November 2005 arXiv papers — page 3

G. De Cesare, A. Bazzano, G. Stratta, M. Del Santo

KS 1741-293 was firstly detected in 1989 with the X-ray wide field camera TTM (3-10 keV) on board of the Rontgen-Kvant-Mir observatory. During these observations this source exhibited two X-ray bursts allowing to identify it as a neutron star in a Low mass X-ray Binary. During the BeppoSAX/WFC monitoring of the Galactic Centre Region, KS 1741-293 was also re

A. -Y. Zhou, M. D. Reed, S. Harms, D. M. Terndrup

We present the results of extensive time series photometry of the pulsating subdwarf B star KPD 2109+4401. Our data set consists of 29 data runs with a total length of 182.6 hours over 31 days, collected at five observatories in 2004. These data are comprised of high signal-to-noise observations acquired with larger telescopes and wider time coverage observa

Kei Kotake, Naofumi Ohnishi, Shoichi Yamada, Katsuhiko Sato

We report a current status of our radiation-magnetohydrodynamic code for the study of core-collapse supernovae. In this contribution, we discuss the accuracy of our newly developed numerical code by presenting the test problem in a static background model. We also present the application to the spherically symmetric core-collapse simulations. Since close com

Marek J. Sarna, Ene Ergma, Jelena Greskevits

We perform evolutionary calculations of binary stars to find progenitors of systems with parameters similar to the recurrent nova U Sco. We show that a U Sco-type system may be formed starting with an initial binary system which has a low-mass carbon-oxygen white dwarf as an accretor. Since the evolutionary stage of the secondary is not well known, we calcul

M. Mouhcine, R. A. Gonzalez, M. C. Liu

We present new theoretical models for surface brightness fluctuations in the near-infrared. We show the time evolution of near-infrared brightness fluctuation properties over large age and metallicity ranges, i.e., from 12 Myr to 16 Gyr, and from Z/Zsun=1/50 to Z/Zsun=2.5, for single age, single metallicity stellar populations. All the stellar models are fol

Michaela Kraus, Marcelo Borges Fernandes, Diana Andrade Pilling, Francisco X. de Araujo

We report on the detection of [OI] emission lines in the high-resolution optical spectra of several Magellanic Cloud (MC) B[e] supergiants, which we took with FEROS at the ESO 1.52m telescope in La Silla (Chile). In addition, we model the [OI] line luminosities and show that the best location for the neutral oxygen material is the outflowing disk. In order t

Michaela Kraus, Marcelo Borges Fernandes, Francisco X. de Araujo, Henny J. G. L. M. Lamers

We present a study of the optical spectrum of the fascinating B[e] star Hen 2-90 based on new high-resolution observations taken with FEROS at the ESO 1.52m telescope in La Silla (Chile). The recent HST image of Hen 2-90 (Sahai et al. 2002) reveals a bipolar, highly ionized region, a neutral disk-like structure seen almost perfectly edge-on, and an intermedi

Marcelo Borges Fernandes, Silvia Lorenz Martins, Michaela Kraus, Francisco X. de Araujo

(abridged) In this work we present the results of an optical and IR study for the curious B[e] star CD-42 11721. This object has a doubtful evolutionary stage, being either a pre-main sequence star (HAeB[e]) or an evolved star (sgB[e]). Our optical investigation could be splitted in two parts, a qualitative study based on the identification of the numerous e

Gijs Verdoes Kleijn, Tim de Zeeuw

We examine the relative orientations of radio jets, central dust and stars in low-power (i.e., FR I and FR I/II) radio galaxies. We use the position angles of jet and dust to constrain the three-dimensional angle $θ_{\rm DJ}$ between jet and dust. For galaxies with filamentary dust 'lanes' (which tend to be misaligned with the galaxy major axis) the

A. Vale, J. P. Ostriker

We present a non-parametric, empirically based, model for associating galaxy luminosities with halo/subhalo masses, based on a self-consistent treatment of subhalo mass loss and the subhalo mass function. We find that, at high mass, the mass-luminosity relation is almost independent of the actual luminosity function considered, when luminosity is scaled by t

F. A. van Broekhuizen, I. M. N. Groot, H. J. Fraser, E. F. van Dishoeck

The spectra of pure, mixed and layered CO and CO2 ices have been studied systematically under laboratory conditions using infrared spectroscopy. This work provides improved resolution spectra (0.5 cm-1) of the CO2 bending and asymmetric stretching mode, as well as the CO stretching mode, extending the existing Leiden database of laboratory spectra to match t

