September 2006 arXiv papers — page 7

Matthew Wingate

Trapped and cooled gases of alkali atoms can be manipulated to exhibit a variety of interesting phenomena. For example, dilute gases of fermionic atoms, in 2 hyperfine states, can be cooled to temperatures where they become superfluid. An external field can be applied to tune the scattering length a. When |a| exceeds the interparticle spacing, nonperturbativ

M. N. Chernodub, S. M. Morozov

We study the embedded QCD monopoles (``quark monopoles'') using low-lying eigenmodes of the overlap Dirac operator in zero- and finite-temperature SU(2) Yang-Mills theory on the lattice. These monopoles correspond to the gauge-invariant hedgehogs in the quark-antiquark condensates. The monopoles were suggested to be agents of the chiral symmetry rest

D0 Collaboration, V. Abazov

We present a measurement of the top quark mass with the Matrix Element method in the lepton+jets final state. As the energy scale for calorimeter jets represents the dominant source of systematic uncertainty, the Matrix Element likelihood is extended by an additional parameter, which is defined as a global multiplicative factor applied to the standard energy

Achim Kempf, Larissa Lorenz

Within the inflationary scenario, Planck scale physics should have affected the comoving modes' initial conditions and early evolution, thereby potentially affecting the inflationary predictions for the cosmic microwave background (CMB). This issue has been studied extensively on the basis of various models for how quantum field theory (QFT) is modified

Ying Zhu, Taikun Cheng, Krishnamoorthy Sivakumar, Benjamin J. Belzer

We present a novel iterative algorithm for detection of binary Markov random fields (MRFs) corrupted by two-dimensional (2D) intersymbol interference (ISI) and additive white Gaussian noise (AWGN). We assume a first-order binary MRF as a simple model for correlated images. We assume a 2D digital storage channel, where the MRF is interleaved before being writ

Pavel Dmitriev, Carl Lagoze

There has been a lot of recent interest in mining patterns from graphs. Often, the exact structure of the patterns of interest is not known. This happens, for example, when molecular structures are mined to discover fragments useful as features in chemical compound classification task, or when web sites are mined to discover sets of web pages representing lo

Jean-Philippe Georges, Nikolai Vatanski, Eric Rondeau, Sirkka-Liisa Jämsä Jounela

Recent interest in networked control systems (NCS) has instigated research in various areas of both communication networks and control. The analysis of NCS has often been performed either from the network, or the control point of view and not many papers exist were the analysis of both is done in the same context. Here a simple overall analysis is presented.

Nikolai Vatanski, Jean-Philippe Georges, Christophe Aubrun, Eric Rondeau

Recent interest in networked control systems (NCS) has instigated research in both communication networks and control. Analysis of NCSs has usually been performed from either the network or the control point of view, but not many papers exist where the analysis of both is done in the same context. In this paper an overall analysis of the networked control sy

Belynda Brahimi, Christophe Aubrun, Eric Rondeau

The objective of this paper is to propose models enabling to study the behaviour of Ethernet switch for Networked Control Systems. Two scheduler policies are analyzed: the static priority and the WRR (Weighted Round Robin). The modelling work is based on Coloured Petri Nets. A temporal validation step based on the simulation of these modelling, shows that th

Qing Zhao, Brian M. Sadler

In this article, we first provide a taxonomy of dynamic spectrum access. We then focus on opportunistic spectrum access, the overlay approach under the hierarchical access model of dynamic spectrum access. we aim to provide an overview of challenges and recent developments in both technological and regulatory aspects of opportunistic spectrum access.

Roxana Smarandache, Ali E. Pusane, Pascal O. Vontobel, Daniel J. Costello

Message-passing iterative decoders for low-density parity-check (LDPC) block codes are known to be subject to decoding failures due to so-called pseudo-codewords. These failures can cause the large signal-to-noise ratio performance of message-passing iterative decoding to be worse than that predicted by the maximum-likelihood decoding union bound. In this pa

Mirela Damian, Robin Flatland, Joseph O'Rourke

An edge-unfolding of a polyhedron is produced by cutting along edges and flattening the faces to a *net*, a connected planar piece with no overlaps. A *grid unfolding* allows additional cuts along grid edges induced by coordinate planes passing through every vertex. A vertex-unfolding permits faces in the net to be connected at single vertices, not necessari

