June 2004 arXiv papers — page 14

Leon A. Takhtajan, Lee-Peng Teo

We study the Hilbert manifold structure on $T_{0}(1)$ -- the connected component of the identity of the Hilbert manifold T(1). We characterize points on $T_{0}(1)$ in terms of Bers and pre-Bers embeddings, and prove that the Grunsky operators $B_{1}$ and $B_{4}$, associated with the points in $T_{0}(1)$ via conformal welding, are Hilbert-Schmidt. We define a

Ian Agol

Yair Minsky showed that punctured torus groups are classified by a pair of ending laminations (ν_-,ν_+). In this note, we show that there are ending laminations ν_+ such that for any choice of ν_-, the punctured torus group is transcendental as a subgroup of PSL_2 C.

Artem Zvavitch

The aim of this paper is to study properties of sections of convex bodies with respect to different types of measures. We present a formula connecting the Minkowski functional of a convex symmetric body K with the measure of its sections. We apply this formula to study properties of general measures most of which were known before only in the case of the sta

Yair Batal, Nathan Linial, Manor Mendel, Assaf Naor

Frechet's classical isometric embedding argument has evolved to become a major tool in the study of metric spaces. An important example of a Frechet embedding is Bourgain's embedding. The authors have recently shown that for every e>0 any n-point metric space contains a subset of size at least n^(1-e) which embeds into l_2 with distortion O(\log(2/e)

P. Freitas

We show that integrals of the form \[ \dint_{0}^{1} x^{m}{\rm Li}_{p}(x){\rm Li}_{q}(x)dx, (m\geq -2, p,q\geq 1) \] and \[ \dint_{0}^{1} \frac{\ds \log^{r}(x){\rm Li}_{p}(x){\rm Li}_{q}(x)}{\ds x}dx, (p,q,r\geq 1) \] satisfy certain recurrence relations which allow us to write them in terms of Euler sums. From this we prove that, in the first case for all $m

M. Kozlova, P. Salminen

In this paper we study a storage process or a liquid queue in which the input process is the local time of a positively recurrent stationary diffusion in stationary state and the potential output takes place with a constant deterministic rate. For this storage process we find its stationary distribution and compute the joint distribution of the starting and

Hélène Esnault

We give a proof of Artin's vanishing theorem in characteristic zero, based on Deligne's Riemann-Hilbert correspondence. Just as a curiosity.

I. Egorova, L. Golinskii

We study spectrum inclusion regions for complex Jacobi matrices which are compact perturbations of the discrete laplacian. The condition sufficient for the lack of discrete spectrum for such matrices is given.

Ronald L. Graham, Boris D. Lubachevsky

We examine sequences of dense packings of n congruent non-overlapping disks inside a square which follow specific patterns as n increases along certain values, n = n(1), n(2),... n(k),.... Extending and improving previous work of Nurmela and Ostergard where previous patterns for n = n(k) of the form k*k, k*k-1, k*k-3, k(k+1), and 4k*k+k were observed, we ide

Jean Bertoin, Alexander Gnedin

We consider a self-similar fragmentation process in which the generic particle of size $x$ is replaced at probability rate $x^α$, by its offspring made of smaller particles, where $α$ is some positive parameter. The total of offspring sizes may be both larger or smaller than $x$ with positive probability. We show that under certain conditions the typical siz

Leon A. Takhtajan, Lee-Peng Teo

We prove that the universal Teichmuller space T(1) carries a new structure of a complex Hilbert manifold. We show that the connected component of the identity of T(1), the Hilbert submanifold T_{0}(1), is a topological group. We define a Weil-Petersson metric on T(1) by Hilbert space inner products on tangent spaces, compute its Riemann curvature tensor, and

M. Baillif, V. Baladi

Transfer operators M_k acting on k-forms in R^n are associated to smooth transversal local diffeomorphisms and compactly supported weight functions. A formal trace is defined by summing the product of the weight and the Lefschetz sign over all fixed points of all the diffeos. This yields a formal Ruelle-Lefschetz determinant Det^#(1-zM). We use the Milnor-Ru

Susumu Tanabé

We calculate the fibre integrals of the hypersurface in a torus in the form of their Mellin transforms. Especially, our method works efficiently for an affine hypersurface defined by a so called simpliciable polynomial. The relations between poles of Mellin transforms of fibre integrals, the mixed Hodge structure of the cohomology of the hypersurface, the hy