Alexander Mishev, Strashimir Mavrodiev, Jordan Stamenov

This work summarizes the results presented at 29th International Cosmic Ray Conference in Pune India. Generally the aim of this work is to obtain the lateral distribution of the atmospheric Cherenkov light in extensive air showers produced by different primary particles in wide energy range and at several observation levels and to fit the obtained lateral di

S. V. Marchenko

How much dust can be produced in the early Universe? Does dust production depend on the average heavy-metal content of the hosting galaxy? Considering supernova explosions, massive stars (Wolf-Rayet, LBV and RSG), and relatively massive AGB stars among possible dust-generating objects in the early Universe, we find that SN remnants can be regarded as the mai

Vitaly Vanchurin, Ken D. Olum, Alexander Vilenkin

We study the spectrum of loops as a part of a complete network of cosmic strings in flat spacetime. After a long transient regime, characterized by production of small loops at the scale of the initial conditions, it appears that a true scaling regime takes over. In this final regime the characteristic length of loops scales as $0.1 t$, in contrast to earlie

Joshua L. Davis

We explore the moduli space of heterotic strings in two dimensions. In doing so, we introduce new lines of compactified theories with Spin(24) gauge symmetry and discuss compactifications with Wilson lines. The phase structure of d=2 heterotic string theory is examined by classifying the hypersurfaces in moduli space which support massless quanta or discrete

Rita Sinha, Tarun Souradeep

The recent Cosmic Microwave Background (CMB) measurements indicate that there is power deficiency of the CMB anisotropies at large scales compared with the $Λ$CDM model. We have investigated the possibility of explaining such effects by a class of primordial power spectra which have infrared cutoffs close to the horizon scale. The primordial power spectrum r

Z. Salman, T. J. Parolin, K. H. Chow, T. A. Keeler

We present longitudinal field muon spin relaxation ($μ$SR) measurements in the unilluminated state of the photo-sensitive molecular magnetic Co-Fe Prussian blue analogues M$_{1-2x}$Co$_{1+x}$[Fe(CN)$_6$]$\cdot z$ H$_2$O, where M=K and Rb with $x=0.4$ and $\simeq 0.17$, respectively. These results are compared to those obtained in the $x=0.5$ stoichiometric l

Koji Hashimoto, Seiji Terashima

We completely realize the ADHM construction of instantons in D-brane language of tachyon condensations. Every step of the construction is given a physical interpretation in string theory, in a boundary state formalism valid all order in α'. Accordingly, equivalence between Yang-Mills configurations on D4-branes and D0-branes inside the D4-branes is prove

Daniel Braun

I show that the decoherence in a system of $N$ degenerate two--level atoms interacting with a bosonic heat bath is for any number of atoms $N$ governed by a generalized Hamming distance (called ``decoherence metric'') between the superposed quantum states, with a time--dependent metric tensor that is specific for the heat bath.The decoherence metric

G. Watt

We discuss the perturbative QCD description of diffractive deep-inelastic scattering, and extract diffractive parton distributions from recent HERA data. The asymptotic collinear factorisation theorem has important modifications in the sub-asymptotic HERA regime. In addition to the usual resolved Pomeron contribution, the direct interaction of the Pomeron mu

S. Heinemeyer, S. Kanemura, H. Logan, A. Raspereza

This report reviews the properties of Higgs bosons in the Standard Model (SM) and its various extensions. We give an extensive overview about the potential of the ILC operated at centre-of-mass energies up to 1 TeV (including the gamma gamma option) for the determination of the Higgs boson properties. This comprises the measurement of the Higgs boson mass, i

Keisuke Hasegawa, Charles A. Rohde, Miriam Deutsch

We present a theoretical study of the dispersion relation of surface plasmon resonances of mesoscopic metal-dielectric-metal microspheres. By analyzing the solutions to Maxwell's equations, we obtain a simple geometric condition for which the system exhibits a band of surface plasmon modes whose resonant frequencies are weakly dependent on the multipole

J. Dietel, H. Kleinert

We set up a melting model for vortex lattices in high-temperature superconductors based on the continuum elasticity theory. The model is Gaussian and includes defect fluctuations by means of a discrete-valued vortex gauge field. We derive the melting temperature of the lattice and predict the size of the Lindemann number. Our result agrees well with experime

Yves de Cornulier, Luc Guyot, Wolfgang Pitsch

We investigate the isolated points in the space of finitely generated groups. We give a workable characterization of isolated groups and study their hereditary properties. Various examples of groups are shown to yield isolated groups. We also discuss a connection between isolated groups and solvability of the word problem.

