March 2001 arXiv papers — page 25

R. Gilli, G. Risaliti, P. Severgnini, R. Maiolino

We propose a classification scheme for the circumnuclear medium of AGNs based on their location in the A_V - N_H plane (related to dust absorption and gas absorption, respectively). We present evidence that the A_V/N_H ratio is often lower than the Galactic value. This is shown by the broad line ratios of a sample of intermediate Seyferts, and by the optical

Letizia Stanghellini, Richard A. Shaw, Max Mutchler

Planetary Nebulae (PNs) in the Magellanic Clouds are studied to understand stellar populations and evolution of low- and intermediate-mass stars in different chemical environments. Using HST observations from our LMC and SMC PN morphological survey and from the HST Data Archive, we look at the relations between PN morphology and their evolution and populatio

K. Jahnke, B. Kuhlbrodt, E. Orndahl, L. Wisotzki

We investigate multicolour imaging data of a complete sample of low redshift (z<0.2) QSO host galaxies. The sample was imaged in four optical (BVRi) and three near-infrared bands (JHKs), and in addition spectroscopic data is available for a majority of the objects. We extract host luminosities for all bands by means of two-dimensional modeling of galaxy and

D. Heck

When high-energy cosmic rays (gamma&#39;s, protons, or heavy nuclei) impinge onto the Earth&#39;s atmosphere, they interact at high altitude with the air nuclei as targets. By repeated interaction of the secondaries an `extensive air shower&#39; (EAS) is generated with huge particle numbers in the maximum of the shower development. Such cascades are quantita

Timothy A. D. Paglione, W. F. Wall, Judith S. Young, Mark H. Heyer

We present spectra of the extended 12CO and 13CO J=1-0 emission along the major axes of 17 nearby galaxies. Spatial variations in the ratio of CO and 13CO integrated intensities, R, are found in nearly every galaxy observed. There is an overall variation in R of 20-40% from the inner 2 kpc to the disk. Roughly a third of the survey galaxies have such gradien

S. Fabrika, A. Mescheryakov

The SS433 objects is a well-known source of relativistic jets, which are formed in supercritical accretion disk. It is very probable that the disk has polar channels and their radiation is collimated (the photocones). The face-on SS433 object can appear as beamed ultra-bright (and highly variable) X-ray source, L_x = 10^39 - 10^42 erg/s. We discuss propertie

E. Palladino, L. Amendola

We present the results from the correlation analysis of two galactic redshift surveys, the extended CfA2+SSRS2 and the slice centered on $δ=-12^{\circ}$ of Las Campanas. Furthermore, we evaluate the likelihood confidence regions for the CDM model and for the fractal model parameters. Our results indicate that, although the CDM model is in good agreement with

M. G. Richer, A. Bullejos, J. Borissova, Marshall L. McCall

We present optical spectroscopy of H {\sc ii} regions in the Local Group galaxy IC 10 and $UBVR$ photometry of foreground stars in three fields towards this galaxy. From these data, we find that the foreground reddening due to the Milky Way is $E(B-V)=0.77\pm 0.07 \mathrm{mag}$. We find that IC 10 contains considerable internal dust, which qualitatively expl

A. Moro-Martin, A. Noriega-Crespo, S. Molinari, L. Testi

The Cepheus E outflow has been studied in the mid and far infrared using the ISO CAM and LWS instruments, and at millimetric wavelengths using OVRO. In the near and mid-IR, its morphology is similar to that expected for a jet driven outflow, where the leading bow shocks entrain and accelerate the surrounding molecular gas. As expected, fine structure atomic/

B. J. Boyle, S. M. Croom, R. J. Smith, T. Shanks

We present some initial results from the 2dF QSO redshift survey. The aim of the survey is to produce an optically-selected catalogue of 25000 QSOs over the redshift range 0<z<3 using the 2-degree field at the Anglo-Australian Telescope.

Frank D. Steffen, Markus H. Thoma

The recent status of hard thermal photon production in relativistic heavy ion collisions is reviewed and the current rates are presented with emphasis on corrected bremsstrahlung processes in the quark-gluon plasma (QGP) and quark-hadron duality. Employing Bjorken hydrodynamics with an EOS supporting the phase transition from QGP to hot hadron gas (HHG), the

S. V. Vadawale, A. R. Rao, A. Nandi, S. K. Chakrabarti

We investigate the connection between the X-ray and radio properties of the Galactic microquasar GRS1915+105, by analyzing the X-ray data observed with RXTE, during the presence of a huge radio flare (~450 mJy). The X-ray lightcurve shows two dips of ~100 second duration. Detailed time resolved spectral analysis shows the existence of three spectral componen

