October 2008 arXiv papers — page 11

F. Perez

We present theoretical aspects of spin polarized two dimensional electron gas (SP2DEG) which can be achieved in doped semimagnetic quantum wells. This original model system has been recently studied by magneto Raman scattering experiments has given a new access to spin resolved excitations and spectrum of the SP2DEG. Starting from the Diluted Magnetic Semico

Jonah N. Gollub, David R. Smith, Juan D. Baena

We explore the hybridization of fundamental material resonances with the artificial resonances of metamaterials. A hybrid structure is presented in the waveguide environment that consists of a resonant magnetic material with a characteristic tuneable gyromagnetic response that is integrated into a complementary split ring resonator (CSRR) metamaterial struct

Y. Itoh, N. Moritsu, K. Yoshimura

We report 7Li NMR studies of V-substitution effects on spinel oxide superconductor LiTi2O4 (Tc = 13.4 K). In LiTi2-xVxO4 (x = 0-0.4), the V substitution for the Ti site suppressed the relative volume fraction of superconductivity faster than Tc. From the observation of fairly homogeneous enhancement in a 7Li nuclear spin-lattice relaxation rate, we conclude

Shaun A. Thomas, Filipe B. Abdalla, Jochen Weller

The idea that we live in a Universe undergoing a period of acceleration is a strongly held notion in cosmology. As this can, potentially, be explained with a modification to General Relativity we look at current cosmological data with the purpose of testing aspects of gravity. Firstly we constrain a phenomenological model (mDGP) motivated by a possible extra

Stéphane Bedwani, Daniel Wegner, Michael F. Crommie, Alain Rochefort

The interaction of the strong electron-acceptor tetracyanoethylene (TCNE) with the Cu(100) surface has been studied with scanning tunneling microscopy experiments and first-principles density functional theory calculations. We compare two different adsorption models with the experimental results and show that the molecular self-assembly is caused by a strong

Olof Görnerup, Martin Nilsson Jacobi

We apply Markov chain lumping techniques to aggregate codons from an empirical substitution matrix. The standard genetic code as well as higher order amino acid substitution groups are identified. Since the aggregates are derived from first principles they do not rely on system dependent assumptions made beforehand, e.g. regarding criteria on what should con

Svjetlana Fajfer, Nejc Kosnik

Recently it was noticed that among many scenarios of new physics leptoquarks might compensate for the disagreement between the lattice and experimental results for the charmed strange meson decay constant. The leptoquarks might modify also the flavor changing neutral current charm decays. In this study we investigate impact of the scalar leptoquark with elec

Roland Zeyher

A theory for the dispersion of collective magnetic excitations in superconducting cuprates is presented with the aim to cover both high and low doping regimes. Besides of spin fluctuations describable in the random phase approximation (RPA) we allow for local spin rotations within a mode-coupling theory. At low temperatures and moderately large correlation l

Jerome Bouvier

I review the development of ideas regarding the angular momentum evolution of solar-type stars, from the early 60's to the most recent years. Magnetic fields are the central agent that dictates the rotational evolution of solar-type stars, both during the pre-main sequence, through star-disk magnetic coupling, and during the main sequence, through magnet

J. Dressel, S. G. Rajeev, J. C. Howell, A. N. Jordan

We explore the nature of the classical propagation of light through media with strong frequency-dependent dispersion in the presence of a gravitational field. In the weak field limit, gravity causes a redshift of the optical frequency, which the slow-light medium converts into a spatially-varying index of refraction. This results in the bending of a light ra

N. Akopov, L. Grigoryan, Z. Akopov

In this paper it is demonstrated that based on two-dimensional distributions in semi-inclusive deep inelastic scattering (SIDIS) data, obtained recently by the HERMES experiment at DESY on different nuclei, which contains data for charged pions produced in $z$ slices as a function of $ν$, and in a $ν$ slices as a function of $z$, it it is possible to paramet

Matti Peltomaki, Martin Rost, Mikko Alava

Interacting populations often create complicated spatiotemporal behavior, and understanding it is a basic problem in the dynamics of spatial systems. We study the two-species case by simulations of a host--parasitoid model. In the case of co-existence, there are spatial patterns leading to noise-sustained oscillations. We introduce a new measure for the patt