Faisal Mehmood, Abdelkader Kara, Talat S. Rahman, Klaus Peter Bohnen

Our ab initio calculations of CO adsorption on several low and high miller index surfaces of Cu show that the adsorption energy increases as the coordination of the adsorption site decreases from 11 to 6, in qualitative agreement with experimental observations. On each surface the adsorption energy is also found to decrease with increase in coverage, althoug

Bogdan Damski, Wojciech H. Zurek

We show that a simple approximation based on concepts underlying the Kibble-Zurek theory of second order phase transition dynamics can be used to treat avoided level crossing problems. The approach discussed in this paper provides an intuitive insight into quantum dynamics of two level systems, and may serve as a link between the theory of dynamics of classi

Mauro Riccardi

The Quantum Mechanics of a point particle on a Noncommutative Plane in a magnetic field is implemented in the present work as a deformation of the algebra which defines the Landau levels. I show how to define, in this deformed Quantum Mechanics, the physical observables, like the density correlation functions and Green function, on the completely filled grou

Robert Coquereaux

We relate quantum 6J symbols of various types (quantum versions of Wigner and Racah symbols) to Ocneanu cells associated with AN Dynkin diagrams. We check explicitly the algebraic structure of the associated quantum groupoids and analyze several examples (A3, A4). Some features relative to cells associated with more general ADE diagrams are also discussed.

G. Ghirlanda, M. Magliocchetti, G. Ghisellini, L. Guzzo

We cross correlate Gamma--Ray Bursts and X--Ray selected clusters of galaxies at z\leq0.45. We find a positive 2σsignal for the angular cross--correlation function w_{bc}(θ) on scales θ\leq 3 deg between short GRBs and clusters. Conversely, no correlation is found between clusters and the population of long GRBs. The comparison with the cluster autocorrelati

Bert Schroer

This addendum adds some comments to a published paper (B. Schroer, Class. Quantum Grav. 23, (2006) 5227) on area density of localization-entropy. The setting of holography and localization-entropy is generalized to double cones and black holes with bifurcate Killing horizons. PACS: 11.10.-z, 11.25.Hf, 04.70.Dy

Luis Felipe Tabera

The notion of geometric construction is introduced. This notion allows to compare incidence configurations in the algebraic and tropical plane. We provide an algorithm such that, given a tropical instance of a geometric construction, it computes sufficient conditions to have an algebraic counterpart related by tropicalization. We also provide sufficient cond

Martin Schnabl

We propose a new basis in Witten's open string field theory, in which the star product simplifies considerably. For a convenient choice of gauge the classical string field equation of motion yields straightforwardly an exact analytic solution that represents the nonperturbative tachyon vacuum. The solution is given in terms of Bernoulli numbers and the e

Faisal Mehmood, Abdelkader Kara, Talat S. Rahman

Using density functional theory with the generalized gradient approximation and ultra-soft pseudo-potentials, we have calculated structural relaxations of the Cu(532) surface which contains steps and kinks. We find the relaxation pattern to oscillate dramatically for atoms in the first 10 layers before decaying rapidly in the bulk. The most striking feature

Kenneth Pryor

A favorable environment for downbursts associated with deep convective storm systems that occur over the central and eastern continental United States includes strong static instability with large amounts of convective available potential energy and the presence of a mid-tropospheric layer of dry air. However, previous research has identified that over the c

Ben Ibinson, Noah Linden, Andreas Winter

The relative entropy of two n-party quantum states is an important quantity exhibiting, for example, the extent to which the two states are different. The relative entropy of the states formed by reducing two n-party to a smaller number $m$ of parties is always less than or equal to the relative entropy of the two original n-party states. This is the monoton

Alexander Grigoriev, Alexander Studenikin, Alexei Ternov

We consider the matter effects on neutrinos moving in background on the basis of the corresponding quantum wave equations. Both Dirac and Majorana neutrino cases are discussed. The effects for Dirac neutrino reflection and trapping as well as neutrino-antineutrino annihilation and $ν\overlineν$ pair creation in matter at the interface between two media with