Tadashi Takayanagi

We study tachyon condensation on brane-antibrane systems in orbifold theories from the viewpoint of boundary string field theory. We show that the condensation of holomorphic tachyon fields generates various fractional D-branes. The boundary N=2 supersymmetry in the world-sheet theory ensures this result exactly. Furthermore, our results are consistent with

Alex Buchel, Andrew Frey

Maldacena and Nunez [hep-th/0008001] identified a gravity solution describing pure N=1 Yang-Mills (YM) in the IR. Their (smooth) supergravity solution exhibits confinement and the U(1)_R chiral symmetry breaking of the dual YM theory, while the singular solution corresponds to the gauge theory phase with unbroken U(1)_R chiral symmetry. In this paper we disc

Zhiguang Xiao, Hanqing Zheng

Systematic and careful studies are made on the properties of the IJ=00 $ππ$ and $K\bar K$ coupled-channel system, using newly derived dispersion relations between the phase shifts and poles and cuts. The effects of nearby branch point singularities to the determination of the $f_0(980)$ resonance are estimated and and discussed.

R. Arun, G. S. Agarwal

We examine the passage of ultra-cold two-level atoms through the potential produced by the vacuum of the cavity field. The peak of the transmitted wave packet generally occurs at the instant given by the expression for phase time even if that instant is earlier than the instant at which incident wave packet&#39;s peak enters the cavity and thus the phase tim

Qiong-gui Lin

We consider the scattering of nonrelativistic particles in three dimensions by a contact potential $Ω\hbar^2δ(r)/ 2μr^α$ which is defined as the $a\to 0$ limit of $Ω\hbar^2δ(r-a)/2μr^α$. It is surprising that it gives a nonvanishing cross section when $α=1$ and $Ω=-1$. When the contact potential is approached by a spherical square well potential instead of t

Qiong-gui Lin

We study a relativistic charged Dirac particle moving in a rotating magnetic field. By using a time-dependent unitary transformation, the Dirac equation with the time-dependent Hamiltonian can be reduced to a Dirac-like equation with a time-independent effective Hamiltonian. Eigenstates of the effective Hamiltonian correspond to cyclic solutions of the origi

Shayan Mookherjea, Amnon Yariv

We review and extend the analogies between Gaussian pulse propagation and Gaussian beam diffraction. In addition to the well-known parallels between pulse dispersion in optical fiber and CW beam diffraction in free space, we review temporal lenses as a way to describe nonlinearities in the propagation equations, and then introduce further concepts that permi

Yu-Gang Ma

The features of the emissions of light particles ($LP$), charged particles ($CP$), intermediate mass fragments ($IMF$) and the largest fragment ($MAX$) are investigated for $^{129}Xe$ as functions of temperature and &#34;freeze-out&#34; density in the frameworks of isospin dependent lattice gas model and classical molecular dynamics model. Definite turning p

Y. H. Tan, H. Shen, P. Z. Ning

The quark mean field model, which describes the nucleon using the constituent quark model, is applied to investigate the properties of finite nuclei. The couplings of the scalar and vector mesons with quarks are made density dependent through direct coupling to the scalar field so as to reproduce the relativistic Brueckner-Hartree-Fock results of nuclear mat

Shigeki Matsutani

Discrete Lotka-Volterra equation over $p$-adic space was constructed since $p$-adic space is a prototype of spaces with the non-Archimedean valuations and the space given by taking ultra-discrete limit studied in soliton theory should be regarded as a space with the non-Archimedean valuations in the previous report (solv-int/9906011). In this article, using

Liviu I. Nicolaescu

We prove that the Seiberg-Witten invariants of a rational homology sphere are determined in a very explicit fashion by the Casson-Walker invariant and the Reidemeister torsion

Vyacheslav S. Krushkal, Ronnie Lee

Even though the disk embedding theorem is not available in dimension 4 for free fundamental groups, some surgery problems may be shown to have topological solutions. We prove that surgery problems may be solved if one considers closed 4-manifolds and the intersection pairing is extended from the integers, and prove a related splitting result.

Drazen Adamovic

Let $N_{k} (\g)$ be a vertex operator algebra (VOA) associated to the generalized Verma module for affine Lie algebra of type $A_{\ell -1} ^{(1)}$ or $C_{\ell} ^{(1)}$. We construct a family of ideals $J_{m,n} (\g)$ in $N_{k} (\g)$, and a family $V_{m,n} (\g)$ of quotient VOAs. These families include VOAs associated to the integrable representations, and VOA

Paul Seidel

We consider symplectic Floer homology in the lowest nontrivial dimension, that is to say, for area-preserving diffeomorphisms of surfaces. Particular attention is paid to the quantum cap product; we show that it distinguishes the trivial element of the mapping class group from any nontrivial one.