A. Liebsch, H. Ishida, J. Merino

The influence of short-range Coulomb correlations on the Mott transition in the single-band Hubbard model at half-filling is studied within cellular dynamical mean field theory for square and triangular lattices. Finite-temperature exact diagonalization is used to investigate correlations within two-, three-, and four-site clusters. Transforming the non-loca

Sylvain E. Cappell, Edward Y. Miller

The work of Ray and Singer which introduced analytic torsion, a kind of determinant of the Laplacian operator in topological and holomorphic settings, is naturally generalized in both settings. The couplings are extended in a direct way in the topological setting to general flat bundles and in the holomorphic setting to bundles with (1,1) connections, which

S. Feltzing, F. Primas, R. A. Johnson

[ABRIDGED] Metal-rich globular clusters provide important tracers of the formation of our Galaxy. Moreover, and not less important, they are very important calibrators for the derivation of properties of extra-galactic metal-rich stellar populations. Nonetheless, only a few of the metal-rich globular clusters in the Milky Way have been studied using high-res

Erik Devetak

We present a study of experimental determination of the Wtb anomalous couplings in the $t\bar{t}$ process at the International Linear Collider in the framework of effective field theory. The theory predicts several observables that are particularly sensitive to the couplings including the asymmetry of the bottom quark angular distributions. These observables

M. M. Miller Bertolami, L. G. Althaus, K. Unglaub, A. Weiss

We present 1D numerical simulations aimed at studying the hot-flasher scenario for the formation of He-rich subdwarf stars. Sequences were calculated for a wide range of metallicities and with the He core flash at different points of the post-RGB evolution (i.e. different remnant masses). We followed the complete evolution from the ZAMS, through the hot-flas

Gunnar Carlsson

We describe the construction which takes as input a profinite group, which when applied the the absolute Galois group of a geometric field F agrees in some cases with the algebraic K-theory of F. We prove that it agrees in the case of a topologically finitely generated abelian absolute Galois group, and conjecture that it agrees for all geometric fields. We

Luiz Carlos Ryff

It is shown that the model introduced by Cabello et al. to criticize the Franson experiment suffers from the same weakness as the previous model introduced by Aerts et al. with the same purpose. It is also shown why we can assume with confidence that the Franson experiment does violate local realism.

Roland Duclous, Bruno Dubroca, Francis Filbet, Vldimir Tikhonchuk

A high order, deterministic direct numerical method is proposed for the nonrelativistic $2D_{\bf x} \times 3D_{\bf v}$ Vlasov-Maxwell system, coupled with Fokker-Planck-Landau type operators. Such a system is devoted to the modelling of electronic transport and energy deposition in the general frame of Inertial Confinement Fusion applications. It describes t

John Southworth, B T Gaensicke, T R Marsh

The Sloan Digital Sky Survey has identified a total of 212 cataclysmic variables, most of which are fainter than 18th magnitude. This is the deepest and most populous homogeneous sample of cataclysmic variables to date, and we are undertaking a project to characterise this population. We have found that the SDSS sample is dominated by a great ``silent majori

V. I. Yukalov, V. K. Henner, P. V. Kharebov, E. P. Yukalova

The peculiarities of coherent spin radiation by magnetic nanomolecules is investigated by means of numerical simulation. The consideration is based on a microscopic Hamiltonian taking into account realistic dipole interactions. Superradiance can be realized only when the molecular sample is coupled to a resonant electric circuit. The feedback mechanism allow

Peter Hall, Soumendra N. Lahiri

When using the bootstrap in the presence of measurement error, we must first estimate the target distribution function; we cannot directly resample, since we do not have a sample from the target. These and other considerations motivate the development of estimators of distributions, and of related quantities such as moments and quantiles, in errors-in-variab

Sibusiso Sibisi

Li showed that the Riemann Hypothesis is equivalent to the nonnegativity of a certain sequence of numbers. Bombieri and Lagarias gave an arithmetic formula for the number sequence based on the Guinand-Weil explicit formula and showed that Li's criterion is equivalent to Weil's criterion for the Riemann Hypothesis. We provide a derivation of the expli

Yuan Chao

The "Underlying Event" at CMS (under nominal and start-up conditions) is studied by examining charged particle and momentum densities in the "transverse" region in charged particle jet production. The predictions of various QCD models with different multiple parton interaction schemes correctly reproduce Tevatron data, however they fail to ag

Roberto Macovez, Andrea Goldoni, Luca Petaccia, Ingrid Marenne

The simple cubic phase of a RbC60 thin film has been studied using photoelectron spectroscopy. The simple cubic-to-dimer transition is found to be reversible at the film surface. A sharp Fermi edge is observed and a lower limit of 0.5 eV is found for the surface Hubbard U, pointing to a strongly-correlated metallic character of thin-film simple cubic RbC60.