Max Tegmark, Anthony Aguirre, Martin J Rees, Frank Wilczek

We identify 31 dimensionless physical constants required by particle physics and cosmology, and emphasize that both microphysical constraints and selection effects might help elucidate their origin. Axion cosmology provides an instructive example, in which these two kinds of arguments must both be taken into account, and work well together. If a Peccei-Quinn

Axel Kleinschmidt, Hermann Nicolai

We construct simple exact solutions to the E10/K(E10) coset model by exploiting its integrability. Using the known correspondences with the bosonic sectors of maximal supergravity theories, these exact solutions translate into exact cosmological solutions. In this way, we are able to recover some recently discovered solutions of M-theory exhibiting phases of

Boris Kruglikov, Valentin Lychagin

We study the equivalence problem of submanifolds with respect to a transitive pseudogroup action. The corresponding differential invariants are determined via formal theory and lead to the notions of k-variants and k-covariants, even in the case of non-integrable pseudogroup. Their calculation is based on the cohomological machinery: We introduce a complex f

Z. Nagy, Z. Trocsanyi

We compute the differential distributions of two three-jet event-shape observables at the next-to-leading order accuracy at fixed values of the DIS kinematic variables. The observable $\Kout$ measures the out-of-event-plane momentum. The other observable $y_3$ is the maximum value of the $\ycut$ resolution variable for which an event is classified as three-j

John C. Baez, Urs Schreiber

Just as gauge theory describes the parallel transport of point particles using connections on bundles, higher gauge theory describes the parallel transport of 1-dimensional objects (e.g. strings) using 2-connections on 2-bundles. A 2-bundle is a categorified version of a bundle: that is, one where the fiber is not a manifold but a category with a suitable sm

Stefano Pirandola

The content of this paper is now available as part of arXiv:0902.1502

Michael Röckner, Zeev Sobol

We develop a new method to uniquely solve a large class of heat equations, so-called Kolmogorov equations in infinitely many variables. The equations are analyzed in spaces of sequentially weakly continuous functions weighted by proper (Lyapunov type) functions. This way for the first time the solutions are constructed everywhere without exceptional sets for

Harald G. Svendsen

This paper discusses global properties of exact (in alpha prime) string theory solutions: A deformed black hole solution in two dimensions and a Taub-NUT type solution in four dimensions. These models are exact by virtue of having CFT descriptions in terms of heterotic coset models. The analysis includes analytic continuations of the metric, motion of test p

Amand Faessler, Th. Gutsche, V. E. Lyubovitskij, K. Pumsa-ard

We develop a manifestly Lorentz covariant chiral quark model for the study of baryons as bound states of constituent quarks dressed by a cloud of pseudoscalar mesons. The approach is based on a non-linear chirally symmetric Lagrangian, which involves effective degrees of freedom - constituent quarks and the chiral (pseudoscalar meson) fields. In a first step

D. Fargion, M. Khlopov, C. A. Stephan

A new candidate of cold dark matter arises by a novel elementary particle model: the almostcommutative AC-geometrical framework. Two heavy leptons are added to the Standard Model, each one sharing a double opposite electric charge and an own lepton flavor number The novel mathematical theory of almost-commutative geometry [1] wishes to unify gauge models wit

V. P. Konchakovski, S. Haussler, M. I. Gorenstein, E. L. Bratkovskaya

Event-by-event multiplicity fluctuations in nucleus-nucleus collisions are studied within the HSD and UrQMD transport models. The scaled variances of negative, positive, and all charged hadrons in Pb+Pb at 158 AGeV are analyzed in comparison to the data from the NA49 Collaboration. We find a dominant role of the fluctuations in the nucleon participant number

Shi Zhou, Guo-Qiang Zhang, Guo-Qing Zhang

We present the first complete measurement of the Chinese Internet topology at the autonomous systems (AS) level based on traceroute data probed from servers of major ISPs in mainland China. We show that both the Chinese Internet AS graph and the global Internet AS graph can be accurately reproduced by the Positive-Feedback Preference (PFP) model with the sam

A. Kohen, Th. Proslier, T. Cren, Y. Noat

We address the question of probing the supercurrents in superconducting (SC) samples on a local scale by performing Scanning Tunneling Spectroscopy (STS) experiments with a SC tip. In this configuration, we show that the tunneling conductance is highly sensitive to the Doppler shift term in the SC quasiparticle spectrum of the sample, thus allowing the local

Carlos Kenig, Daniel Pollack, Gigliola Staffilani, Tatiana Toro

This paper has been withdrawn by the authors.

