rare events are shown to affect the combinatorial ``phase diagram'' leading to a coexistence of solvable and unsolvable instances of the combinatorial problem in a certain region of the parameters characterizing the model. S

Stephen L. Adler, Todd A. Brun

A number of authors have proposed stochastic versions of the Schrödinger equation, either as effective evolution equations for open quantum systems or as alternative theories with an intrinsic collapse mechanism. We discuss here two directions for generalization of these equations. First, we study a general class of norm preserving stochastic evolution equat

Nobuo Furukawa

As a model for the B 2pz bands of MgB$_2$, a half-filled Hubbard model on a honeycomb lattice is studied, and a possibility of an antiferromagnetism (AF) at the ground state is examined by Monte Carlo calculations as well as a random phase approximation method. On a single-layer honeycomb lattice, a paramagnetic to AF phase transition occurs at a finite valu

N. Rius, V. Sanz

We study dynamical electroweak symmetry breaking in the Randall-Sundrum scenario. We show that one extra dimension is enough to give the correct pattern of electroweak symmetry breaking in a simple model with gauge bosons and the right-handed top quark in the bulk. The top quark mass is also in agreement with experiment. Furthermore, we propose an extended s

Robert J. Bursill

In a Physical Review B paper Chandross and Hicks claim that an analysis of the density-density correlation function in the dimerised Hubbard model of polyacetylene indicates that the optical exciton is bound, and that a previous study by Boman and Bursill that concluded otherwise was incorrect due to numerical innacuracy. We show that the method used in our

T. Nakanishi, K. Yamane, M. Kitano

We show that atomic spin motion can be controlled by circularly polarized light without light absorption in the strong pumping limit. In this limit, the pumping light, which drives the empty spin state, destroys the Zeeman coherence effectively and freezes the coherent transition via the quantum Zeno effect. It is verified experimentally that the amount of l

Chongxing Yue, Qingjun Xu, Guoli Liu

We discuss and estimate the contributions of the new particles predicted by topcolor assisted technicolor(TC2) models to the muon anomalous magnetic moment $a_μ$. Our results show that the contributions of Pseudo Goldstone bosons are very small which can be safely ignored. The main contributions come from the ETC gauge boson $x_μ$ and topcolor gauge boson $Z

N. Harrison, C. H. Mielke, J. Singleton, J. Brooks

Resistivity and irreversible magnetisation data taken within the high-magnetic-field CDWx phase of the quasi-two-dimensional organic metal alpha-(BEDT-TTF)2KHg(SCN)4 are shown to be consistent with a field-induced inhomogeneous superconducting phase. In-plane skin-depth measurements show that the resistive transition on entering the CDWx phase is both isotro

Kun Hu, Plamen Ch. Ivanov, Zhi Chen, Pedro Carpena

Detrended fluctuation analysis (DFA) is a scaling analysis method used to estimate long-range power-law correlation exponents in noisy signals. Many noisy signals in real systems display trends, so that the scaling results obtained from the DFA method become difficult to analyze. We systematically study the effects of three types of trends -- linear, periodi

Rudy Wijnands

Two flares with a duration of several hours are reported for the low-mass X-ray binary 4U 1636-53. The characteristics of these flares (i.e., decay time scales, spectral softening, fluences) are very similar to the very long type-I X-ray bursts recently found in several other low-mass X-ray binaries, suggesting that the flares in 4U 1636-53 are also very lon

Jay Gambetta, H. M. Wiseman

Following the evolution of an open quantum system requires full knowledge of its dynamics. In this paper we consider open quantum systems for which the Hamiltonian is ``uncertain''. In particular, we treat in detail a simple system similar to that considered by Mabuchi [Quant. Semiclass. Opt. 8, 1103 (1996)]: a radiatively damped atom driven by an un

Hans Halvorson, Rob Clifton

Several recent arguments purport to show that there can be no relativistic, quantum-mechanical theory of localizable particles and, thus, that relativity and quantum mechanics can be reconciled only in the context of quantum field theory. We point out some loopholes in the existing arguments, and we provide two no-go theorems to close these loopholes. Howeve