G. Oshanin, R. Voituriez, S. Nechaev, O. Vasilyev

We survey recent results on some one- and two-dimensional patterns generated by random permutations of natural numbers. In the first part, we discuss properties of random walks, evolving on a one-dimensional regular lattice in discrete time $n$, whose moves to the right or to the left are induced by the rise-and-descent sequence associated with a given rando

P. B. Chakraborty, P. J. H. Denteneer, R. T. Scalettar

In this paper we present a determinant quantum monte carlo study of the two dimensional Hubbard model with random site disorder. We show that, as in the case of bond disorder, the system undergoes a transition from an Anderson insulating phase to a metallic phase as the onsite repulsion U is increased beyond a critical value U_c. However, there appears to be

A. B. Harris, Andrea J. Liu

We develop a recursive formula for the probability of a k-cluster in bootstrap percolation.

Alan J. Bray, Satya N. Majumdar

We consider a non-Gaussian stochastic process where a particle diffuses in the $y$-direction, $dy/dt=η(t)$, subject to a transverse shear flow in the $x$-direction, $dx/dt=f(y)$. Absorption with probability $p$ occurs at each crossing of the line $x=0$. We treat the class of models defined by $f(y) = \pm v_{\pm}(\pm y)^α$ where the upper (lower) sign refers

Th. Michael, S. Trimper, J. M. Wesselinowa

A microscopic model for describing ferroelectric nanoparticles is proposed which allows us to calculate the polarization as a function of an external electric field, the temperature, the defect concentration and the particle size. The interaction of the constituents of the material, arranged in layers, depends on both the coupling strength at the surface and

M. V. Milovanovic

We systematically discuss candidate wave functions for the ground state of the bilayer ν= 1 as the distance between the layers is varied. Those that describe increased intralayer correlations at finite distance show a departure from the superflid description for smaller distances. They may support finite energy meron excitations and a dissipative collective

Andreas Roethlein, Florian Baumann, Michel Pleimling

We study the space-time correlation and response functions in nonequilibrium growth processes described by linear stochastic Langevin equations. Exploiting exclusively the existence of space and time dependent symmetries of the noiseless part of these equations, we derive expressions for the universal scaling functions of two-time quantities which are found

Giulio Biroli, Jean-Philippe Bouchaud

We argue that the critical dynamical fluctuations predicted by the mode-coupling theory (MCT) of glasses provide a natural mechanism to explain the breakdown of the Stokes-Einstein relation. This breakdown, observed numerically and experimentally in a region where MCT should hold, is one of the major difficulty of the theory, for which we propose a natural r

Alejandro B. Kolton, Daniel Domínguez

We review our studies of elastic lattices driven by an external force $F$ in the presence of random disorder, which correspond to the case of vortices in superconducting thin films driven by external currents. Above a critical force $F_c$ we find two dynamical phase transitions at $F_p$ and $F_t$, with $F_c<F_p<F_t$. At $F_p$ there is a transition from plast

C. E. Creffield

We study the behavior of a Bose-Einstein condensate held in an optical lattice. We first show how a self-trapping transition can be induced in the system by either increasing the number of atoms occupying a lattice site, or by raising the interaction strength above a critical value. We then investigate how applying a periodic driving potential to the self-tr

C. A. Perroni, H. Ishida, A. Liebsch

Dynamical mean field theory combined with finite-temperature exact diagonalization is shown to be a suitable method to study local Coulomb correlations in realistic multi-band materials. By making use of the sparseness of the impurity Hamiltonian, exact eigenstates can be evaluated for significantly larger clusters than in schemes based on full diagonalizati

T. S. Biro, G. Purcsel

We study the process of equilibration between two non-extensive subsystems in the framework of a particular non-extensive Boltzmann equation. We have found that even subsystems with different non-extensive properties achieve a common equilibrium distribution.