Bertrand Chauvineau, Sophie Pireaux, Tania Regimbau, Jean-Yves Vinet

The joint ESA/NASA LISA mission consists in three spacecraft on heliocentric orbits, flying in a triangular formation of 5 Mkm each side, linked by infrared optical beams. The aim of the mission is to detect gravitational waves in a low frequency band. For properly processing the science data, the propagation delays between spacecraft must be accurately know

Valter Moretti

In a previous paper (hep-th/0407256) local scalar QFT (in Weyl algebraic approach) has been constructed on degenerate semi-Riemannian manifolds $\bS^1\times Σ$ corresponding to the extension of Killing horizons by adding points at infinity to the null geodesic forming the horizon. It has been proved that the theory admits a natural representation of $PSL(2,\

E. Di Salvo

New properties of the quark correlator are found via equations of motion. As a first result, approximate relations can be established among the "soft" functions; one such relation may help in determining the quark transversity in a nucleon. Secondly, the Q^2 dependence of the T-odd functions is deduced; the result is compared to unpolarized Drell-Yan data. L

A. M. Cooper-Sarkar

Use of HERA jet production cross sections can extend our knowledge of the gluon parton distribution function and yield accurate measurements of $\alpha_s(M_Z)$ in addition to illustrating the running of $\alpha_s$ with scale.

Maria C. Babiuc, Bela Szilagyi, Jeffrey Winicour

Computational methods are essential to provide waveforms from coalescing black holes, which are expected to produce strong signals for the gravitational wave observatories being developed. Although partial simulations of the coalescence have been reported, scientifically useful waveforms have so far not been delivered. The goal of the AppleswithApples (AwA)

Tatsushi Matsubayashi, Junichiro Makino, Toshikazu Ebisuzaki

Resent observations and theoretical interpretations suggest that IMBHs (intermediate-mass black hole) are formed in the centers of young and compact star clusters born close to the center of their parent galaxy. Such a star cluster would sink toward the center of the galaxy, and at the same time stars are stripped out of the cluster by the tidal field of the

N. Oelkers, M. T. Batchelor, M. Bortz, X. W. Guan

We extend the exact periodic Bethe Ansatz solution for one-dimensional bosons and fermions with delta-interaction and arbitrary internal degrees of freedom to the case of hard wall boundary conditions. We give an analysis of the ground state properties of fermionic systems with two internal degrees of freedom, including expansions of the ground state energy

Camille Laurent-Gengoux, Mathieu Stienon, Ping Xu

We study non-abelian differentiable gerbes over stacks using the theory of Lie groupoids. More precisely, we develop the theory of connections on Lie groupoid $G$-extensions, which we call "connections on gerbes", and study the induced connections on various associated bundles. We also prove analogues of the Bianchi identities. In particular, we deve

J. Ponce de Leon

We consider the scenario where our observable universe is devised as a dynamical four-dimensional hypersurface embedded in a five-dimensional bulk spacetime, with a large extra dimension, which is the {\it generalization of the flat FRW cosmological metric to five dimensions}. This scenario generates a simple analytical model where different stages of the ev

Rina Kanamoto, Hiroki Saito, Masahito Ueda

We employ mean-field, Bogoliubov, and many-body theories to study critical fluctuations in position and momentum of a Bose-Einstein condensate whose translation symmetry is spontaneously broken due to attractive interactions. In a homogeneous system, the many-body ground state of the symmetry-preserving Hamiltonian is very fragile against superposition of lo

Dmitry Solenov, Denis Tolkunov, Vladimir Privman

We obtain and analyze the indirect exchange interaction between two two-state systems, e.g., spins, in a formulation that also incorporates the quantum noise that they experience, due to a bosonic environment, for instance, phonons. We utilize a perturbative approach to obtain a quantum evolution equation for the two-spin dynamics. A non-perturbative approac

M. Cinal, A. Umerski

The uniaxial in-plane magnetic anisotropy (UIP-MA) constant is calculated for a single step on the (001) surface of fcc Co($N$) films. The calculations are done for both an undecorated step and the step decorated with one or more, up to 7, Cu wires. Our objective is to explain the mechanisms by which the decoration decreases the UIP-MA constant, which is the