Arthur O. Pittenger, Morton H. Rubin

A finite dimensional quantum mechanical system is modeled by a density rho, a trace one, positive semi-definite matrix on a suitable tensor product space H[N] . For the system to demonstrate experimentally certain non-classical behavior, rho cannot be in S, a closed convex set of densities whose extreme points have a specificed tensor product form. Two mathe

Peter Rowlands, J. P. Cullerne

The nilpotent version of the Dirac equation is applied to the baryon wavefunction, the strong interaction potential, electroweak mixing, and Dirac and Klein-Gordon propagators. The results are used to interpret a quaternion-vector model of particle structures.

Milena D'Angelo, Maria V. Chekhova, Yanhua H. Shih

We report a proof-of-principle experimental demonstration of quantum lithography. Utilizing the entangled nature of a two-photon state, the experimental results have bettered the classical diffraction limit by a factor of two. This is a quantum mechanical two-photon phenomenon but not a violation of the uncertainty principle.

C. Skornia, J. von Zanthier, G. S. Agarwal, E. Werner

The emission characteristics in the fluorescence of two laser-driven dipole-dipole-interacting three level atoms is investigated. When the light from both atoms is detected separately a correlation of the emission processes is observed in dependence of the dipole-dipole interaction. This opens the possibility to investigate the dipole-dipole interaction thro

L. Canton, G. Pisent, W. Schadow, T. Melde

We report on recent results obtained by the above collaboration on the collision processes involving three nucleons, where we pay particular attention on the dynamical role of the pion. After discussing the case at intermediate energies, where real pions can be produced and detected, we have considered the case at lower energies, where the pions being exchan

Dinesh Kumar Srivastava

It has been shown recently shown that the values of $J_T$ and $J_L$ which appear in Eq.(2) and (5) of the above paper and which are taken from the work of Aurenche et al are too large by a factor of 4. Correcting for this changes the Fig.~1--4. The basic result of the paper, that the emissions from the quark matter can outshine those from the hadronic matter

Dinesh Kumar Srivastava, Bikash Chandra Sinha

It has been shown recently that the values of $J_T$ and $J_L$ which appear in Eqs.(2) and (5) of the above paper and which are taken from the work of Aurenche et al are too large by a factor of 4. Correcting for this changes the Fig.~2. More-over, now the emissions from the quark matter dominate only for $p_T <$ 1 GeV/$c$. The basic result of the paper, that

Christian Hainzl

This paper deals with the comparison between the strong Thomas-Fermi theory and the quantum mechanical ground state energy of a large atom confined to lowest Landau band wave functions. Using the tools of microlocal semiclassical spectral asymptotics we derive precise error estimates. The approach presented in this paper suggests the definition of a modified

Florin Panaite

If H is a finite dimensional Hopf algebra, C. Cibils and M. Rosso found an algebra X having the property that Hopf bimodules over H^* coincide with left X-modules. We find two other algebras, Y and Z, having the same property; namely, Y is the &#34;two-sided crossed product&#34; H^*#(H\otimes H^{op})# H^{* op} and Z is the &#34;diagonal crossed product&#34;

David Applegate, Jeffrey C. Lagarias

The 3X+1 function T(n) is (3n+1)/2 if n is odd and n/2 if n is even. The total stopping time σ_\infty (n) for a positive integer n is the number of iterations of the 3x+1 function to reach 1 starting from n, and is \infty if 1 is never reached. The 3x+1 conjecture states that this function is finite. We show that infinitely many n have a finite total stoppin

Carlos D&#39;Andrea

We prove a conjectured relationship among resultants and the determinants arising in the formulation of the method of moving surfaces for computing the implicit equation of rational surfaces formulated by Sederberg. In addition, we extend the validity of this method to the case of not properly parametrized surfaces without base points.