F. Dalla Longa, J. T. Kohlhepp, W. J. M. de Jonge, B. Koopmans

The role of photon angular momentum in laser-induced demagnetization of Nickel thin films is investigated by means of pump-probe time-resolved magneto-optical Kerr effect in the polar geometry. The recorded data display a strong dependency on pump helicity during pump-probe temporal overlap, which is shown to be of non-magnetic origin. By accurately fitting

Thomas Kreibich, Robert van Leeuwen, E. K. U. Gross

We present a general multi-component density functional theory in which electrons and nuclei are treated completely quantum mechanically, without the use of a Born-Oppenheimer approximation. The two fundamental quantities in terms of which our theory is formulated are the nuclear N-body density and the electron density expressed in coordinates referring to t

S. Pittalis, S. Kurth, N. Helbig, E. K. U. Gross

Current-spin density functional theory (CSDFT) provides a framework to describe interacting many-electron systems in a magnetic field which couples to both spin- and orbital-degrees of freedom. Unlike in usual (spin-) density functional theory, approximations to the exchange-correlation energy based on the model of the uniform electron gas face problems in p

Vincent Labiausse, Reinhard Hohler, Sylvie Cohen-Addad

A finite simple shear deformation of an elastic solid induces unequal normal stresses. This nonlinear phenomenon, known as the Poynting effect, is governed by a universal relation between shear strain and first normal stresses difference, valid for non-dissipative elastic materials. We provide the first experimental evidence that an analog of the Poynting ef

Robert van Leeuwen, Nils Erik Dahlen, Adrian Stan

We derive variational expressions for the grand potential or action in terms of the many-body Green function $G$ which describes the propagation of particles and the renormalized four-point vertex $Γ$ which describes the scattering of two particles in many-body systems. The main ingredient of the variational functionals is a term we denote as the $Ξ$-functio

J. Reinisch, A. Heuer

Information about the nature of the low-temperature anomalies and in particular the properties of the tunneling systems in silica and lithium silica glasses are revealed via computer simulations. The potential energy landscape of these systems is systematically explored for adjacent pairs of local minima which may act as double-well potentials (DWP) at low t

C. -H. Pao, S. -T. Wu, S. -K. Yip

We map out the phase diagram of a dilute two-component atomic fermion gas with unequal populations and masses under a Feshbach resonance. As in the case of equal masses, no uniform phase is stable for an intermediate coupling regime. For majority component heavier, the unstable region moves towards the BEC side. When the coupling strength is increased from t

Tobias Kretz, Anna Grünebohm, Maike Kaufman, Florian Mazur

In this work the results of a pedestrian counterflow experiment in a corridor of a width of 2 meter are presented. 67 participants were divided into two groups with varying relative and absolute size and walked in opposite direction through a corridor. The video footage taken from the experiment was evaluated for passing times, walking speeds, fluxes and lan

M. Monteverde, M. Nunez-Regueiro, G. Garbarino, C. Acha

We report that the conductance of macroscopic multiwall nanotube (MWNT) bundles under pressure shows power laws in temperature and voltage, as corresponding to a network of bulk-bulk connected Tomonaga-Luttinger Liquids (LL). Contrary to individual MWNT, where the observed power laws are attributed to Coulomb blockade, the measured ratio for the end and bulk

Anaël Lemaître, Christiane Caroli

We build a mean-field model of plasticity of amorphous solids, based on the dynamics of an ensemble shear transformation zones, interacting via intrinsic dynamical noise generated by the zone flips themselves. We compare the quasi-static, steady-state properties for two types of noise spectrum: (G) Gaussian; (E) broad distribution derived from quadrupolar el

T. Devolder, C. Chappert, J. A. Katine, M. J. Carey

We study the distribution of switching times in spin-transfer switching induced by sub-ns current pulses in pillar-shaped spin-valves. The pulse durations leading to switching follow a comb-like distribution, multiply-peaked at a few most probable, regularly spaced switching durations. These durations reflect the precessional nature of the switching, which o

John Schliemann

We investigate the ballistic motion of electrons and holes in III-V semiconductor quantum wells with spin-orbit coupling and a homogeneous in-plane electric field. As a result of a non-perturbative treatment of both of these influences, particle wave packets undergo a pronounced side jump perpendicular to the field direction. For wave packets of sufficient w

A. Saksaengwijit, A. Heuer

The oxygen and silicon dynamics in silica is compared via computer simulations. In agreement with experimental data and previous simulations a decoupling of oxygen and silicon dynamics is observed upon cooling. The origin of this decoupling is studied in the framework of the potential energy landscape. From analysis of the transition features between neighbo

D. Witthaut, E. M. Graefe, S. Wimberger, H. J. Korsch

We study the properties of coupled linear and nonlinear resonances. The fundamental phenomena and the level crossing scenarios are introduced for a nonlinear two-level system with one decaying state, describing the dynamics of a Bose-Einstein condensate in a mean-field approximation (Gross-Pitaevskii or nonlinear Schroedinger equation). An important applicat