V. Kreiman

We give an explicit Grobner basis for the ideal of the tangent cone at any T-fixed point of a Richardson variety in the Grassmannian, thus generalizing a result of Kodiyalam-Raghavan and Kreiman-Lakshmibai. Our proof is based on a generalization of the Robinson-Schensted-Knuth (RSK) correspondence, which we call the bounded RSK (BRSK). We use the Grobner bas

David Aldous

Consider routing traffic on the N x N torus, simultaneously between all source-destination pairs, to minimize the cost $\sum_ec(e)f^2(e)$, where f(e) is the volume of flow across edge e and the c(e) form an i.i.d. random environment. We prove existence of a rescaled $N\to \infty$ limit constant for minimum cost, by comparison with an appropriate analogous pr

C. Hicke, L. F. Santos, M. I. Dykman

We present a method to perform fault-tolerant single-qubit gate operations using Landau-Zener tunneling. In a single Landau-Zener pulse, the qubit transition frequency is varied in time so that it passes through the frequency of the radiation field. We show that a simple three-pulse sequence allows eliminating errors in the gate up to the third order in erro

Th. Baier, K. M. Hangos, A. Magyar, D. Petz

In the paper the Bayesian and the least squares methods of quantum state tomography are compared for a single qubit. The quality of the estimates are compared by computer simulation when the true state is either mixed or pure. The fidelity and the Hilbert-Schmidt distance are used to quantify the error. It was found that in the regime of low measurement numb

S. Slama, C. von Cube, M. Kohler, C. Zimmermann

We study Bragg scattering at 1D atomic lattices. Cold atoms are confined by optical dipole forces at the antinodes of a standing wave generated inside a laser-driven cavity. The atoms arrange themselves into an array of lens-shaped layers located at the antinodes of the standing wave. Light incident on this array at a well-defined angle is partially Bragg-re

C. von Cube, S. Slama, M. Kohler, C. Zimmermann

Ultracold atoms interacting with the optical modes of a high-Q optical ring cavity can synchronize their motion. The collective behavior makes the system interesting for quantum computing applications. This paper is devoted to the study of the collective coupling. We report on the first observation of a collective dynamics and on the realization of a laser,

Guilherme Temporao, Sebastien Tanzilli, Hugo Zbinden, Nicolas Gisin

We report a procedure to detect mid-infrared single photons at 4.65 um via a two-stage scheme based on Sum Frequency Generation, using a Periodically Poled Lithium Niobate (PPLN) nonlinear crystal and a Silicon Avalanche Photodiode. An experimental investigation shows that, in addition to a high timing resolution, this technique yields a detection sensitivit

A. Sinha, P. Roy

We study $(1+1)$ dimensional Dirac equation with non Hermitian interactions, but real energies. In particular, we analyze the pseudoscalar and scalar interactions in detail, illustrating our observations with some examples. We also show that the relevant hidden symmetry of the Dirac equation with such an interaction is pseudo supersymmetry.

T. N. Palmer

The mathematical notion of incompleteness (eg of rational numbers, Turing-computable functions, and arithmetic proof) does not play a key role in conventional physics. Here, a reformulation of the kinematics of quantum theory is attempted, based on an inherently granular and discontinuous state space, in which the quantum wavefunction is associated with a fi

C. P. Sun, Yu-xi Liu, L. F. Wei, Franco Nori

We propose a novel method to generate non-classical states of a single-mode microwave field, and to produce macroscopic cat states by virtue of a three-level system with $Δ$-shaped (or cyclic) transitions. This exotic system can be implemented by a superconducting quantum circuit with a broken symmetry in its effective potential. Using the cyclic population

Lucas S. Furtado, Mauro Copelli

Experimental data suggest that some classes of spiking neurons in the first layers of sensory systems are electrically coupled via gap junctions or ephaptic interactions. When the electrical coupling is removed, the response function (firing rate {\it vs.} stimulus intensity) of the uncoupled neurons typically shows a decrease in dynamic range and sensitivit

Filipe Tostevin, Martin Howard

The Min system in Escherichia coli directs division to the centre of the cell through pole-to-pole oscillations of the MinCDE proteins. We present a one dimensional stochastic model of these oscillations which incorporates membrane polymerisation of MinD into linear chains. This model reproduces much of the observed phenomenology of the Min system, including