Kazuto Oshima

Spontaneous symmetry breaking in (1+1)-dimensional $ϕ^{4}$ theory is studied with discretized light-front quantization. Taking effects of non-diagonal interactions into account, the first few terms of the commutation relations $[a_{0},a_{n}]$ are recalculated in the $\hbar$ expansion. Our result of the critical coupling is still consistent with the equal-tim

A. I. Bugrij

The correlation function of two dimensional Ising model with the nearest neighbours interaction on the finite size lattice with the periodical boundary conditions is derived. The expressions similar to the form factor representation are obtained both for the ferromagnetic and paramagnetic regions of coupling constant. The peculiarities caused by the finite s

Shmuel Nussinov, Robert Shrock

We discuss the high-energy behavior of cross sections in theories with large extra dimensions and low-scale quantum gravity, addressing two particular issues: (i) the tension of the D-branes, and (ii) bounds on the cross section and their relation to approximations in the mode sum over Kaluza-Klein-graviton exchanges.

Tai-Fu Feng, Xue-Qian Li, Guo-Li Wang

Complete expressions of the $\bar{s}bg$ and $\bar{s}bγ$ vertices are derived in the framework of supersymmetry with minimal flavor violation. With the minimal supergravity (mSUGRA) model, a numerical analysis of the supersymmetric contributions to the Wilson Coefficients at the weak scale is presented.

I. A. Korzhavina

The first measurement of D*+/- meson diffractive photoproduction cross sections has been performed with the ZEUS detector at the HERA $ep$ collider, using an integrated luminosity of 38 pb^-1. The measurement has been performed for photon--proton center-of-mass energies in the range 130 < W < 280 GeV and photon virtualities Q^2 < 1 GeV^2. D*+/- mesons have b

Mohammad Khorrami, Amir Aghamohammadi

The Glauber model on a one-dimensional lattice with boundaries (for the ferromagnetic- and anti-ferromagnetic case) is considered. The large-time behaviour of the one-point function is studied. It is shown that, for any positive temperature, the system shows a dynamical phase transition. The dynamical phase transition is controlled by the rate of spin flip a

D. A. Ivanov

In disordered vortices in p-wave superconductors the two new random-matrix ensembles may be realized: B and DIII-odd (of so(2N+1) and so(4N+2)/u(2N+1) matrices respectively). We predict these ensembles from an explicit analysis of the symmetries of Bogoliubov-deGennes equations in three examples of vortices with different p-wave order parameters. A character

A. V. Kornilov, V. M. Pudalov, Y. Kitaoka, K. Ishida

Magnetoresistance measurements on the quasi one-dimensional organic conductor (TMTSF)_2PF_6 performed in magnetic fields B up to 16T, temperatures T down to 0.12K and under pressures P up to 14kbar have revealed new phases on its P-B-T phase diagram. We found a new boundary which subdivides the field induced spin density wave (FISDW) phase diagram into two r

J. Wakou, R. Brito, M. H. Ernst

In this paper we show how, under certain restrictions, the hydrodynamic equations for the freely evolving granular fluid fit within the framework of the time dependent Landau-Ginzburg (LG) models for critical and unstable fluids (e.g. spinodal decomposition). The granular fluid, which is usually modeled as a fluid of inelastic hard spheres (IHS), exhibits tw

Vanja Dunjko, Vincent Lorent, Maxim Olshanii

We present a quantitative analysis of the experimental accessibility of the Tonks-Girardeau gas in the current day experiments with cigar-trapped alkalis. For this purpose we derive, using a Bethe anzats generated local equation of state, a set of hydrostatic equations describing one-dimensional delta-interacting Bose gases trapped in a harmonic potential. T

Verne V. Smith, Katia Cunha, Daniela Lazzaro

Abundances of 22 elements have been determined from a high-resolution, high signal-to-noise spectrum of HD19994, a star recently announced as harboring an extrasolar planet. A detailed spectroscopic analysis of this stars finds it to have a mass of 1.2+/-0.1Msun. HD19994 is found to be slightly enriched in &#34;metals&#34; relative to the Sun 9[Fe/H]=+0.09+/