Roman Linares, Luis F. Urrutia, J. David Vergara

The exact solution of the Schwinger model with compact gauge group U(1) is presented. The compactification is imposed by demanding that the only surviving true electromagnetic degree of freedom has angular character. Not surprinsingly, this topological condition defines a version of the Schwinger model which is different from the standard one, where $c$ take

O. A. Castro-Alvaredo, A. Fring

We propose a renormalization group scaling function which is constructed from q-deformed fermionic versions of Virasoro characters. By comparison with alternative methods, which take their starting point in the massive theories, we demonstrate that these new functions contain qualitatively the same information. We show that these functions allow for RG-flows

Asim Gangopadhyaya, Jeffry V. Mallow, Uday P. Sukhatme

Although eigenspectra of one dimensional shape invariant potentials with unbroken supersymmetry are easily obtained, this procedure is not applicable when the parameters in these potentials correspond to broken supersymmetry, since there is no zero energy eigenstate. We describe a novel two-step shape invariance approach as well as a group theoretic potentia

H. Nikolic

If particle creation is described by a Bogoliubov transformation, then, in the Heisenberg picture, the raising and lowering operators are time dependent. On the other hand, this time dependence is not consistent with field equations and the conservation of the stress-energy tensor. Possible physical interpretations and resolutions of this inconsistency are d

G. Pinter

We show how the Hopf algebra structure of renormalization discovered by Kreimer can be found in the Epstein-Glaser framework without using an analogue of the forest formula of Zimmermann.

G. Colangelo, J. Gasser, H. Leutwyler

We demonstrate that, together with the available experimental information, chiral symmetry determines the low energy behaviour of the $ππ$ scattering amplitude to within very small uncertainties. In particular, the threshold parameters of the S-, P-, D- and F-waves are predicted, as well as the mass and width of the $ρ$ and of the broad bump in the S-wave. T

H. H. Asatryan, H. M. Asatrian, C. Greub, M. Walker

We calculate O(alpha_s) two-loop virtual corrections to the differential decay width dGamma(B --> X_s l^+ l^-)/ds, where s is the invariant mass squared of the lepton pair. We also include those contributions from gluon bremsstrahlung which are needed to cancel infrared and collinear singularities present in the virtual corrections. Our calculation is restri

Gabriel A. Gonzalez-Sprinberg, Arcadi Santamaria, Jorge Vidal

We obtain new bounds for the magnetic dipole moments of the tau lepton. These limits on the magnetic couplings of the tau to the electroweak gauge bosons (gamma, W, Z) are set in a model independent way using the most general effective Lagrangian with the SU(2)_L x U(1)_Y symmetry. Comparison with data from the most precise experiments at high energies shows

H. V. Klapdor-Kleingrothaus, B. Majorovits, L. Baudis, A. Dietz

The status of dark matter search in Heidelberg is reviewed. After one year of running the HDMS prototype experiment in the Gran Sasso Underground Laboratory, the inner crystal of the detector has been replaced with a HPGe crystal of enriched 73Ge. The results of the operation of the HDMS prototype detector are discussed. In the light of the contradictive res

Chongxing Yue, Gongru Lu, Qingjun Xu, Guoli Liu

In the framework of topcolor-assisted technicolor (TC2) theory, we calculate the contributions of the scalars(the neutral top-pion $π_{t}^{0}$ and the top-Higgs $h_{t}^{0}$) to the flavor-changing rare top decays $t\to c V V$(V= W, g, $γ$ or Z). Our results show that $h_{t}^{0}$ can enhance the standard model $B_{r}^{SM}(t\longrightarrow cWW)$ by several ord

U. Aglietti

We present a sum rule relating the electron energy spectrum and the hadron mass distribution in semileptonic b -> u decays close to threshold. The relation found is free from non-perturbative effects and the theoretical error is expected to be O(5%). An experimental confirmation of this prediction can provide a check of the basic assumptions at the root of t

Mayeul Arminjon

That preferred-frame theory accounts for special relativity and reduces to it if the gravitation field cancels. Starting from an interpretation of gravity as a pressure force, it is based on just one scalar field. This scalar gives the relation between the flat &#34;background&#34; metric and the curved &#34;physical&#34; metric, due to an equivalence princi