J. B. Coe, Y. Mao

The Penna model is a model of evolutionary ageing through mutation accumulation where traditionally time and the age of an organism are treated as discrete variables and an organism's genome by a binary bit string. We reformulate the asexual Penna model and show that, a universal scale invariance emerges as we increase the number of discrete genome bits

Morten Bache, Hanne Nielsen, Jesper Lægsgaard, Ole Bang

We consider an index-guiding silica photonic crystal fiber with a triangular air-hole structure and a poled quadratic nonlinearity. By tuning the pitch and the relative hole size, second-harmonic generation with zero group-velocity mismatch is found for any fundamental wavelength above 780 nm. The phase-velocity mismatch has a lower limit with coherence leng

Jonas Latt, Bastien Chopard, Paul Albuquerque

In multiscale, multi-physics applications, there is an increasing need for coupling numerical solvers that are each applied to a different part of the problem. Here we consider the case of coupling a Lattice Boltzmann fluid model and a Finite Difference Navier-Stokes solver. The coupling is implemented so that the entire computational domain can be divided i

Zine Fellah, Jean-Philippe Groby, Erick Ogam, Thierry Scotti

We show how to cope with the acoustic identification of poroelastic materials when the specimen is in the form of a cylinder. We apply our formulation, based on the Biot model, approximated by the equivalent elastic solid model, to a long bone-like or borehole sample specimen probed by low frequency sound.

D. Kielpinski, M. Cetina, J. A. Cox, F. X. Kaertner

We demonstrate an ultraviolet diode laser system for cooling of trapped ytterbium ions. The laser power and linewidth are comparable to previous systems based on resonant frequency doubling, but the system is simpler, more robust, and less expensive. We use the laser system to cool small numbers of ytterbium ions confined in a linear Paul trap. From the obse

Toru Morishita, Shinichi Watanabe, C. D. Lin

We illustrate how attosecond light pulses can be used to directly mapping out the time-dependence of the correlated motion of two excited atomic electrons, discuss how the two-electron correlations manifest themselves in realistic attosecond measurements, and propose the following for experimental exploration: (a) The single ionization signals which directly

D. B. Blaschke, A. V. Prozorkevich, C. D. Roberts, S. M. Schmidt

Electron-positron pair creation in a standing wave is explored using a parameter-free quantum kinetic equation. Field strengths and frequencies corresponding to modern optical lasers induce a material polarisation of the QED vacuum, which may be characterised as a plasma of e^+ e^- quasiparticle pairs with a density of ~10^{20}cm^{-3}. The plasma vanishes al

A. Dumitru, L. Portugal, D. Zschiesche

A QCD phase transition may reflect in a inhomogeneous decoupling surface of hadrons produced in relativistic heavy-ion collisions. We show that due to the non-linear dependence of the particle densities on the temperature and baryon-chemical potential such inhomogeneities should be visible even in the integrated, inclusive abundances. We analyze experimental

A. Nogga, P. Navratil, B. R. Barrett, J. P. Vary

Using the no-core shell model approach, we report on the first results for 7Li based on the next-to-next-to-leading order chiral nuclear interaction. Both, two-nucleon and three-nucleon interactions are taken into account. We show that the p-shell nuclei are sensitive to the subleading parts of the chiral interactions including three-nucleon forces. Though c

J. C. Hardy, I. S. Towner, G. Savard

A recent Penning-trap measurement of the masses of 46V and 46Ti leads to a Qec value that disagrees significantly with the previously accepted value, and destroys overall consistency among the nine most precisely characterized T=1 superallowed beta emitters. This raises the possibility of a systematic discrepancy between Penning-trap measurements and the rea

D. Schuermann, A. Di Leva, L. Gialanella, D. Rogalla

The total cross section of 12C(alpha,gamma)16O was measured for the first time by a direct and ungated detection of the 16O recoils. This measurement in inverse kinematics using the recoil mass separator ERNA in combination with a windowless He gas target allowed to collect data with high precision in the energy range E=1.9 to 4.9 MeV. The data represent new

E. V. Ferapontov, K. R. Khusnutdinova

An invariant differential-geometric approach to the integrability of (2+1)-dimensional systems of hydrodynamic type u_t+A(u)u_x+B(u)u_y=0 is developed. It is proved that the existence of special solutions known as `double waves' is equivalent to the diagonalizability of an arbitrary matrix of the two-parameter family (kE+A)^{-1}(lE+B). Since the diagonal