Yu Chuan Wen, Jing Yu Gan, Xiancong Lu, Yue Yu

We study the number statistics of ultracold bosons in optical Lattice using the slave particle technique and quantum Monte Carlo simulations. For homogeneous Bose-Hubbard model, we use the slave particle technique to obtain the number statistics near the superfluid to normal-liquid phase transition. The qualitatively behavior agree with the recent experiment

Katsuyoshi Matsushita, Ryoko Sugano, Akiyoshi Kuroda, Yusuke Tomita

We investigate freezing characteristics of a finite dipolar hexagonal plate by the Monte Carlo simulation. The hexagonal plate is cut out from a piled triangular lattice of three layers with FCC-like (ABCABC) stacking structure. In the present study an annealing simulation is performed for the dipolar plate uniaxially compressed in the direction of layer-pil

Weizhu Bao, Hanquan Wang

In this paper, we propose an efficient and spectrally accurate numerical method for computing the dynamics of rotating Bose-Einstein condensates (BEC) in two dimensions (2D) and 3D based on the Gross-Pitaevskii equation (GPE) with an angular momentum rotation term. By applying a time-splitting technique for decoupling the nonlinearity and properly using the

Jacob D. Stevenson, Peter G. Wolynes

We compare a recent excitation chain argument for the glass transition with the earlier random first order transition theory. The key equation determining the activation barriers and size of cooperatively rearranging regions has the same scaling form in both approaches. The random first order transition theory unambiguously predicts the coefficients in the e

Mario Silveirinha, Nader Engheta

In this work, we study the electrodynamics of metamaterials that consist of resonant non-magnetic inclusions embedded in an epsilon-near-zero (ENZ) host medium. It is shown that the inclusions can be designed in such a way that both the effective permittivity and permeability of the composite structure are simultaneously zero. Two different metamaterial conf

R. Teodorescu, A. Zabrodin, P. Wiegmann

We show that unstable fingering patterns of two dimensional flows of viscous fluids with open boundary are described by a dispersionless limit of the KdV hierarchy. In this framework, the fingering instability is linked to a known instability leading to regularized shock solutions for nonlinear waves, in dispersive media. The integrable structure of the flow

H. J. Herrmann, J. S. Andrade, V. Schatz, G. Sauermann

We use FLUENT to calculate the wind profile over barchans and transverse dunes. The form of the streamlines of flow separation at the lee side of the dunes is determined for a symmetric barchan dune in three dimensions, and for the height profile of a measured transverse dune field in the Lençóis Maranhenses.

Enno Middelberg, Robert J. Sault, Michael J. Kesteven

We present the design of, and a first analysis of data from, the atmospheric seeing monitor at the Australia Telescope Compact Array (ATCA). The seeing monitor has been operational almost continuously since May 2004 and every 10min delivers a measurement of the atmospheric phase stability at the observatory. Its measurements can be used by observers to help

Tod R. Lauer, Karl Gebhardt, S. M. Faber, Douglas Richstone

We combine the results from several HST investigations of the central structure of early-type galaxies to generate a large sample of parameterized surface photometry. The studies included were those that used the &#34;Nuker law&#34; to characterize the inner light distributions of the galaxies. The sample comprises WFPC1 and WFPC2 V band observations publish

Nancy Remage Evans, Gail Schaefer, Howard E. Bond, Edmund Nelan

Polaris, the nearest and brightest classical Cepheid, is a member of at least a triple system. It has a wide ($18&#39;&#39;$) physical companion, the F-type dwarf Polaris B. Polaris itself is a single-lined spectroscopic binary with an orbital period of 30 years (Kamper, 1996, JRASC, 90, 140). By combining {\it Hipparcos} measurements of the instantaneous pr

G. Branduardi-Raymont, A. Bhardwaj, R. F. Elsner, G. R. Gladstone

We present the results of a spectral study of the soft X-ray emission (0.2-2.5 keV) from low-latitude (`disk&#39;) regions of Jupiter. The data were obtained during two observing campaigns with XMM-Newton in April and November 2003. While the level of the emission remained approximately the same between April and the first half of the November observation, t