James S. Graber

We re-express gravitational wave results in terms of post-Newtonian parameters. Using these expressions, and some simplifying assumptions, we compute that in a favorable case, i.e. a ten solar-mass black hole spiraling in to a 10^6 solar-mass black hole, LISA observations will be able to constrain at the 10% level or better a single combination of post-post-

V. L. Kalashnikov

The basics of the relativistic astrophysics including the celestial mechanics in weak field, black holes and cosmological models are illustrated and analyzed by means of Maple 6

Winfried Zimdahl, Alexander B. Balakin

We describe the ``deflationary&#39;&#39; evolution from an initial de Sitter phase to a subsequent Friedmann-Lema\^ıtre-Robertson-Walker (FLRW) period as a specific non-equilibrium configuration of a self-interacting gas. The transition dynamics corresponds to a conformal, timelike symmetry of an ``optical&#39;&#39; metric, characterized by a refraction inde

T. R. Mongan

A simple and surprisingly realistic model of the origin of the universe can be developed using the Friedmann equation from general relativity, elementary quantum mechanics, and the experimental values of h, c, G and the proton mass. The model assumes there are N space dimensions (with N > 6) and the potential constraining the radius r of the invisible N -3 c

Victor Kromer

A two-parameter model of word length measured by the number of syllables comprising it is proposed. The first parameter is dependent on language type, the second one - on text genre and reflects the degree of completion of synergetic processes of language optimization.

Nobuhito Kokubo, Jan Aarts, Peter H. Kes

The sign change in the Hall conductivity has been studied in thin amorphous Nb$_{1-x}$Ge$_x (x\approx$0.3) films. By changing the film thickness it is shown that the field at which the sign reversal occurs shifts to lower values (from above to below the mean-field transition field $H_{c2}$) with increasing film thickness. This effect can be understood in ter

Cinzia De Leo, Giacomo Rotoli, Paola Barbara, A. P. Nielsen

We simulate two-dimensional Josephson junction arrays, including full mutual- inductance effects, as they are cooled below the transition temperature in a magnetic field. We show numerical simulations of the array magnetization as a function of position, as detected by a scanning SQUID which is placed at a fixed height above the array. The calculated magneti

A. Brinkman, D. Mijatovic, G. Rijnders, V. Leca

Superconducting thin films have been prepared on Si-substrates, using pulsed laser deposition from a target composed of a mixture of Mg and MgB2 powders. The films were deposited at room temperature and post-annealed at 600 degrees C. The zero resistance transition temperatures were 12 K, with an onset transition temperature of 27 K. Special care has been ta

G. Favrin, E. Marinari, F. Martinelli

We consider the 2D Ising lattice gas in a square of side L with free boundary conditions, temperature below the critical one and particle density slightly above the density of the vapor phase. Typical configurations consist of a quarter of a Wulff droplet of the liquid phase centered at one of the corners of the given square. We then introduced a reversible

Monique Combescot, Christian Tanguy

Dimensional arguments lead to say that $N$ excitons in a sample of volume $V$ behave as bosons for $λN a_x^3/V \ll 1$, $a_x$ being the exciton radius and $λ$ a dimensionless factor. The Mott criterion, which is based on the disappearance of all exciton bound states because of screening, gives $λ\simeq 1$. Since excitons feel each other through both Coulomb i

S. I. Schlachter, U. Tutsch, W. H. Fietz, K. -P. Weiss

In YBa2Cu3Ox, distinct features are found in the pressure dependence of the transition temperature, dTc/dp, and in DeltaCp*Tc, where DeltaCp is the jump in the specific heat at Tc: dTc/dp becomes zero when DeltaCp*Tc is maximal, whereas dTc/dp has a peak at lower oxygen contents where DeltaCp*Tc vanishes. Substituting Nd for Y and doping with Ca leads to a s

H. T. C. Stoof, E. Vliegen, U. Al Khawaja

We show that an antiferromagnetic spin-1 Bose-Einstein condensate, which can for instance be created with Na-23 atoms in an optical trap, has not only singular line-like vortex excitations, but also allows for singular point-like topological excitations, i.e., &#39;t Hooft-Polyakov monopoles. We discuss the static and dynamic properties ofthese monopoles.