Julian H. Krolik

For the past twenty-five years, nearly all analyses of accretion disk dynamics have assumed that stress inside the disk is locally proportional to pressure (the &#34;alpha-model&#34;) and that this stress goes to zero at the marginally stable orbit. Recently, it has been demonstrated that MHD turbulence accounts for the bulk of internal disk stress. In contr

D. Konenkov, U. Geppert

We apply the model of flux expulsion from the superfluid and superconductive core of a neutron star, developed by Konenkov & Geppert (2000), both to neutron star models based on different equations of state and to different initial magnetic field structures. When initially the core and the surface magnetic field are of the same order of magnitude, the rate o

Itziar Aretxaga, Elena Terlevich, Roberto Terlevich, Garret Cotter

We present optical spectra of the nuclei of seven luminous (P(178MHz) > 10**25 W Hz**(-1) Sr**(-1)) nearby (z<0.08) radiogalaxies, which mostly correspond to the FR II class. In two cases, Hydra A and 3C 285, the Balmer and 4000A break indices constrain the spectral types and luminosity classes of the stars involved, revealing that the blue spectra are domin

Isao Kishimoto

We explicitly construct noncommutative * products on circularly symmetric two dimensional space by using the technique of Fedosov's deformation quantization. Especially, on constant curvature spaces i.e., S^2 and H^2, we get su(2) and su(1,1) algebra respectively. These are candidates of * products applicable to noncommutative field theories or noncommutativ

Ph. Vanderbemden, H. Bougrine, M. Ausloos, R. Cloots

This paper aims at reporting magnetic properties of bulk polycrystalline Bi2Sr2Ca0.8Dy0.2Cu2O8-y samples textured under a magnetic field. The microstructure of these materials is highly anisotropic and exhibits particular features needed to be taken into account in order to interpret their magnetic and electrical properties. First the AC magnetic susceptibil

Mikhail Belolipetsky

We study groups generated by three half-turns in the Lobachevsky $3$-space and their quotient orbifolds. These generalized triangle groups are closely related to the arbitrary 2-generator Kleinian groups. Our main result is a classification of the singular sets of the generalized triangle orbifolds. We also present a method to obtain the parameters defining

Chao-Hsi Chang, Yu-Qi Chen, Guo-Li Wang, Hong-Shi Zong

The semileptonic decays, $B_{c}{\longrightarrow}{χ_c}(h_c)+{\ell}+{ν}_{\ell}$, and the two-body nonleptonic decays, $B_{c}{\longrightarrow}{χ_c}(h_c)+h$, (here $χ_c$ and $h_c$ denote $(c\bar c[^3P_J])$ and $(c\bar c[^1P_1])$ respectively, and $h$ indicates a meson) were computed. All of the form factors appearing in the relevant weak-current matrix elements

T. Takahashi, T. Sato, S. Souma, T. Muranaka

We have performed high-resolution photoemission spectroscopy on MgB2 and observed opening of a superconducting gap with a narrow coherent peak. We found that the superconducting gap is s-like with the gap value of 4.5 meV at 15 K. The temperature dependence (15 - 40 K) of gap value follows well the BCS form, suggesting that 2Delta/kBTc at T=0 is about 3. No

S. Kondratyuk, O. Scholten

A microscopic calculation of Compton scattering on the nucleon is presented which encompasses the lowest energies -- yielding nucleon polarizabilities -- and extends to energies of the order of 600 MeV. We have used the covariant &#34;Dressed K-Matrix Model&#34; obeying the symmetry properties which are appropriate in the different energy regimes. In particu

Peter F. Stadler, Anita Mehta, Jean-Marc Luck

We present a simple model of a vibrated box of sand, and discuss its dynamics in terms of two parameters reflecting static and dynamic disorder respectively. The fluidised, intermediate and frozen (`glassy&#39;) dynamical regimes are extensively probed by analysing the response of the packing fraction to steady, as well as cyclic, shaking, and indicators of

I. S. Beloborodov, A. V. Andreev

We study Coulomb blockade effects in the thermodynamic quantities of a weakly disordered metallic grain coupled to a metallic lead by a tunneling contact with a large conductance $g_T$. We consider the case of broken time-reversal symmetry and obtain expressions for both the {\em ensemble averaged} amplitude of the Coulomb blockade oscillations of the thermo

M. Fellhauer, H. Baumgardt, P. Kroupa, R. Spurzem

Interacting galaxies like the famous Antennae (NGC 4038/4039) or Stephan&#39;s Quintet (HCG 92) show considerable star forming activity in their tidal arms. High resolution images (e.g. from HST-observations) indicate that these regions consist of up to hundreds of massive stellar clusters or tidal dwarf galaxies (TDG). In this paper we want to investigate t

J. Casahorran

We consider the quantum tunneling phenomenon in a well-behaved triple-well potential. As required by the semiclassical approximation we take into account the quadratic fluctuations over the instanton which represents as usual the localised finite-action solution of the euclidean equation of motion. The determinants of the quadratic differential operators at

G. P. Berman, F. Borgonovi, F. M. Izrailev, V. I. Tsifrinovich

We show that a magnetic field gradient can suppress the onset of quantum chaos in a nuclear spin chain quantum computer.