C. Kristjansen, T. Mansson

We complete the description of the circular, elliptic three spin string on AdS_5 x S^5 having three large angular momenta (J_1,J_2,J_3) on S^5 in the language of the integrable SU(3) spin chain. First, we recover the string solution directly from the spin chain sigma model and secondly, we identify the appropriate Bethe root configuration in the so far unexp

David A. Kosower

Using the novel diagrammatic rules recently proposed by Cachazo, Svrcek, and Witten, I give a compact, manifestly Lorentz-invariant form for tree-level gauge-theory amplitudes with three opposite helicities.

Anais Smailagic, Euro Spallucci

Ultraviolet finite quantum field theory on even dimensional noncommutative spacetime is formulated using coordinate coherent states. 2d spacetime is foliated into families of orthogonal, non commutative, two-planes. Lorentz invariance is recovered if one imposes a single non commutative parameter theta in the theory. Unitarity is checked at the one-loop leve

B. de Carlos, J. Roberts, Y. Schmohe

We study cosmological solutions in the context of 4-dimensional low energy Heterotic M-theory with moving bulk branes. In particular we present non-trivial, analytic axion solutions generated by new symmetries of the full potential-free action which are similar to 'triple axion' solutions found in Pre-Big-Bang (PBB) cosmologies. We also consider the

Tanay Kr. Dey

We construct asymptotically anti-deSitter (and deSitter) black hole solutions of Einstein-Born-Infeld theory in arbitrary dimension. We critically analyse their geometries and discuss their thermodynamic properties.

Juha Honkonen, M. V. Komarova, M. Yu. Nalimov

Instanton analysis is applied to model A of critical dynamics. It is shown that the static instanton of the massless $ϕ^{4}$ model determines the large-order asymptotes of the perturbation expansion of the dynamic model.

Kazuyuki Furuuchi

We present a method to construct matrix models on arbitrary simply connected oriented real two dimensional Riemannian manifolds. The actions and the path integral measure are invariant under holomorphic transformations of matrix coordinates.

Michael T. Anderson

We discuss classical gravitational aspects of the AdS/CFT correspondence, with the aim of obtaining a rigorous (mathematical) understanding of the semi-classical limit of the gravitational partition function. The paper surveys recent progress in the area, together with a selection of new results and open problems.

Chongxing Yue, Wei Wang, Feng Zhang

Taking into account the constraints of the present experimental limit of the process $μ\to eγ$ on the free parameters of topcolor-assisted technicolor(TC2) models, we calculate the contributions of the neutral top-pion to the lepton flavor violating(LFV) $Z$ decays $Z\to l_{i}l_{j}$. Our results show that the value of the branching ratio $Br(Z\to τl)$ is lar

Patricia Ball, Roman Zwicky

We present an improved calculation of $B\to$ light pseudoscalar formfactors from light-cone sum rules, including one-loop radiative corrections to twist-2 and twist-3 contributions, and leading order twist-4 corrections. The total theoretical uncertainty of our results at zero momentum transfer is 10 to 13% and can be improved, at least in part, by reducing

Benjamin Portheault

We present a preliminary account of a new global QCD analysis of DIS data, including recent $ν, \bar ν$ DIS measurements. The model-independent cross section reanalysis by CCFR allows a new determination of the strange sea asymmetry, whose first moment is found to be small. The impact on the NuTeV measurement of $\sin^2 θ_W$ is discussed.

Antoni Szczurek, Marta Czech

The inclusive distributions of gluons and pions for high-energy NN collisions are calculated. The results for several unintegrated gluon distributions (UGD's) from the literature are compared. We find huge differences in both rapidity and $p_t$ of gluons and $π$'s in NN collisions for different models of UGD's. The Karzeev-Levin UGD gives good de

Wei-Min Yang, Zhi-Gang Wang

we study fermion masses and flavor mixing in a supersymmetric SO(10) model, where $\mathbf{10}$, $\mathbf{120}$ and $\mathbf{\bar{126}}$ Higgs multiplets have Yukawa couplings with matter multiplets and give masses to quarks and leptons through the breaking chain of a Pati-Salam group. This brings about that, at the GUT energy scale, the lepton mass matrices