Eugene Kanzieper, Gernot Akemann

The integrable structure of Ginibre's Orthogonal Ensemble of random matrices is looked at through the prism of the probability "p_{n,k}" to find exactly "k" real eigenvalues in the spectrum of an "n" by "n" real asymmetric Gaussian random matrix. The exact solution for the probability function "p_{n,k}" is presente

Jan Philip Solovej

We prove upper bounds on the ground state energies of the one- and two-component charged Bose gases. The upper bound for the one-component gas agrees with the high density asymptotic formula proposed by L. Foldy in 1961. The upper bound for the two-component gas agrees in the large particle number limit with the asymptotic formula conjectured by F. Dyson in

J. O. Button

We present an algorithm which, given any finite presentation of a group as input, will terminate with answer yes if and only if the group is large. We use this to prove that a mapping torus of a finitely generated free group automorphism is large if it contains the integers times the integers as a subgroup of infinite index. We then extend this result to map

Lizhong Peng, Genkai Zhang

Consider a root system of type $BC_1$ on the real line $\mathbb R$ with general positive multiplicities. The Cherednik-Opdam transform defines a unitary operator from an $L^2$-space on $\mathbb R$ to a $L^2$-space of $\mathbb C^2$-valued functions on $\mathbb R^+$ with the Harish-Chandra measure $|c(\lam)|^{-2}d\lam$. By introducing a weight function of the

Ronald Fintushel, Ronald J. Stern

In this note we fill a gap in the proof of the main theorem (Theorem 1.2) of our paper 'Surfaces in 4-manifolds', Math. Res. Letters 4 (1997), 907-914.

Axel Kohnert, Sascha Kurz

A Diophantine figure is a set of points on the integer grid $\mathbb{Z}^{2}$ where all mutual Euclidean distances are integers. We also speak of Diophantine graphs. In this language a Diophantine figure is a complete Diophantine graph. Due to a famous theorem of Erdős and Anning there are complete Diophantine graphs which are not contained in larger ones. We

Sascha Kurz

We generalise the definition of the characteristic of an integral triangle to integral simplices and prove that each simplex in an integral point set has the same characteristic. This theorem is used for an efficient construction algorithm for integral point sets. Using this algorithm we are able to provide new exact values for the minimum diameter of integr

Idrisse Khemar

We study supersymmetric harmonic maps from the point of view of integrable system. It is well known that harmonic maps from R^2 into a symmetric space are solutions of a integrable system . We show here that the superharmonic maps from R^{2|2} into a symmetric space are solutions of a integrable system, more precisely of a first elliptic integrable system in

Romain Abraham, Jean-Francois Delmas

We consider the height process of a Levy process with no negative jumps, and its associated continuous tree representation. Using Levy snake tools developed by Duquesne and Le Gall, with an underlying Poisson process, we construct a fragmentation process, which in the stable case corresponds to the self-similar fragmentation described by Miermont. For the ge

Charles Torossian

We use Dunkl's operators to give an elementary proof of the surjectivity in the Chevalley's restriction theorem. In the second part of this article we describe the image of the invariants by the restriction map in the case of Takiff algebras. We extend this result to Takiff symmetric spaces.

Amitava Bhattacharya, Uri N. Peled, Murali K. Srinivasan

We consider a graph with colored edges. A trail (vertices may repeat but not edges) is called \emph{alternating} when successive edges have different colors. Given a set of vertices called \emph{terminals}, the \emph{alternating reachability} problem is to find an alternating trail connecting distinct terminals, if one exists. A special case with two colors

Frank Schuhmacher

We show that three deformation functors (deformations of the product, flat deformations and deformations of the relations) assigned to an associative algebra are naturally isomorphic.

Keith M. Rogers

A K^n_2-set is a set of zero Lebesgue measure containing a translate of every plane in an (n-2)-dimensional manifold in Gr(n,2), where the manifold fulfills a curvature condition. We show that this is a natural class of sets with respect to the Kakeya problem and prove that dim_H(E)\ge 7/2 for all K^4_2-sets E. When the underlying field is replaced by the co

Anna Karczewska

The note is devoted to estimates for convolutions appearing in some class of stochastic Volterra equations. Two maximal inequalities and exponential tail estimate are proved by the fractional method of infinite dimensional stochastic calculus. The paper extends on non-semigroup case some results obtained earlier for semigroups.