G. P. Berman, G. W. Brown, M. E. Hawley, V. I. Tsifrinovich

We propose a solid-state nuclear spin quantum computer based on application of scanning tunneling microscopy (STM) and well-developed silicon technology. It requires the measurement of tunneling current modulation caused by the Larmor precession of a single electron spin. Our envisioned STM quantum computer would operate at the high magnetic field ($\sim 10$

G. P. Berman, G. D. Doolen, D. I. Kamenev, V. I. Tsifrinovich

We discuss how to simulate simple quantum logic operations with a large number of qubits. These simulations are needed for experimental testing of scalable solid-state quantum computers. Quantum logic for remote qubits is simulated in a spin chain. Analytical estimates are presented for possible correlated errors caused by non-resonant transitions. A range o

D. J. Millener

The structure of light nuclei out to the drip lines and beyond up to Z = 8 is interpreted in terms of the shell model. Special emphasis is given to the underlying supermultiplet symmetry of the p-shell nuclei which form cores for neutrons and protons added in sd-shell orbits. Detailed results are given on the wave functions, widths, and Coulomb energy shifts

D. Ueltschi

This review describes quantum systems of bosonic particles moving on a lattice. These models are relevant in statistical physics, and have natural ties with probability theory. The general setting is recalled and the main questions about phase transitions are addressed. A lattice model with Lennard-Jones potential is studied as an example of a system where f

Frank Calegari

Continuing on from recent results of Brumer-Kramer and of Schoof, we show that there exist non-zero semistable Abelian varieties over Z[1/N], with N squarefree, if and only if N is not in the set {1,2,3,5,6,7,10,13}. Our results are contingent on the GRH discriminant bounds of Odlyzko.

Thang Le, Vladimir Turaev

For a group G, the notion of a ribbon G-category was introduced by the second author in a previous work with a view towards constructing 3-dimensional homotopy quantum field theories (HQFT&#39;s) with target K(G,1). We discuss here how to derive ribbon G-categories from a simple complex Lie algebra g where G is the center of g. The construction is based on a

Carlo Mantegazza

We consider the gradient flow of hypersurfaces immersed in the Euclidean space associated to geometric energy functionals. We show that for particular functionals depending by higher covariant derivatives of the curvature, singularities in finite time cannot occur during the evolution. Such geometric functionals are related to similar ones proposed by Ennio

Ha Huy Tai

In this paper, we examine Green and Lazarsfeld&#39;s Np property for rational surfaces obtained by blowing up the projective plane P^2 at a subscheme of fat points Z. We show that these surfaces, embedded into projective spaces by linear system of plane curves of degree t containing Z, possess property Np for all t >> 0. This gives a positive answer to a con

Damien A. Easson, Robert H. Brandenberger

We point out that scenarios in which the universe is born from the interior of a black hole may not posses many of the problems of the Standard Big-Bang (SBB) model. In particular we demonstrate that the horizon problem, flatness, and the structure formation problem might be solved naturally, not necessarily requiring a long period of cosmological inflation.

Salvatore Mele

The values of the elements of the Cabibbo-Kobayashi-Maskawa matrix are constrained by direct and indirect measurements. A fit to experimental data and theory calculations allows the indirect determination of the vertex and angles of the unitarity triangle as: rho = 0.18 +/- 0.07 eta = 0.35 +/- 0.05 sin 2alpha = 0.14 +0.25 -0.38 sin 2beta = 0.73 +/- 0.07 gamm

T. M. Aliev, M. K. Cakmak, A. Ozpineci, M. Savci

Using the general, model independent form of the effective Hamiltonian, the general expressions of the longitudinal, normal and transversal polarization asymmetries for (l^-) and (l^+) and combinations of them for the exclusive (B -> K l^+ l^-) decay are found. The sensitivity of lepton polarizations and their combinations on new Wilson coefficients are stud

Bogdan A. Dobrescu

There is strong evidence that new physical degrees of freedom and new phenomena exist and may be revealed in future collider experiments. The best hints of what this new physics might be are provided by electroweak symmetry breaking. I briefly review certain theories for physics beyond the standard model, including the top-quark seesaw model and universal ex