S. A. Kulagin

Nuclear effects and QCD perturbative corrections to the Paschos-Wolfenstein relationship are discussed. We argue that perturbative corrections largely cancel out in this relationship for total cross sections while the neutron excess correction in heavy nuclei is enhanced by Fermi motion and nuclear binding effects. These observations are discussed in the con

V. P. Gusynin, V. A. Miransky, I. A. Shovkovy

The linear $SU(2)_L \times SU(2)_R$ sigma-model occupies a unique place in elementary particle physics and quantum field theory. It has been recently realized that when a chemical potential for hypercharge is added, it becomes a toy model for the description of the dynamics of the kaon condensate in high density QCD. We review recent results in nonperturbati

V. A. Bednyakov, and F. Simkovic

We review the calculation of spin-dependent matrix elements relevant to scattering of weakly interacting massive particles on nuclei. A comprehensive list, to our knowledge, of the proton and neutron total spin expectation values ($<{\bf S}_{p}>$ and $<{\bf S}_{n}>$) calculated within different nuclear models is presented. These values allow a conclusion abo

C. S. Kim, Taekoon Lee, Guo-Li Wang

Employing the heavy quark pole mass and static potential that were obtained from resummation of the renormalon-caused large order behavior to all orders, and matching the resummed static potential to the long distance Cornell potential we obtain a new estimate of the bottom quark mass % $m_b^{\bar{\text % MS}}=4.20$ GeV at $α_s(M_z)=0.118$ from $Υ$(1S) syste

Fabien Buisseret, Claude Semay

It is possible to eliminate exactly all the auxiliary fields (einbein fields) appearing in the rotating string Hamiltonian to obtain the classical equations of motion of the relativistic flux tube model. A clear interpretation can then be done for the characteristic variables of the rotating string model.

C. P. Burgess

This article summarizes the proposal to address the cosmological constant problem within the framework of supersymmetric large extra dimensions (SLED). The proposed mechanism is described, emphasizing the relaxation mechanism which ensures that low-energy particles like the electron do not contribute too large a vacuum energy. This is followed by a prelimina

Makoto Oka

A review is given of the theoretical ideas concerning the mysterious pentaquark baryons proposed during the first year after its discovery. We focus on the difficulties involved with the constituent quark models and the discrepancy between the QCD predictions and most of the phenomenological models.

Zhao Zhang, Wei-Qin Zhao

The mixed quark-gluon condensate is another chiral order parameter in QCD, which plays an important role in the application of QCD sum rules. In this letter, we study the properties of quark-gluon mixed condensate at finite temperature and quark chemical potential in the framework of global color symmetry model. Using an infrared-dominant model gluon two-poi

I. P. Lokhtin, A. M. Snigirev

The method for simulation of medium-induced rescattering and energy loss of hard partons in ultrarelativistic heavy ion collisions is developed. The model is realized as fast Monte-Carlo tool implemented to modify standard PYTHIA jet event.

I. P. Lokhtin, A. M. Snigirev

The simple method for simulation of ``thermal&#39;&#39; hadron spectra in ultrarelativistic heavy ion collisions including longitudinal, transverse and elliptic flow is developed. The model is realized as fast Monte-Carlo event generator.

Florian Heinemann

One of the main physics goals of the Large Hadron Collider is the search of particles predicted by supersymmetric theories. This study analyses the possibility of using kinematic endpoints of mass spectra for a sparticle mass reconstruction. It focuses on cascade decays, which include the second-lightest neutralino, in the mSUGRA framework with tan(b) = 35,

Takanobu Ishii

The disappearance of nu_mu was studied using the K2K-I dataset, which was taken before July, 2001. We observed indications of neutrino oscillation. The resultant oscillation-parameter region was consistent with the atmospheric neutrino result. The appearance of nu_e was searced for in the same dataset. No excess was found over the expected background.

Jacek Jezierski

New geometric objects on null thin layers are introduced and their importance for crossing null-like shells are discussed. The Barrabès--Israel equations are represented in a new geometric form and they split into decoupled system of equations for two different geometric objects: tensor density ${\bf G}^a{_b}$ and vector field $I$. Continuity properties of t

G. S. Hall, D. P. Lonie

It is shown using a space-time curvature classification and decomposition that for certain holonomy types of a space-time, proper projective vector fields cannot exist. Existence is confirmed, by example, for the remaining holonomy types. In all except the most general holonomy type, a local uniqueness theorem for proper projective symmetry is established.