D. Carpentier, C. Peca, L. Balents

We study tunneling between two nearby cleaved edge quantum wires in a perpendicular magnetic field. Due to Coulomb forces between electrons, the wires form a strongly-interacting pair of Luttinger liquids. We calculate the low-temperature differential tunneling conductance, in which singular features map out the dispersion relations of the fractionalized qua

P. C. Howell, A. J. Schofield

We study an exactly-solvable model which shows a zero-temperature transition from a non-Fermi liquid to a Fermi liquid as a function of particle density. The quantum critical point separating these two states is not associated with the usual ordering transition of a bosonic degree of freedom. We analyze the properties of this critical point in terms of an ef

E. Bascones, F. Guinea

Metals with many bands at the Fermi level can have different band dependent gaps in the superconducting state. The absence of translational symmetry at an interface can induce interband scattering and modify the superconducting properties. We dicuss the relevance of these effects to recent experiments in MgB$_2$.

Z. Fang, K. Terakura, J. Kanamori

Double perovskites Sr$_2$FeMO$_6$ (M=Mo and Re) exhibit significant colossal magnetoresistance even at room temperature due to the high Curie Temperature (419K and 401K). However, such a high Curie Temperature is puzzling, given the large separation between magnetic elements (Fe). Moreover, with M=W, the electronic and magnetic properties suddenly change to

Liat Ein-Dor, Ido Kanter, Wolfgang KJinzel

The interplay between the ground state energy of the generalized Bernasconi model to multi-phase, and the minimal value of the maximal autocorrelation function, $C_{max}=\max_K{|C_K|}$, $K=1,..N-1$, is examined analytically and the main results are: (a) The minimal value of $\min_N{C_{max}}$ is $0.435\sqrt{N}$ significantly smaller than the typical value for

P. Samuely, P. Szabo, T. Klein, A. G. M. Jansen

Elastic tunneling is used as a powerful direct tool to determine the upper critical field $H_{c2}(T)$ in the high-$T_c$ oxide Ba$_{1-x}$K$_x$BiO$_3$. The temperature dependence of $H_{c2}$ inferred from the tunneling follows the Werthamer-Helfand-Hohenberg prediction for type-II superconductors. A comparison will be made with resistively determined critical

V. K. Dugaev, A. Crepieux, P. Bruno

We calculate the localization corrections to the anomalous Hall conductivity related to the contribution of spin-orbit scattering into the current vertex (side-jump mechanism). We show that in contrast to the ordinary Hall effect, there exists a nonvanishing localization correction to the anomalous Hall resistivity. The correction to the anomalous Hall condu

Y. Wang, T. Plackowski, A. Junod

The specific heat C of a sintered polycrystalline sample of MgB2 with a bulk superconducting transition temperature Tc=36.7 K is measured as a function of the temperature (2-300 K) and magnetic field (0-16 T), together with magnetic properties (normal-state susceptibility, superconducting state magnetization, etc.). The Sommerfeld constant gamma=0.89+-0.05 m

T. Jarlborg

Spin-polarized band calculations for supercells of SrB$_{6}$, where a La-, In- or Al- impurity or a vacancy is replacing one Sr, are performed within the local spin density approximation. Moderately large cells with 8 formula units (56 atoms) are studied for all dopings and large ones with 27 formula units (189 atoms) for the case of La-doping. The undoped s

Maxim G. Vavilov, Igor L. Aleiner

We develop a time dependent random matrix theory describing the influence of a time-dependent perturbation on mesoscopic conductance fluctuations in open quantum dots. The effect of external field is taken into account to all orders of perturbation theory, and our results are applicable to both weak and strong fields. We obtain temperature and magnetic field

Kijoon H. P. Kim, W. N. Kang, Mun-Seog Kim, C. U. Jung

If the critical current density Jc is very high for a superconductor, then estimating its value from transport measurements is not very easy. In such cases, the value of Jc, called Jcm for magnetic Jc, is usually obtained from the measured magnetic hysteresis loop measurements by using a proper critical state model such as Bean&#39;s model (ref. 1). However,