Yuan Chao

The two $B$-factories, Belle and BaBar, has been played major roles in the B decays study. Their wonderful design and excellent operation enables their fruitful analysis results. Also recently the Tevatron experiments, CDF and DO, join the game with their $B_S$ studies. From the experimental results of $B$ decay studies, we learn that most of measurements ar

T. Masson

Some derivation-based differential calculi which have been used to construct models of noncommutative gauge theories are presented and commented. Some comparisons between them are made.

Keisuke Izumi, Takahiro Tanaka

We revisit the problem of the helicity-0 ghost mode of massive graviton in the de Sitter background. In general, the presence of a ghost particle, which has negative energy, drives the vacuum to be unstable through pair production of ghost particles and ordinary particles. In the case that the vacuum state preserves the de Sitter invariance, the number densi

T. Grust, M. Mayr, J. Rittinger

A purely relational account of the true XQuery semantics can turn any relational database system into an XQuery processor. Compiling nested expressions of the fully compositional XQuery language, however, yields odd algebraic plan shapes featuring scattered distributions of join operators that currently overwhelm commercial SQL query optimizers. This work re

Li-Shan Huang, Jianwei Chen

This paper provides ANOVA inference for nonparametric local polynomial regression (LPR) in analogy with ANOVA tools for the classical linear regression model. A surprisingly simple and exact local ANOVA decomposition is established, and a local R-squared quantity is defined to measure the proportion of local variation explained by fitting LPR. A global ANOVA

Strashimir G. Popvassilev

We show that for every positive integer n there is a simple closed curve in the plane (which can be taken infinitely differentiable and convex) which has exactly n inscribed squares.

Vincent Koziarz, Julien Maubon

We propose a definition of the Toledo invariant for representations of fundamental groups of smooth varieties of general type into semisimple Lie groups of Hermitian type. This definition allows to generalize the results known in the classical case of representations of complex hyperbolic lattices to this new setting: assuming that the rank of the target Lie

Sergio Campana, Luigi Stella, Gianluca Israel, Paolo D'Avanzo

We present X-ray observations of the transient accretion-powered millisecond pulsar IGR J00291+5934 during quiescence. IGR J00291+5934 is the first source among accretion powered millisecond pulsars to show signs of a thermal component in its quiescent spectrum. Fitting this component with a neutron star atmosphere or a black body model we obtain soft temper

I. Braun, J. Engler, J. R. Hörandel, J. Milke

Since 1993, a muon telescope located at Forschungszentrum Karlsruhe (Karlsruhe Muon Telescope) has been recording the flux of single muons mostly originating from primary cosmic-ray protons with dominant energies in the 10 - 20 GeV range. The data are used to investigate the influence of solar effects on the flux of cosmic-rays measured at Earth. Non-periodi

Lawrence D. Brown, T. Tony Cai, Harrison H. Zhou

In this paper we develop a nonparametric regression method that is simultaneously adaptive over a wide range of function classes for the regression function and robust over a large collection of error distributions, including those that are heavy-tailed, and may not even possess variances or means. Our approach is to first use local medians to turn the probl

L. Kuiper, P. R. den Hartog, W. Hermsen

In this paper the current status of high-energy research on the hard X-ray characteristics of the persistent emission from magnetars is reviewed. Focus is put on recent intriguing results for 1RXS J1708-40, from phase resolved spectral analysis over a 2 decades wide energy band (~3-300 keV) combining contemporaneous RXTE, XMM and INTEGRAL data. For 1E 1841-0

M. E. Carrington, A. Rebhan

In this paper the structure of the next-to-leading (NLO) static gluon self energy for an anisotropic plasma is investigated in the limit of a small momentum space anisotropy. Using the Ward identities for the static hard-loop (HL) gluon polarization tensor and the (nontrivial) static HL vertices, we derive a comparatively compact form for the complete NLO co

Wei Wu, Tianping Chen

For networks of pulse-coupled oscillators with delayed excitatory coupling, we analyze the firing behaviors depending on coupling strength and transmission delay. The parameter space consisting of strength and delay is partitioned into two regions. For one region, we derive a low bound of interspike intervals, from which three firing properties are obtained.