S. Kozyrev

A new approach to the model of the universe based on work by Rippl, Romero, Tavakol is presented. We have used the scheme for relating the vacuum (D + 1) dimensional theories to D dimensional theories for setting up a correspondence between vacuum 4-dimensional Einstein theory with 3-dimensional gravity theory with temporal scalar field. These ideas we conti

A. Segui

The measured values of the matter energy density and the vacuum energy density are obtained using an adiabatic black hole percolating model at the critical point. The percolation of black holes is related with an expanding isotropic universe filled with the most entropic fluid saturating the holographic bound.

Vladan Vuckovic, Djordje Vidanovic

We will try to tackle both the theoretical and practical aspects of a very important problem in chess programming as stated in the title of this article - the issue of draw detection by move repetition. The standard approach that has so far been employed in most chess programs is based on utilising positional matrices in original and compressed format as wel

Rajgopal Kannan, Lydia Ray, Arjan Durresi, S. Iyengar

Key predistribution is a well-known technique for ensuring secure communication via encryption among sensors deployed in an ad-hoc manner to form a sensor network. In this paper, we propose a novel 2-Phase technique for key predistribution based on a combination of inherited and random key assignments from the given key pool to individual sensor nodes. We al

Rajgopal Kannan

The Benes network has been used as a rearrangeable network for over 40 years, yet the uniform $N(2 \log N-1)$ control complexity of the $N \times N$ Benes is not optimal for many permutations. In this paper, we present a novel $O(\log N)$ depth rearrangeable network called KR-Benes that is {\it permutation-specific control-optimal}. The KR-Benes routes {\it

Ali Javey, Jing Guo, Damon B. Farmer, Qian Wang

Carbon nanotube field-effect transistors with structures and properties near the scaling limit with short (down to 50 nm) channels, self aligned geometries, palladium electrodes with low contact resistance and high-k dielectric gate insulators are realized. Electrical transport in these miniature transistors is near ballistic up to high biases at both room a

Kazumi Maki, Stephan Haas, David Parker, Hyekyung Won

There is mounting evidence for triplet superconductivity in the recently discovered skutterudite compound PrOs_4Sb_12. In this work, we propose nodal order parameters for the A- and B-phases of this superconductor which are consistent with angle dependent magnetothermal conductivity measurements and with low-temperature thermal conductivity data in the range

K. McElroy, D. -H. Lee, J. E. Hoffman, K. M Lang

Microscopy (STM). At all dopings, the low energy density-of-states modulations are analyzed according to a simple model of quasiparticle interference and found to be consistent with Fermi-arc superconductivity. The superconducting coherence-peaks, ubiquitous in near-optimal tunneling spectra, are destroyed with strong underdoping and a new spectral type appe

Yoichi Tanaka, Norio Kawakami

We investigate spin-polarized transport phenomena through double quantum dots coupled to ferromagnetic leads in series. By means of the slave-boson mean-field approximation, we calculate the conductance in the Kondo regime for two different configurations of the leads: spin-polarization of two ferromagnetic leads is parallel or anti-parallel. It is found tha

M. I. Katsnelson, A. I. Lichtenstein

Starting from exact expression for the dynamical spin susceptibility in the time-dependent density functional theory a controversial issue about exchange interaction parameters and spin-wave excitation spectra of itinerant electron ferromagnets is reconsidered. It is shown that the original expressions for exchange integrals based on the magnetic force theor

V. Yu. Irkhin, M. I. Katsnelson, A. I. Lichtenstein

Anomalous magnetic and electronic properties of the half-metallic ferromagnets (HMF) have been discussed. The general conception of the HMF electronic structure which take into account the most important correlation effects from electron-magnon interactions, in particular, the spin-polaron effects, is presented. Special attention is paid to the so called non

Neil Smith

This article reviews basic theoretical features of Gilbert magnetization dynamics of a single domain magnetic film in the presence of Slonczewski spin-transfer torques, with and without thermal fluctuations taken into account. Rather than showing results of detailed numerical calculations, the discussion here is restricted to basic analytical results and con

H. Schmaljohann, M. Erhard, J. Kronjäger, K. Sengstock

We discuss magnetism in spinor quantum gases theoretically and experimentally with emphasis on temporal dynamics of the spinor order parameter in the presence of an external magnetic field. In a simple coupled Gross-Pitaevskii picture we observe a dramatic suppression of spin dynamics due to quadratic Zeeman &#39;&#39;dephasing&#39;&#39;. In view of an inhom