N. Shaposhnikov, J. Swank, C. R. Shrader, M. Rupen

The black-hole X-ray binary transient GRO J1655-40 underwent an outburst beginning in early 2005. We present the results of our multi-wavelength observational campaign to study the early outburst spectral and temporal evolution, which combines data from X-ray (RXTE, INTEGRAL), radio (VLA) and optical (ROTSE, SMARTS) instruments. During the reported period th

Rosa I. Diaz-Miller

In preparation for James Webb Space Telescope (JWST), a set of cross calibration programs with HST and Spitzer for suitable primary photometric standards and astrometric fields were developed. NICMOS/HST and IRAC/Spitzer photometry observations of new solar analog standards in NGC 6791 and Melotte 66 were executed. These new photometric standards will provid

M. Schrinner, K. -H. Raedler, D. Schmitt, M. Rheinhardt

A comparison is made between mean-field models and direct numerical simulations of rotating magnetoconvection and the geodynamo. The mean-field coefficients are calculated with the fluid velocity taken from the direct numerical simulations. The magnetic fields resulting from mean-field models are then compared with the mean magnetic field from the direct num

Caroline van Breukelen, Lee Clewley, David Bonfield

We present a new cluster-finding algorithm based on a combination of the Voronoi Tessellation and Friends-Of-Friends methods. The algorithm utilises probability distribution functions derived from a photometric redshift analysis. We test our algorithm on a set of simulated cluster-catalogues and have published elsewhere its employment on UKIDSS Ultra Deep Su

J. Rodriguez, G. Pooley, D. C. Hannikainen, H. J. Lehto

We report here the results of 2 observations performed simultaneously with INTEGRAL, RXTE, the Ryle and Nancay radio telescopes. These observations belong to the so-called $ν$ and $λ$ classes of variability during which a high level of correlated X-ray and radio variability is observed. We study the connection between the accretion processes seen in the X-ra

M. Einasto, J. Einasto, E. Tago, E. Saar

We use catalogues of superclusters of galaxies from the 2dF Galaxy Redshift Survey to study the properties of galaxies in superclusters. We compare the properties of galaxies in high and low density regions of rich superclusters, in poor superclusters and in the field, as well as in groups, and of isolated galaxies in superclusters of various richness. We sh

Serena Criscuoli, Mark Rast, Ilaria Ermolli, Mauro Centrone

Several studies have investigated the fractal and multifractal nature of magnetic features in the solar photosphere and its variation with the solar magnetic activity cycle. Here we extend those studies by examining the fractal geometry of bright magnetic features at higher atmospheric levels, specifically in the solar chromosphere. We analyze structures ide

J. I. Davies, M. J. Disney, R. F. Minchin, R. Auld

One explanation for the disparity between Cold Dark Matter (CDM) predictions of galaxy numbers and observations could be that there are numerous dark galaxies in the Universe. These galaxies may still contain baryons, but no stars, and may be detectable in the 21cm line of atomic hydrogen. The results of surveys for such objects, and simulations that do/do n

R. A. N. Smith, M. J. Page, G. Branduardi-Raymont

We present a detailed analysis of the soft X-ray spectrum of the Seyfert 1 galaxy Markarian 509 taken with the XMM-Newton Reflection Grating Spectrometer. An underlying power-law continuum and three warm absorber phases provide a good fit to the data along with a number of broad and narrow emission lines. Our three warm absorber phases each have different io

Y. Xin, L. Deng, Z. Han

Blue straggler stars present as secure members in the Galactic open clusters form a major challenge to the conventional picture of evolutionary population synthesis based on the stellar evolution theory of single stars, as illustrated in our previous work. Expansion of our sample in the current work to include younger age clusters provides a larger data base

A. Lecavelier des Etangs

To describe the evaporation status of the extrasolar planets, we propose to consider an energy diagram in which the potential energy of the planets is plotted versus the energy received by the upper atmosphere. Here we present a basic method to estimate these quantities. For the potential energy, we include the modification of the gravity field by the tidal

R. Wischnewski

The Baikal Neutrino Telescope has been operating in its NT200 configuration since April, 1998. The telescope has been upgraded in April, 2005, to the 10 Mton scale detector NT200+. It&#39;s main physics goal is the detection of signals from high energy neutrino cascades. NT200+ reaches a 3-year sensitivity of 2 \times 10^{-7}cm^{-2}s^{-1}sr^{-1}GeV for an al

S. Geier, S. Nesslinger, U. Heber, N. Przybilla

The nature of the progenitors of type Ia supernovae is still under controversial debate. KPD 1930+2752 is one of the best SN Ia progenitor candidates known today. The object is a double degenerate system consisting of a subluminous B star (sdB) and a massive white dwarf (WD). Maxted et al. (2000) conclude that the system mass exceeds the Chandrasekhar mass.