V. A. Yerokhin, V. M. Shabaev

The one-loop self-energy correction to the hyperfine splitting of the 1s and 2s levels in H-like low-Z atoms is evaluated to all orders in Zα. The results are compared to perturbative calculations. The residual higher-order contribution is evaluated. Implications to the specific difference of the hyperfine structure intervals 8Δν_2 - Δν_1 in He^+ are investi

V. I. Bashkov, S. M. Kozyrev

Analyzing the static spherically symmetric and rotating ellipsoid solutions in the Newtonian limit of Jordan, Brance - Dicke theory we find the following. In empty space scalar-tensor theories have trivial solution of field equation with constant scalar potential (efficient value of gravitation constant). In this case no celestial-mechanical experiments to r

D. E. Segall, T. A. Arias, Alejandro Strachan, William A. Goddard

The Peierls stress for a [111]-screw dislocation in bcc Tantalum is calculated using an embedded atom potential. More importantly, a method is presented which allows accurate calculations of the Peierls stress in the smallest periodic cells. This method can be easily applied to ab initio calculations, where only the smallest unit cells capable of containing

M. D. Glinchuk, E. A. Eliseev, V. A. Stephanovich

We calculate the pyrocoefficient, static dielectric susceptibility profiles and its thickness dependence of ferroelectric thin films. Also, the temperature dependences of above quantities have been calculated. For the calculations we use Landau phenomenological theory, leading to Lame equations. These equations subject to boundary conditions with different e

Sarbpreet Singh, K. Dharamvir, V. K. Jindal

Depending on the temperature, the C70 solid crystallizes in several structures. At high temperature (T > 340K), the ellipsoidal C70 molecule rotates freely in all directions and may be treated as a uniform thick spherical shell with inner and outer radii as the minimum and the maximum distance of C-atom from the center of the molecule. At lower temperatures

Y. G. Zhao, X. P. Zhang, P. T. Qiao, H. T. Zhang

We report the preparation of Mg1-xLixB2 compounds. Nearly single phased samples were obtained for x<0.3. The in-plane lattice parameter a decreases with Li doping, while the lattice parameter c does not show obvious change. The superconducting transition temperature of Mg1-xLixB2 decreases with Li doping and loss of superconductivity occurs for x=0.5 sample.

W. P. Orrick, B. Nickel, A. J. Guttmann, J. H. H. Perk

We have made substantial advances in elucidating the properties of the susceptibility of the square lattice Ising model. We discuss its analyticity properties, certain closed form expressions for subsets of the coefficients, and give an algorithm of complexity O(N^6) to determine its first N coefficients. As a result, we have generated and analyzed series wi

C. B. Hanna, A. H. MacDonald, S. M. Girvin

Double-layer quantum Hall systems possess interlayer phase coherence at sufficiently small layer separations, even without interlayer tunneling. When interlayer tunneling is present, application of a sufficiently strong in-plane magnetic field $B_\parallel > B_c$ drives a commensurate-incommensurate (CI) transition to an incommensurate soliton-lattice (SL) s

S. Holland, J. P. U. Fynbo, J. Hjorth, J. Gorosabel

We present deep HST/STIS and ground-based photometry of the host galaxy of the gamma-ray burst GRB 980703 taken 17, 551, 710, and 716 days after the burst. We find that the host is a blue, slightly over-luminous galaxy with V_gal = 23.00 +/- 0.10, (V-R)_gal = 0.43 +/- 0.13, and a centre that is approximately 0.2 mag bluer than the outer regions of the galaxy

U. Torkelsson, G. I. Ogilvie, A. Brandenburg, J. E. Pringle

Warped, precessing accretion discs appear in a range of astrophysical systems, for instance the X-ray binary Her X-1 and in the active nucleus of NGC4258. In a warped accretion disc there are horizontal pressure gradients that drive an epicyclic motion. We have studied the interaction of this epicyclic motion with the magnetohydrodynamic turbulence in numeri

T. Shanks, B. J. Boyle, S. M. Croom, F. Hoyle

With ~10000 QSO redshifts, the 2dF QSO Redshift Survey (2QZ) is already the biggest individual QSO survey. The aim for the survey is to have ~25000 QSO redshifts, providing an order of magnitude increase in QSO clustering statistics. We first describe the observational parameters of the 2dF QSO survey. We then describe several highlights of the survey so far