Dmitry A. Bagrets

We evaluate the full current statistics (FCS) in the low dimensional (1D and 2D) diffusive conductors in the incoherent regime, $eV\gg E_{\rm Th}=D/L^2$, $E_{\rm Th}$ being the Thouless energy. It is shown that Coulomb interaction substantially enhances the probability of big current fluctuations for short conductors with $E_{\rm Th}\gg1/τ_E$, $τ_E$ being th

S. Eriksson, F. Ramirez-Martinez, E. A. Curtis, B. E. Sauer

We have produced magnetic patterns suitable for trapping and manipulating neutral atoms on a $1 μ$m length scale. The required patterns are made in Co/Pt thin films on a silicon substrate, using the heat from a focussed laser beam to induce controlled domain reversal. In this way we draw lines and &#34;paint&#34; shaped areas of reversed magnetization with s

H. Chamati, D. Danchev

We present exact results on the behavior of the thermodynamic Casimir force and the excess free energy in the framework of the $d$-dimensional spherical model with a power law long-range interaction decaying at large distances $r$ as $r^{-d-σ}$, where $σ<d<2σ$ and $0<σ\leq2$. For a film geometry and under periodic boundary conditions we consider the behavior

Mika A. Sillanpää, Leif Roschier, Pertti J. Hakonen

Using a classical equation of motion, dynamics of the phase is analyzed in the Inductive Single-Electron Transistor (L-SET) which is a promising new system suitable for quantum measurement with ultimate sensitivity and low back-action. In a regime of nonlinear dynamics, a shift of the oscillator resonant frequency is discovered which has a direct analogy to

Changxue Deng, Xuedong Hu

Recently an ensemble of nuclear spins in a quantum dot have been proposed as a long-lived quantum memory. A quantum state of an electron spin in the dot can be faithfully transfered into nuclear spins through controlled hyperfine coupling. Here we study the decoherence of this memory due to nuclear spin dipolar coupling and inhomogeneous hyperfine interactio

Luigi Lazzeri, Maria Grazia Cascone, Piero Narducci, Nicola Vitiello

Atomic Force Microscopy (AFM) has become established as a powerful and a versatile tool for investigating local mechanical properties. In addition, it has been made possible to take advantage of the AFM tip-sample interaction, to perturb, and I turn, to modify the surface of soft samples, such as polymers. The accurate knowledge of their response to the cont

N. L. Smith, W. H. Heathcote, J. M. Krueger, C. J. Foot

We have measured the precession frequency of a vortex lattice in a Bose-Einstein condensate of 87Rb atoms. The observed mode corresponds to a collective motion in which all the vortices in the array are tilted by a small angle with respect to the z-axis (the symmetry axis of the trapping potential) and synchronously rotate about this axis. This motion corres

Emmanuel Pereira, Ricardo Falcao

We consider a d-dimensional crystal with an arbitrary harmonic interaction and an anharmonic on-site potential, with stochastic Langevin heat bath at each site. We develop an integral formalism for the correlation functions that is suitable for the study of their relaxation (time decay) as well as their behavior in space. Furthermore, in a perturbative analy

Masatsugu Suzuki, Itsuko S. Suzuki

Aging dynamics of a reentrant ferromagnet Cu$_{0.2}$Co$_{0.8}$Cl$_{2}$-FeCl$_{3}$ graphite bi-intercalation compound has been studied using AC and DC magnetic susceptibility. This compound undergoes successive transitions at the transition temperatures $T_{c}$ ($= 9.7$ K) and $T_{RSG}$ ($= 3.5$ K). The relaxation rate $S(t)$ exhibits a characteristic peak at

Harald O. Jeschke, Gabriel Kotliar

In this paper we explore the use of an equation of motion decoupling method as an impurity solver to be used in conjunction with the dynamical mean field self-consistency condition for the solution of lattice models. We benchmark the impurity solver against exact diagonalization, and apply the method to study the infinite $U$ Hubbard model, the periodic Ande

Michael Budde, Klaus Mølmer

We compute the spatial population statistics for one-dimensional fermi-gases and for bose-gases with hard core repulsions in periodic potentials. We show how the statistics depend on the atomic density in the ground state of the system, and we present calculations for the dynamical turn-on of the potential.