Oleg Makarenkov

In this paper the statement of the second Bogolyubov's theorem on periodic solutions of smooth systems with small parameter is justified for discountinuous systems. It is assumed that the generating solution intersects the discontinuity hyperplanes transversally and that the system is smooth outside of these hyperplanes. Such a situation is natural for m

Nandini Nag, Sutapa Ghosh, Roni Saha, Somenath Chakrabarty

Following some of the recent articles on hole super-conductivity and related phenomena by Hirsch \cite{H1,H2,H3}, a simple model is proposed to explain the observed low surface magnetic field of the expected quark stars. It is argued that the diamagnetic moments of the electrons circulating in the electro-sphere induce a magnetic field, which forces the exis

M. I. Kalinin

In this article it is shown that in an equilibrium classical canonical ensemble of molecules with two-body interaction and external field full Gibbs distribution can be uniquely expressed in terms of a reduced two-particle distribution function. This means that while a number of particles $N$ and a volume $V$ are fixed the reduced two-particle distribution f

Dagfinn F. Vatne

We give an explicit description of the mutation class of quivers of type D.

L. J. P. Kilford

In this article we will show how to compute $U_p$ acting on spaces of overconvergent $p$-adic modular forms when $X_0(p)$ has genus 1. We first give a construction of Banach bases for spaces of overconvergent $p$-adic modular forms, and then give an algorithm to approximate both the characteristic power series of the $U_p$ operator and eigenvectors of finite

J. Tworzydlo, C. W. Groth, C. W. J. Beenakker

We adapt a finite difference method of solution of the two-dimensional massless Dirac equation, developed in the context of lattice gauge theory, to the calculation of electrical conduction in a graphene sheet or on the surface of a topological insulator. The discretized Dirac equation retains a single Dirac point (no "fermion doubling"), avoids inte

David Brizuela, Jose M. Martin-Garcia

We develop the Hamiltonian theory of axial perturbations around a general time-dependent spherical background spacetime. Using the fact that the linearized constraints are gauge generators, we isolate the physical and unconstrained axial gravitational wave in a Hamiltonian pair of variables. Then, switching to a more geometrical description of the system, we

C. Thanassoulas, V. Klentos, G. Verveniotis, N. Zymaris

In order to investigate the capability of the preseismic electric field "strange attractor like" precursor as a time predictor of a large EQ within a short time window (short-term prediction), the specific methodology was applied on the Earth's electric field recorded during a rather long seismically active period (December 1st, 2007 - April 30th

Norbert Grewe, Torben Jabben, Sebastian Schmitt

The low energy region of certain transition metal compounds reveals dramatic correlation effects between electrons, which can be studied by photoelectron spectroscopy. Theoretical investigations are often based on multi-orbital impurity models, which reveal modified versions of the Kondo effect. We present a systematic study of a multi-orbital Anderson-like

Evelyne Miot

We study a complex Ginzburg-Landau equation in the plane, which has the form of a Gross-Pitaevskii equation with some dissipation added. We focus on the regime corresponding to well-prepared unitary vortices and derive their asymptotic motion law.

Dany Vanbeveren

The present paper reviews massive star (initial mass smaller than 120 M0) and very massive star (initial mass larger than 120 M0) evolution. I will focus on evolutionary facts and questions that may critically affect predictions of population and spectral synthesis of starburst regions. We discuss the ever-lasting factor 2 or more uncertainty in the stellar

T. Tony Cai, Lie Wang

We consider a wavelet thresholding approach to adaptive variance function estimation in heteroscedastic nonparametric regression. A data-driven estimator is constructed by applying wavelet thresholding to the squared first-order differences of the observations. We show that the variance function estimator is nearly optimally adaptive to the smoothness of bot

D. Cseh, A. Fuhl, S. Frey

We show an archival 1.4-GHz Very Large Array (VLA) image of the core-dominated triple (CDT) radio source J1628+3906, along with a recent high-resolution 5-GHz Very Long Baseline Interferometry (VLBI) image of its core. This core is resolved into two nearly symmetric components at ~10 milli-arcsecond (mas) angular scale. The inner structure is markedly misali

S. Frey, K. E. Gabanyi, Y. Asaki

We apply an efficient selection method to identify potential weak Very Long Baseline Interferometry (VLBI) target quasars simply using optical (SDSS) and low-resolution radio (FIRST) catalogue data. Our search is restricted to within 12" from known compact radio sources that are detectable as phase-reference calibrators for ASTRO-G at 8.4 GHz frequency.