Jai Seok Ahn, Eun Jip Choi

We investigated carbon substitution effect on boron plane of superconducting MgB$_2$. MgB$_2$ and MgB$_{1.8}$C$_{0.2}$ samples are synthesized under high pressure furnace. MgB$_{1.8}$C$_{0.2}$ are characterized as AlB$_2$-type single phase with smaller B-B distance. During the superconducting transition, two distinct onset temperatures are observed in MgB$_{

Y. P. Sun, W. H. Song, J. M. Dai, B. Zhao

This paper has been withdrawn by the author(s) because some experimental results have not been checked by the last two authors.

Uwe R. Fischer, Nils Schopohl

We compare dynamical and energetical stability criteria for vortex rings. It is argued that vortex rings will be intrinsically unstable against perturbations with short wavelengths below a critical wavelength, because the canonical vortex Hamiltonian is unbounded from below for these modes. To explicitly demonstrate this behaviour, we derive the oscillation

M. E. Putman

The results of the interaction between the Milky Way and the Magellanic Clouds are revealed through several high velocity complexes which are connected to the Clouds. The exact mechanism of their formation is under some debate, but they remain the only group of high-velocity clouds (HVCs) for which we have an origin and roughly a distance. Given that, the Ma

David B. Cline

We describe the Neutrino Spectrum and detection for SN II sources. We discuss the effects of neutrino mixing in the SN II. A new analysis of SN1987A is described. We discuss the possible detection of the diffuse relic SN II flux. Finally we discuss a new detection concept, OMNIS, for Nu sub mu and Nu sub tau and detection and compare with other present and f

David B. Cline

We review some of the expectations for Primordial Black Hole evaporation and we review the properties of short Gamma Ray Bursts. It is plausible that these GRB come from PBH evaporation. We then show that the angular distribution asymmetry recently observed by us could be due to a concentration of PBH in the Galactic Arms like the Orion arm.

Brian L. Rachford, Theodore P. Snow, Jason Tumlinson, J. Michael Shull

We report the second study from the FUSE survey of molecular hydrogen in translucent clouds, for the line of sight toward HD 110432. This star lies beyond the Coalsack dark nebula, and with E(B-V) = 0.40, and A_V = 1.32 this line of sight bridges the gap between less extinguished diffuse cloud lines of sight with A_V \sim 1, such as Zeta Oph, and the translu

Ravi Sankrit, Kenneth Wood

We present a three dimensional radiative transfer model to examine the effects of resonance line scattering in the post-shock flow behind a non-radiative supernova remnant shock. For a rippled shock front viewed edge-on, line scattering significantly reduces the observed flux of CIV 1549 and NV 1240, two important diagnostic lines in the ultraviolet spectra

Nelson Christensen, Renate Meyer, Lloyd Knox, Ben Luey

We present a strategy for a statistically rigorous Bayesian approach to the problem of determining cosmological parameters from the results of observations of anisotropies in the cosmic microwave background. Our strategy relies on Markov chain Monte Carlo methods, specifically the Metropolis-Hastings algorithm, to perform the necessary high-dimensional integ

Allen V. Sweigart

We discuss the impact of mixing and rotation along the red-giant branch (RGB) on the properties of horizontal-branch (HB) stars with emphasis on two problems: the nature of the unexpected blue HB population in the metal-rich globular clusters (GCs) NGC 6388 and NGC 6441 and the cause of the low gravities in the blue HB stars. New stellar models indicate that

A. Ford, R. D. Jeffries, D. J. James, J. R. Barnes

Lithium abundances, radial velocities and rotational velocities are reported for 20 candidate F, G and K stars of the sparse Coma Berenices open cluster. All the stars are proper-motion selected, and our radial velocities support the membership credentials of at least 12 of the candidates. Combining our data with that in the literature, we have a close-to-co