Pawel Jakubczyk Marek Napiorkowski

Within the effective interfacial Hamiltonian approach we evaluate the excess line free energy associated with cylinder-shaped droplets sessile on a stripe-like chemical inhomogeneity of a planar substrate. In the case of short-range intermolecular forces the droplet morphology and the corresponding expression for the line tension - which includes the inhomog

J. J. Garcia-Ripoll, J. I. Cirac

We study the internal dynamics of bosonic atoms in an optical lattice. Within the regime in which the atomic crystal is a Mott insulator with one atom per well, the atoms behave as localized spins which interact according to some spin Hamiltonian. The type of Hamiltonian (Heisenberg, Ising), and the sign of interactions may be tuned by changing the propertie

Alessia Annibale, Giulia Gualdi, Andrea Cavagna

The structure of states of the perturbed p-spin spherical spin-glass is analyzed. At low enough free energy metastable states have a supersymmetric structure, while at higher free energies the supersymmetry is broken. The transition between the supersymmetric and the supersymmetry-breaking phase is triggered by a change in the stability of states.

Thomas Vilmin, Caroline Tadivat, Liliane Leger, Hugh Brown

We study the adhesion between a cross-linked elastomer and a flat solid surface where polymer chains have been end-grafted. To understand the adhesive feature of such a system, one has to study both the origin of the grafted layer interdigitation with the network, and the end-grafted chains extraction out of the elastomer when it comes unstuck from the solid

Malgorzata Wierzbowska, Daniel Sanchez-Portal, Stefano Sanvito

The mechanism for the ferromagnetic order of (Ga,Mn)As and (Ga,Mn)N is extensively studied over a vast range of Mn concentrations. We calculate the electronic structures of these materials using density functional theory in both the local spin density approximation and the LDA+U scheme, that we have now implemented in the code SIESTA. For (Ga,Mn)As, the LDA+

Yukitoshi Motome, Nobuo Furukawa, Naoto Nagaosa

We theoretically explore the mechanism of the colossal magnetoresistance in manganese oxides by explicitly taking into account the phase competition between the double-exchange ferromagnetism and the charge-ordered insulator. We find that quenched disorder causes a drastic change of the multicritical phase diagram by destroying the charge-ordered state selec

Yukitoshi Motome, Hirokazu Tsunetsugu

We present our theoretical results on the mechanism of two transitions in vanadium spinel oxides $A$V$_2$O$_4$ ($A$=Zn, Mg, or Cd) in which magnetic V cations constitute a geometrically-frustrated pyrochlore structure. We have derived an effective spin-orbital-lattice coupled model in the strong correlation limit of the multiorbital Hubbard model, and applie

Fan Yang, Su-peng Kou

In this paper, it is shown how a single stripe and a stripe phase grow from individual holes in low doping regime. In an effective low-energy description of the t-J model, {\em i.e.,} the phase string model, a hole doped into the spin ordered phase will induce a dipolar distortion in the background [Phys. Rev. B{\bf 67}, 115103 (2003)]. We analyze the hole-d

Takao Furubayashi, Hiroyuki Suzuki, Nami Kobayashi, Shoichi Nagata

We report on large negative magnetoresistance observed in ferromagnetic thiospinel compound CuCrZrS$_{4}$. Electrical resistivity increased with decreasing temperature according to the form proportional to $\textrm{exp}(T_{0}/T)^{1/2} $, derived from variable range hopping with strong electron-electron interaction. Resistivity under magnetic fields was expre

N. I. Cade, R. Roshan, M. Hauert, A. C. Maciel

Carrier relaxation processes have been investigated in GaAs/AlGaAs v-groove quantum wires (QWRs) with a large subband separation (46 meV). Signatures of inhibited carrier relaxation mechanisms are seen in temperature-dependent photoluminescence (PL) and photoluminescence-excitation (PLE) measurements; we observe strong emission from the first excited state o

Yongqing Li, Cong Ren, Peng Xiong, Stephan von Molnar

We present a systematic characterization of fluctuations in submicron Hall devices based on GaAs/AlGaAs two-dimensional electron gas heterostructures at temperatures between 1.5 K to 60 K. A large variety of noise spectra, from 1/f to Lorentzian, are obtained by gating the Hall devices. The noise level can be reduced by up to several orders of magnitude with