Marta Volonteri

Massive black holes (MBHs), with masses in the range 10^3-10^8 Msolar, which merge with a companion black hole of similar mass are expected to be the most powerful source of gravitational radiation in the frequency range probed by LISA. MBH binaries can be detected by LISA up to z~5-15. Gravitational waves from MBH mergers can serve as a powerful tool to stu

M. S. Marley, J. J. Fortney, O. Hubickyj, P. Bodenheimer

Traditional thermal evolution models of giant planets employ arbitrary initial conditions selected more for computational expediency than physical accuracy. Since the initial conditions are eventually forgotten by the evolving planet, this approach is valid for mature planets, if not young ones. To explore the evolution at young ages of jovian mass planets w

V. Buat, T. T. Takeuchi, J. Iglesias-Paramo, C. K. Xu

We select far-infrared (FIR-60 microns) and far-ultraviolet (FUV-1530 A) samples of nearby galaxies in order to discuss the biases encountered by monochromatic surveys (FIR or FUV). Very different volumes are sampled by each selection and much care is taken to apply volume corrections to all the analyses. The distributions of the bolometric luminosity of you

G. Tovmassian, S. Zharikov, V. Neustroev

Cataclysmic Variables (CV) are close binary systems, in which the primary, the more massive star, is a white dwarf. CVs usually exhibit a number of periodicities, most of which are now understood. However, recently, a new phenomenon was discovered that does not fit the standard picture. Two objects have been discovered to show periods that are much longer th

Christopher T. Rodgers, Ron Canterna, J. Allyn Smith, Michael J. Pierce

We report improved transformation equations between the $u&#39;g&#39;r&#39;i&#39;z&#39;$ and $UBVR_CI_C$ photometric systems. Although the details of the transformations depend on luminosity class, we find a typical rms scatter on the order of 0.001 magnitude if the sample is limited to main sequence stars. Furthermore, we find an accurate transformation req

M. Tamura, R. Kandori, N. Kusakabe, Y. Nakajima

Wide-field (~8&#39; x 8&#39;) and deep near-infrared (JHKs bands) polarization images of the Orion nebulae (IRNe) around young stellar objects (YSOs), both massive and low-mass. We found the IRNe around both IRc2 and BN to be very extensive, suggesting that there might be two extended (>0.7 pc) bipolar/monopolar IRNe in these sources. We discovered at least

Stuart Wyithe, Avi Loeb

Deep surveys have recently discovered galaxies at the tail end of the epoch of reionization. In the near future, these discoveries will be complemented by a new generation of low-frequency radio observatories that will map the distribution of neutral hydrogen in the intergalactic medium through its redshifted 21cm emission. In this paper we calculate the exp

H. Hirashita, L. K. Hunt

We investigate the radio spectral energy distributions (SEDs) of young star-forming galaxies and how they evolve with time. The duration and luminosity of the nonthermal radio emission from supernova remnants (SNRs) are constrained by using the observational radio SEDs of SBS 0335-052 and I Zw 18, which are the two lowest-metallicity blue compact dwarf galax

Ian J. Parrish, James M. Stone

In many magnetized, dilute astrophysical plasmas, thermal conduction occurs almost exclusively parallel to magnetic field lines. In this case, the usual stability criterion for convective stability, the Schwarzschild criterion, which depends on entropy gradients, is modified. In the magnetized long mean free path regime, instability occurs for small wavenumb

Tadashi Nakajima, Masahiro Morikawa

Flat density cores have been obtained for a limited number of clusters of galaxies by strong gravitational lensing. This paper explores the possibility that the degeneracy pressure of fermionic dark matter accounts for the flat top density profiles. This is a case study of A1689 for which the density profile has been obtained from the inner region out to 1Mp

L. R. Bellot Rubio

Inversion techniques (ITs) allow us to infer the magnetic, dynamic, and thermal properties of the solar atmosphere from polarization line profiles. In recent years, major progress has come from the application of ITs to state-of-the-art observations. This paper summarizes the main results achieved both in the photosphere and in the chromosphere. It also disc