Peter Schenzel

Let $I$ denote an ideal of a local Gorenstein ring $(R, \mathfrak m)$. Then we show that the local cohomology module $H^c_I(R), c = \height I,$ is indecomposable if and only if $V(I_d)$ is connected in codimension one. Here $I_d$ denotes the intersection of the highest dimensional primary components of $I.$ This is a partial extension of a result shown by Ho

E. Kankare, M. Hanski, G. Theureau, P. Teerikorpi

Aims. We attempt to determine the optical depth of spiral galaxy disks by a statistical study of new Tully-Fisher data from the ongoing KLUN+ survey, and to clarify the difference between the true and apparent behavior of optical depth. Methods. By utilizing so-called normalized distances, a subsample of the data is identified to be as free from selection ef

Christina V. Kraus, Michael M. Wolf, J. Ignacio Cirac, Geza Giedke

The notion of "paired" fermions is central to important condensed matter phenomena such as superconductivity and superfluidity. While the concept is widely used and its physical meaning is clear there exists no systematic and mathematical theory of pairing which would allow to unambiguously characterize and systematically detect paired states. We pro

Francesco Piazza, Paolo De Los Rios, Fabio Cecconi

Normal mode analysis is a widely used technique for reconstructing conformational changes of proteins from the knowledge of native structures. In this Letter, we investigate to what extent normal modes capture the salient features of the dynamics over a range of temperatures from close to T = 0 to above unfolding. We show that on the one hand, the use of nor

N. M. R. Peres, J. N. B. Rodrigues, T. Stauber, J. M. B. Lopes dos Santos

In this paper we analyse the electronic properties of Dirac electrons in finite-size ribbons and in circular and hexagonal quantum dots made of graphene.

Zi-Xiang Zhou

A Lax system in three variables is presented, two equations of which form the Lax pair of the stationary Davey-Stewartson II equation. With certain nonlinear constraints, the full integrability condition of this Lax system contains the hyperbolic Nizhnik-Novikov-Veselov equation and its standard Lax pair. The Darboux transformation for the Davey-Stewartson I

Bintao Cao

Navier equations are used to describe the deformation of a homogeneous, isotropic and linear elastic medium in the absence of body forces. Mathematically, the system is a natural vector (field) $O(n,\mbb{R})$-invariant generalization of the classical Laplace equation, which physically describes the vibration of a string. In this paper, we decompose the space

Makoto Maejima, Ciprian Tudor

Let $B^{H,K}=(B^{H,K}_{t}, t\geq 0)$ be a bifractional Brownian motion with two parameters $H\in (0,1)$ and $K\in(0,1]$. The main result of this paper is that the increment process generated by the bifractional Brownian motion $(B^{H,K}_{h+t} -B^{H,K}_{h}, t\geq 0)$ converges when $h\to \infty$ to $(2^{(1-K)/{2}}B^{HK}_{t}, t\geq 0)$, where $(B^{HK}_{t}, t\g

Tamas G. Kovacs

Using the overlap Dirac operator I show that, contrary to some expectations, even well above the critical temperature there is not necessarily a gap in the Dirac spectrum in pure SU(2) gauge theory. This happens when the Polyakov loop and the fermion boundary condition combine to give close to periodic boundary condition for the fermions in the time directio

S. Renner, H. Rauer, A. Erikson, P. Hedelt

The pioneer space mission for photometric exoplanet searches, CoRoT, steadily monitors about 12000 stars in each of its fields of view. Transit detection algorithms are applied to derive promising planetary candidates, which are then followed-up with ground-based observations. We present BAST (Berlin Automatic Search for Transits), a new algorithm for period

Vincenzo Marotta, Adele Naddeo

We study the Morita equivalence for field theories on noncommutative two-tori. For rational values of the noncommutativity parameter $θ$ (in appropriate units) we show the equivalence between an abelian noncommutative field theory and a nonabelian theory of twisted fields on ordinary space. We concentrate on a particular conformal field theory (CFT), the one

Anders Frisk, Volodymyr Mazorchuk

We use the technique of Harish-Chandra bimodules to prove that regular strongly typical blocks of the category $\mathcal{O}$ for the queer Lie superalgebra $\mathfrak{q}_n$ are equivalent to the corresponding blocks of the category $\mathcal{O}$ for the Lie algebra $\mathfrak{gl}_n$.