F. Verstraete, J. J. Garcia-Ripoll, J. I. Cirac

We show how to simulate numerically both the evolution of 1D quantum systems under dissipation as well as in thermal equilibrium. The method applies to both finite and inhomogeneous systems and it is based on two ideas: (a) a representation for density operators which extends that of matrix product states to mixed states; (b) an algorithm to approximate the

S. V. Ghaisas

Growth of interfaces during vapor deposition are analyzed on a discrete lattice. Foe a rough surface, relation between the roughness exponent alpha, and corresponding step-step (slope-slope) couplings is obtained in (1+1) and (2+1) dimensions. From the discrete form and the symmetries of the growth problem, the step -step couplings can be determined. Thus al

Franck Delahaye, Sultana N. Nahar, Anil K Pradhan, Hong Lin Zhang

We investigate the effect of resonances in photoionization and recombination cross sections computed using the R-matrix method. Photoionization and recombination rates derived from high-resolution cross sections for oxygen ions are compared with earlier works with less resolution and accuracy, such as in the widely used Opacity Project data. We find signific

S. G. Korzennik

I describe and present the results of a newly developed fitting methodology optimized for very long time series. The development of this new methodology was motivated by the fact that we now have more than half a decade of nearly uninterrupted observations by GONG and MDI, with fill factors as high as 89.8% and 82.2% respectively. It was recently prompted by

Asantha Cooray

We discuss the stochastic background of gravitational waves from ultra compact neutron star-white dwarf (NS-WD) binaries at cosmological distances. Under the assumption that accreting neutron stars and donor white dwarf stars form most of the low mass X-ray binaries (LMXBs), our calculation makes use of recent results related to the luminosity function deter

G. S. Bisnovatyi-Kogan

Accretion disks are observed in young stars, cataclysmic variables, binary X-ray sources et al. Accretion disk theory was first developed as a theory with the local heat balance, where the whole energy produced by a viscous heating was emitted to the sides of the disk. Important part of this theory was the phenomenological treatment of the turbulent viscosit

Seth Redfield, Jeffrey L. Linsky

We present 50 individual measurements of the gas temperature and turbulent velocity in the local interstellar medium (LISM) within 100 pc. By comparing the absorption line widths of many ions with different atomic masses, we can satisfactorily discriminate between the two dominant broadening mechanisms, thermal broadening, and macroscopic nonthermal, or turb

Jaesub Hong, Eric M. Schlegel, Jonathan E. Grindlay

We present a new technique called &#34;quantile analysis&#34; to classify spectral properties of X-ray sources with limited statistics. The quantile analysis is superior to the conventional approaches such as X-ray hardness ratio or X-ray color analysis to study relatively faint sources or to investigate a certain phase or state of a source in detail, where

Robin Ciardullo, Patrick R. Durrell, Mary Beth Laychak, Kimberly A. Herrmann

We report the results of a photometric and spectroscopic survey for planetary nebulae (PNe) in the Local Group spiral galaxy M33. We use our sample of 152 PNe to derive an [O III] planetary nebula luminosity function (PNLF) distance of (m-M)_0 = 24.86^+0.07-0.11 (0.94^+0.03-0.05 Mpc). Although this value is ~ 15% larger than the galaxy&#39;s Cepheid distance

P. M. Koch, Ph. Jetzer

Recent observations reveal detailed structures of mergers in galaxy clusters. Moving cold fronts could be identified as remnants of subclusters. They are believed to mark the late stage of a merging process. Dynamics, geometry and extension of the subclusters can be very different: Spherically shaped bodies with a radius of $\approx 20 kpc$ up to $\approx 40

Norbert Przybilla, Keith Butler

We investigate the synthesis of the Balmer and Paschen lines of the quiet Sun, using both classical semi-empirical and theoretical model atmospheres, modern line broadening theory and non-LTE line-formation. The computations alleviate long-standing discrepancies between LTE predictions and the observed lines. Theoretical and semi-empirical model atmospheres

Norbert Przybilla, Keith Butler

We discuss aspects of non-LTE line formation for hydrogen in early-type stars. We evaluate the effect of variations in the electron-impact excitation cross sections in model atoms of differing complexity by comparison with observation. While the Balmer lines are basically unaffected by the choice of atomic data, the Paschen, Brackett and Pfund series members