B. T. Gaensicke, G. D. Schmidt, S. Jordan, P. Szkody

Phase-resolved HST/STIS ultraviolet spectroscopy of the high-field polar AR UMa confirms that the WD photospheric Ly alpha Zeeman features are formed in a magnetic field of ~200 MG. In addition to the Ly alpha pi and sigma+ components, we detect the forbidden hydrogen 1s0->2s0 transition, which becomes ``enabled&#39;&#39; in the presence of both strong magne

Guinevere Kauffmann, Stephane Charlot, Michael L. Balogh

We explore a model in which efficient star formation in galaxies is triggered by merging satellites. We show that the merger/interaction rates predicted by hierarchical galaxy formation models depend strongly on galaxy mass. If a merger of a satellite larger than 1% the mass of the primary triggers efficient star formation, low-mass dwarf galaxies experience

S. C. Tripathy, Brajesh Kumar, Kiran Jain, A. Bhatnagar

Using intermediate degree p mode frequency data sets for solar cycle 22, we find that the frequency shifts and magnetic indices show a `hysteresis&#39; phenomenon. It is observed that the magnetic indices follow different paths for the ascending and descending phases of the solar cycle, the descending path always seems to follow a higher track than the ascen

Marek Nikolajuk, Bozena Czerny

We test the disk/corona model of Janiuk et al. (2000) against the composite mean optical/UV/soft X-ray spectrum of radio loud and radio quiet quasars from Laor et al. (1997) which applies to faint quasars. The model well represents the optical/UV continuum if the hardening of the locally emitted spectrum is included, with the color to effective temperature r

Enrique Gaztanaga, David H. Hughes

Hughes & Gaztanaga (2001, see article in these proceedings) have presented realistic simulations to address key issues confronting existing and forthcoming submm surveys. An important aspect illustrated by the simulations is the effect induced on the counts by the sampling variance of the large-scale galaxy clustering. We find factors of up to 2-4 variation

Carl Heiles

We present new Arecibo 21-cm line measurements of the temperatures of interstellar gas. Our temperatures for the Cold Neutral Medium (CNM) are significantly lower than previous single-dish results and in very good accord with theoretical models. For warm gas at T > 500 K, we find a significant fraction of gas (>47%) to lie in the thermally unstable region 50

Cornelia C. Lang, W. M. Goss, Luis F. Rodriguez

The Galactic center Arches stellar cluster, detected and studied until now only in the near-infrared, is comprised of at least one hundred massive (M>20 Msun) stars. Here we report the detection at centimeter wavelengths of radio continuum emission from eight radio sources associated with the cluster. Seven of these radio sources have rising spectral indices

Seong Chan Park, H. S. Song

We study the effects of extra dimension on the muon anomalous magnetic moment in the stabilized Randall-Sundrum scenario. The effects of the Kaluza-Klein states heavier than the cut-off scale expected to be of order $Λ_π$ are neglected. Contribution from the spin-2 Kaluza-Klein states dominates over that from the spin-0 radion. The recent BNL E821 results im

Patrick Dorey, Clare Dunning, Roberto Tateo

The one-dimensional Schrodinger equation for the potential $x^6+\alpha x^2 +l(l+1)/x^2$ has many interesting properties. For certain values of the parameters l and alpha the equation is in turn supersymmetric (Witten), quasi-exactly solvable (Turbiner), and it also appears in Lipatov's approach to high energy QCD. In this paper we signal some further curious

Mark J. Bowick, A. Cacciuto, G. Thorleifsson, A. Travesset

We determine the Poisson ratio of self-avoiding fixed-connectivity membranes, modeled as impenetrable plaquettes, to be sigma=-0.37(6), in statistical agreement with the Poisson ratio of phantom fixed-connectivity membranes sigma=-0.32(4). Together with the equality of critical exponents, this result implies a unique universality class for fixed-connectivity

Paolo Zanardi

The physical resources available to access and manipulate the degrees of freedom of a quantum system define the set $\cal A$ of operationally relevant observables. The algebraic structure of $\cal A$ selects a preferred tensor product structure i.e., a partition into subsystems. The notion of compoundness for quantum system is accordingly relativized. Univer