M. J. Page, J. P. D. Mittaz, F. J. Carrera

We have surveyed 188 ROSAT PSPC fields for X-ray sources with hard spectra (alpha<0.5); such sources must be major contributors to the X-ray background at faint fluxes. In this paper we present optical identifications for 62 of these sources: 28 AGN which show broad lines in their optical spectra (BLAGN), 13 narrow emission line galaxies (NELGs), 5 galaxies

J. H. Fan, B. C. Qian, J. Tao

We present the optical (V, R, and I) photometry for BL Lacertae, which was observed from 1997 through 1999, with the 1.56-m telescope at the Shanghai astronomical observatory (SHAO). After the 1997 outburst, it dimmed to a low state and then brightened again. During the period JD 2450701 to JD 2450701.5, variations of 0.40mag, 0.27mag, and 0.21mag over a tim

Hu Zhan, Priya Jamkhedkar, Li-Zhi Fang

We analyze the power spectrum of a QSO&#39;s Ly_alpha transmitted flux in the discrete wavelet transform (DWT) representation. Although the mean DWT power spectrum is consistent with its counterpart in Fourier representation, the spatial distribution of the local power varies greatly, i.e. the local DWT power spectra show remarkably spiky structures on small

M. Y. Poon, D. Merritt

Orbital motion in triaxial nuclei with central point masses, representing supermassive black holes, is investigated. The stellar density is assumed to follow a power law, rho ~ 1/r^gamma, with gamma=1 or gamma=2. At low energies the motion is essentially regular; the major families of orbits are the tubes and the pyramids. Pyramid orbits are similar to box o

Martin B. Einhorn, J. Wudka

Assuming that the scale of new physics exceeds the weak scale, we have considered all possible origins of deviations from the Standard Model in $\gmu2$. If the underlying theory can be treated perturbatively, then to account for an effect as large as has been recently reported\cite{BNL}, the only possibilities would be models that contain particles that yiel

Steven C. Pieper, R. B. Wiringa

Accurate quantum Monte Carlo calculations of ground and low-lying excited states of light p-shell nuclei are now possible for realistic nuclear Hamiltonians that fit nucleon-nucleon scattering data. At present, results for more than 30 different (J^pi;T) states, plus isobaric analogs, in A \leq 8 nuclei have been obtained with an excellent reproduction of th

Edmond Iancu, Larry McLerran

We find approximate solutions to the renormalization group equation which governs the quantum evolution of the effective theory for the Color Glass Condensate. This is a functional Fokker-Planck equation which generates in particular the non-linear evolution equations previously derived by Balitsky and Kovchegov within perturbative QCD. In the limit where th

V. Giovannetti, S. Lloyd, L. Maccone

A wide variety of positioning and ranging procedures are based on repeatedly sending electromagnetic pulses through space and measuring their time of arrival. This paper shows that quantum entanglement and squeezing can be employed to overcome the classical power/bandwidth limits on these procedures, enhancing their accuracy. Frequency entangled pulses could

S. Hannestad, S. H. Hansen, F. L. Villante, A. J. S. Hamilton

We constrain the spectrum of primordial curvature perturbations by using recent Cosmic Microwave Background (CMB) and Large Scale Structure (LSS) data. Specifically, we consider CMB data from the COBE, Boomerang and Maxima experiments, the real space galaxy power spectrum from the IRAS PSCz survey, and the linear matter power spectrum inferred from Ly-alpha

S. Abel, S. Khalil, O. Lebedev

We analyze the possibility of simultaneous electron, neutron, and mercury electric dipole moment (EDM) cancellations in the mSUGRA and D--brane models. We find that the mercury EDM constraint practically rules out the cancellation scenario in D-brane models whereas in the context of mSUGRA it is still allowed with some fine-tuning.

Mario Nicodemi, Henrik Jeldtoft Jensen

There is mounting experimental evidence that strong off-equilibrium phenomena, such as ``memory&#39;&#39; or ``aging&#39;&#39; effects, play a crucial role in the physics of vortices in type II superconductors. We give a short review, based on a recently introduced schematic vortex model, of current progresses in understanding out of equilibrium vortex behav

Ruediger Kneissl, Michael E. Jones, Richard Saunders, Vincent R. Eke

We discuss prospects for cluster detection via the Sunyaev-Zel&#39;dovich (SZ) effect in a blank field survey with the proposed interferometer array, the Arcminute MicroKelvin Imager (AMI). Clusters of galaxies selected in the SZ effect probe cosmology and structure formation with little observational bias, because the effect directly measures integrated gas