R. -D. Scholz, I. Lehmann, I. Matute, H. Zinnecker

We report the discovery of seven high proper motion stars with proper motions between about 0.7 and 2.2 arcsec/yr. They were detected in an archival search using multi-epoch positions in the optical SuperCOSMOS Sky Surveys and in the near-infrared sky surveys 2MASS and DENIS. The star with the largest proper motion, is spectroscopically classified as a very

J. Kaluzny, A. Olech, I. B. Thompson, W. Pych

We present results of a photometric survey for variable stars in the field of the globular cluster Omega Centauri. The observed region was centered roughly on the cluster core and covered 644 arcmin^2. The cluster was monitored on 59 nights in 1999 and 2000. A total of 117 new variables were identified. Among them there are 16 RR Lyr-type stars, 35 SX Phe va

Peng Wang, Xin-He Meng

We review the Palatini formulation of the higher-derivative gravity of the $L(R)$ form and its applications in cosmology.

G. De Lucia, B. M. Poggianti, A. Aragon-Salamanca, D. Clowe

We study the rest-frame (U-V) color-magnitude relation in 4 clusters at redshifts 0.7-0.8, drawn from the ESO Distant Cluster Survey. We confirm that red-sequence galaxies in these clusters can be described as an old, passively-evolving population and we demonstrate, by comparison with the Coma cluster, that there has been significant evolution in the stella

D. P. K. Banerjee, N. M. Ashok, O. Launila, C. J. Davis

We have searched for the important radioactive isotope 26Al in the nova-like source V4332 Sgr. Recent results from gamma ray astronomy show that there is pervasive emission of the 1.809 MeV gamma ray photon, arising from the decay of 26Al to 26Mg, from all over the galactic plane. Though the sites from where this emission originates are not clearly establish

D. P. K. Banerjee, N. M. Ashok

We present optical observations of the enigmatic nova-like variable V4332 Sgr. The importance of this object should not be understated since it is considered to be the possible prototype of a new class of eruptive variables. These objects have been the subject of considerable studies at present primarily because of the spectacular eruption of V838 Mon - anot

Biman B. Nath

Recent observations of entropy of intracluster medium (ICM) at high redshift are not consistent with a redshift independent entropy floor. In order to interpret these observations, we study models in which the entropy of ICM is enhanced at the epoch of cluster formation (z_f), which then passively evolves as a result of radiative cooling until the epoch of o

Bon-Chul Koo, Ji-hyun Kang, N. M. McClure-Griffiths

We have searched for HI 21 cm line emission from shocked atomic gas associated with southern supernova remnants (SNRs) using data from the Southern Galactic Plane Survey. Among the 97 sources studied, we have detected 10 SNRs with high-velocity HI emission confined to the SNR. The large velocity and the spatial confinement suggest that the emission is likely

Y. Okada, H. Niko, M. Kokubun, K. Makishima

We present an INTEGRAL observation of the Cen-Crux region in order to search the electron cyclotron resonance scattering features from the X-ray binary pulsars. During the AO1 200ks observation, we clearly detected 4 bright X-ray binaries, 1 Seyfert Galaxy, and 4 new sources in the field of view. Especially from GX301-2, the cyclotron resonance feature is de

R. Arnaldi

In this paper we present the preliminary results obtained by the NA60 experiment in Indium-Indium collisions at 158 GeV.

D. I. Golosov

We investigate the zero-temperature phase diagram and spin-wave properties of a double exchange magnet with on-site Hubbard repulsion. It is shown that even within a simple Hartree -- Fock approach this interaction (which is often omitted in theoretical treatments) leads to qualitatively important effects which are highly relevant in the context of experimen

Yair Kurzweil, Roi Baer

Most present applications of time-dependent density functional theory use adiabatic functionals, i.e. the effective potential at time t is determined solely by the density at the same time. This paper discusses a method that aims to go beyond this approximation, by incorporating &#34;memory&#34; effects: the potential will depend also on the history. We add

Aranyabhuti Bhattacherjee

We calculate the absorption spectrum of cold three level Helium atoms in lambda configuration in an optical lattice.Our results show the possibilty of lasing at certain points on the optical lattice which are capable of rendering one of the transitions metastable as compared to the other. A coherent control over the stimulated emission is possible using an a