Alejandro Corichi, Jacobo Diaz-Polo, Enrique Fernandez-Borja

Ever since the pioneer works of Bekenstein and Hawking, black hole entropy has been known to have a quantum origin. Furthermore, it has long been argued by Bekenstein that entropy should be quantized in discrete (equidistant) steps given its identification with horizon area in (semi-)classical general relativity and the properties of area as an adiabatic inv

A. Libal, C. Reichhardt, C. J. Olson Reichhardt

We study the topological configurations and dynamics of individual point defect vacancies and interstitials in a two-dimensional colloidal crystal. Our Brownian dynamics simulations show that the diffusion mechanism for vacancy defects occurs in two phases. The defect can glide along the crystal lattice directions, and it can rotate during an excited topolog

Fred Cooper, Gouranga C. Nayak

We consider expressions of the form of an exponential of the sum of two non-commuting operators of a single variable inside a path integration. We show that it is possible to shift one of the non-commuting operators from the exponential to other functions which are pre-factors and post-factors when the domain of integration of the argument of that function i

Vitaly V. Bulatov, Yuriy V. Vladimirov

The internal gravity waves are the oscillations present in the gravitational field of the stratified medium, that is the mediums which density raises with the depth change. If the equilibrium state of the component volume of this medium is disturbed, for example, upward, then it will become more heavy, than the medium surrounding it, and Archimedian forces w

Penny Smith

This paper is being withdrawn by the author due a serious flaw.

Leon A. Takhtajan, Peter G. Zograf

For moduli space of stable parabolic bundles on a compact Riemann surface, we derive an explicit formula for the curvature of its canonical line bundle with respect to Quillen&#39;s metric and interpret it as a local index theorem for the family of dbar-operators in associated parabolic endomorphism bundles. The formula consists of two terms: one standard (p

J. Nordhaus, E. G. Blackman, A. Frank

The origin, evolution and role of magnetic fields in the production and shaping of proto-planetary and planetary nebulae (PPNe, PNe) is a subject of active research. Most PNe and PPNe are axisymmetric with many exhibiting highly collimated outflows, however, it is important to understand whether such structures can be generated by isolated stars or require t

Peter C. Richter

Most approximation algorithms for #P-complete problems (e.g., evaluating the permanent of a matrix or the volume of a polytope) work by reduction to the problem of approximate sampling from a distribution $π$ over a large set $§$. This problem is solved using the {\em Markov chain Monte Carlo} method: a sparse, reversible Markov chain $P$ on $§$ with station

Steven N. Evans, David Steinsaltz, Kenneth W. Wachter

We investigate a continuous time, probability measure-valued dynamical system that describes the process of mutation-selection balance in a context where the population is infinite, there may be infinitely many loci, and there are weak assumptions on selective costs. Our model arises when we incorporate very general recombination mechanisms into a previous m

I. Minchev, A. Quillen

We perform test-particle simulations in a 2D, differentially rotating stellar disk, subjected to a two-armed steady state spiral density wave perturbation in order to estimate the influence of spiral structure on the local velocity field. By using Levenberg-Marquardt least-squares fit we decompose the local velocity field (as a result of our simulations) int

Mylène Maïda

We establish a large deviation principle for the largest eigenvalue of a rank one deformation of a matrix from the GUE or GOE. As a corollary, we get another proof of the phenomenon, well-known in learning theory and finance, that the largest eigenvalue separates from the bulk if the perturbation is large enough. A large part of the paper is devoted to an au

Alexander Vilenkin

I review recent progress in defining a probability measure in the inflationary multiverse. General requirements for a satisfactory measure are formulated and recent proposals for the measure are clarified and discussed.