Alexios P. Polychronakos

We propose a finite Chern-Simons matrix model on the plane as an effective description of fractional quantum Hall fluids of finite extent. The quantization of the inverse filling fraction and of the quasiparticle number is shown to arise quantum mechanically and to agree with Laughlin theory. We also point out the effective equivalence of this model, and the

Luis A. Anchordoqui, Haim Goldberg, Thomas J. Weiler

If, as recently proposed by Farrar and Piran, Cen A is the source of cosmic rays detected above the Greisen-Zatsepin-Kuz&#39;min cutoff, neutrons are $\approx 140$ more probable than protons to be observed along its line of sight. This is because the proton flux is rendered nearly isotropic by ${\cal O}(μ$G) intergalactic magnetic fields. With the anticipate

Tatsuo Kobayashi, Haruhiko Terao

We study soft SUSY breaking parameters in the Nelson-Strassler type of models: SUSY standard models coupled with SCFTs. In this type of models, soft SUSY breaking parameters including sfermion masses can be suppressed around the decoupling scale of SCFTs. We clarify the condition to derive exponential suppression of sfermion masses within the framework of pu

Ph. Bernard, G. Gemme, R. Parodi, E. Picasso

The design and test of a detector of small harmonic displacements is presented. The detector is based on the principle of the parametric conversion of power between the resonant modes of two superconducting coupled microwave cavities. The work is based on the original ideas of Bernard, Pegoraro, Picasso and Radicati, who, in 1978, suggested that superconduct

Lucian Anton, Hendrik B. Geyer

With a toppling rule which generates metastable sites, we explore the properties of a gradient-driven sandpile that is minimally perturbed at one boundary. In two dimensions we find that the transport of grains takes place along deep valleys, generating a set of patterns as the system approaches the stationary state. We use two versions of the toppling rule

V. Yu. Irkhin, A. V. Zarubin

The electron spectrum structure in the half-filled Hubbard model is considered in terms of the one-particle Green&#39;s functions within many-electron representation. A simple analytical generalization of the single-site Hubbard-III approximation is obtained, which takes into account the Fermi excitations (Kondo terms). The problem of the metal-insulator tra

Masashige Matsumoto, Mikito Koga

A new type of Kondo effect peculiar to unconventional superconductors is studied theoretically by using the Wilson&#39;s numerical renormalization group method. In this case, an angular momentum of a Cooper pair plays an important role in the Kondo effect. It produces multichannel exchange couplings with a local spin. Here we focus on a $p_x +i p_y$-wave sta

R. Hänninen, E. V. Thuneberg

Superfluid 3He-A has domain-wall-like structures, which are called solitons. We calculate numerically the structure of a splay soliton. We study the effect of solitons on the nuclear-magnetic-resonance spectrum by calculating the frequency shifts and the amplitudes of the soliton peaks for both longitudinal and transverse oscillations of magnetization. The e

L. Rezzolla, O. Zanotti

A Riemann problem with prescribed initial conditions will produce one of three possible wave patterns corresponding to the propagation of the different discontinuities that will be produced once the system is allowed to relax. In general, when solving the Riemann problem numerically, the determination of the specific wave pattern produced is obtained through

Hiraku Nakajima

In this article, we give geometric constructions of tensor products in various categories using quiver varieties. More precisely, we introduce a lagrangian subvariety $\Zl$ in a quiver variety, and show the following results: (1) The homology group of $\Zl$ is a representation of a symmetric Kac-Moody Lie algebra $\mathfrak g$, isomorphic to the tensor produ

Yuriy I. Kuzmin

The influence of geometry and morphology of superconducting structure on critical currents and magnetic flux trapping in percolative type-II superconductor is considered. The superconductor contains the clusters of a normal phase, which act as pinning centers. It is found that such clusters have significant fractal properties. The main features of these clus

J. Poirier, S. Roesler, A. Fasso&#39;

The FLUKA Monte Carlo program is used to predict the distributions of the muons which originate from primary cosmic gamma rays and reach sea level. The main result is the angular distribution of muons produced by vertical gamma rays which is necessary to predict the inherent angular resolution of any instrument utilizing muons to infer properties of gamma ra

Yonatan Zunger

We consider the addition of charged matter (``fundametals'') to noncommutative Yang-Mills theory and noncommutative QED, derive Feynman rules and tree-level potentials for them, and study the divergence structure of the theory. These particles behave very much as they do in the commutative theory, except that (1) they occupy bound-state wavefunctions which a

Arindam Mitra

The long-standing problem of quantum information processing is to remove the classical channel from quantum communication. Introducing a new information processing technique, it is discussed that both insecure and secure quantum communications are possible without the requirement of classical channel.