J. Fransson, Jian-Xin Zhu

The dynamics of a single spin embedded in the tunnel junction (quantum point contact) between ferromagnets is addressed. Using the Keldysh technique, we derive a quantum Langevin equation. As a consequence of the spin-polarization in the leads, the spin displays a rich and unusual dynamics. Parallel configured and equally strong magnetic moments in the leads

Götz S. Uhrig

A general strategy to maintain the coherence of a quantum bit is proposed. The analytical result is derived rigorously including all memory and back-action effects. It is based on an optimized $π$-pulse sequence for dynamic decoupling extending the Carr-Purcell-Meiboom-Gill (CPMG) cycle. The optimized sequence is very efficient, in particular for strong coup

M. F. Nieva, N. Przybilla

Carbon is one of the most abundant metals in the universe because of its synthesis in the fundamental triple alpha reaction. The knowledge of carbon abundances in different environments is one key ingredient to our understanding of stellar and galactochemical evolution. Studies of luminous OB-type stars allow us to address both topics even in galaxies beyond

Malte Henkel

Recent studies on the phenomenology of ageing in certain many-particle systems which are at a critical point of their non-equilibrium steady-states, are reviewed. Examples include the contact process, the parity-conserving branching-annihilating random walk, two exactly solvable particle-reaction models and kinetic growth models. While the generic scaling de

Richard Atkins

As is well known, a metric on a manifold determines a unique symmetric connection for which the metric is parallel: the Levi-Civita connection. In this paper we investigate the inverse problem: to what extent is the metric of a Riemannian manifold determined by its Levi-Civita connection? It is shown that for a generic Levi-Civita connection of a metric $h$

D. D. Ferrante, G. S. Guralnik

By means of an analogy with Classical Mechanics and Geometrical Optics, we are able to reduce Lagrangians to a kinetic term only. This form enables us to examine the extended solution set of field theories by finding the geodesics of this kinetic term&#39;s metric. This new geometrical standpoint sheds light on some foundational issues of QFT and brings to t

Laurent Baulieu, Guillaume Bossard

Using the shadow dependent decoupled Slavnov-Taylor identities associated to gauge invariance and supersymmetry, we discuss the renormalization of the N=4 super-Yang-Mills theory and of its coupling to gauge-invariant operators. We specify the method for the determination of non-supersymmetric counterterms that are needed to maintain supersymmetry.

Hai Lin

We study instanton solutions and superpotentials for the large number of vacua of the plane-wave matrix model and a 2+1 dimensional Super Yang-Mills theory on $R\times S^2$ with sixteen supercharges. We get the superpotential in the weak coupling limit from the gauge theory description. We study the gravity description of these instantons. Perturbatively wit

Roland Bacher

We study the interpolation group whose elements are suitable pairs of formal power series. This group has a faithful representation into infinite lower triangular matrices and carries thus a natural structure as a Lie group. The matrix exponential between its Lie algebra and its matrix representation gives rise to a function with interesting properties exten

M. Doring, V. Koch

Net-Charge fluctuations in a hadron gas are studied using an effective hadronic interaction. The emphasis of this work is to investigate the corrections of hadronic interactions to the charge fluctuations of a non-interacting resonance gas. Several methods, such as loop, density and virial expansions are employed. The calculations are also extended to SU(3)

David Sherman

In this paper an automorphism of a unital C*-algebra is said to be /locally inner/ if on any element it agrees with some inner automorphism. We make a fairly complete study of local innerness in von Neumann algebras, incorporating comparison with the pointwise innerness of Haagerup-Stormer. On some von Neumann algebras, including all with separable predual,

Ko Honda, William H. Kazez, Gordana Matic

We present an alternate description of the Ozsvath-Szabo contact class in Heegaard Floer homology. Using our contact class, we prove that if a contact structure (M,ξ) has an adapted open book decomposition whose page S is a once-punctured torus, then the monodromy is right-veering if and only if the contact structure is tight.

A. D. Martin, M. G. Ryskin, G. Watt

We analyse the latest H1 large rapidity gap data to obtain diffractive parton distributions, using a procedure based on perturbative QCD, and compare them with distributions obtained from the simplified Regge factorisation type of analysis. The diffractive parton densities and structure functions are made publically available.

Matthias Bornhofen, Urs Hartl

Pure t-motives were introduced by G. Anderson as higher dimensional generalizations of Drinfeld modules, and as the appropriate analogs of abelian varieties in the arithmetic of function fields. In this article we develop their theory regarding morphisms, isogenies, Tate modules, and local shtukas. The later are the analog of p-divisible groups. We investiga

Luc Blanchet

The dynamics of &#34;dipolar particles&#34;, i.e. particles endowed with a four-vector mass dipole moment, is investigated using an action principle in general relativity. The action is a specific functional of the particle&#39;s world line, and of the dipole moment vector, considered as a dynamical variable. The first part of the action is inspired by that