Wei Hu, Changchang Xi

In this paper, we introduce almost $\cal D$-split sequences and establish an elementary but somewhat surprising connection between derived equivalences and Auslander-Reiten sequences via BB-tilting modules. In particular, we obtain derived equivalences from Auslander-Reiten sequences (or $n$-almost split sequences), and Auslander-Reiten triangles.

Vytas Zacharovas, Hsien-Kuei Hwang

A new approach to Poisson approximation is proposed. The basic idea is very simple and based on properties of the Charlier polynomials and the Parseval identity. Such an approach quickly leads to new effective bounds for several Poisson approximation problems. A selected survey on diverse Poisson approximation results is also given.

Oliver Stelzer-Chilton

The high-mass spectrum of lepton and photon pairs is sensitive to a broad range of new physics. Examples are extra dimensions and new gauge bosons such as the W' and Z'. Additionally, electron compositeness would result in excited electrons that decay into an electron and a photon. We report the latest results of searches for high-mass dilepton, diph

E. M. Epshtein, P. E. Zilberman

An effect is considered of alternating (high-frequency) current on the spin-valve type magnetic junction configuration. The stability with respect to small fluctuations is investigated in the macrospin approximation. When the current frequency is close to the eigenfrequency (precession frequency) of the free layer, parametric resonance occurs. Both collinear

Ulrike von Luxburg, Bernhard Schoelkopf

Statistical learning theory provides the theoretical basis for many of today's machine learning algorithms. In this article we attempt to give a gentle, non-technical overview over the key ideas and insights of statistical learning theory. We target at a broad audience, not necessarily machine learning researchers. This paper can serve as a starting poin

S. Umehara, T. Kishimoto, I. Ogawa, R. Hazama

We searched for the neutrino-less double beta decay(0nbb) of 48Ca by using CaF2(Eu) scintillators. Analysis of their pulse shapes was effective to reduce backgrounds. No events are observed in the Q-value region for the data of 3394 kg days. It gives a lower limit (90% confidence level) of T > 2.7 x 10^22 year for the half life of 0nbb of 48Ca. Combined with

Hidetsugu Sakaguchi

A high activity of reactions can be confined in a model cell with a semipermeable membrane in the Schlögl model. It is interpreted as a model of primitive metabolism in a cell. We study two generalized models to understand the creation of primitive cell systems conceptually from the view point of the nonlinear-nonequilibrium physics. In the first model, a si

S. Ghosh, T. F. Rosenbaum, G. Aeppli

The inability of systems of interacting objects to satisfy all constraints simultaneously leads to frustration. A particularly important consequence of frustration is the ability to access certain protected parts of a system without disturbing the others. For magnets such "protectorates" have been inferred from theory and from neutron scattering, but

Ryosuke Nishi, Hiroshi Miki, Akiyasu Tomoeda, Katsuhiro Nishinari

Heavy traffic congestion daily occurs at merging sections on highway. For releasing this congestion, possibility of alternative configuration of vehicles on multiple-lane road is discussed in this paper. This is the configuration where no vehicles move aside on the other lane. It has a merit in making smooth merging at an intersection or a junction due to so

S. Aoki, S. Ejiri, T. Hatsuda, N. Ishii

We study the equation of state in two-flavor QCD at finite temperature and density. Simulations are made with the RG-improved gluon action and the clover-improved Wilson quark action. Along the lines of constant physics for $m_{\rm PS}/m_{\rm V} = 0.65$ and 0.80, we compute the derivatives of the quark determinant with respect to the quark chemical potential

Chiachi Huang, Viveck R. Cadambe, Syed A. Jafar

We explore the capacity and generalized degrees of freedom of the two-user Gaussian X channel, i.e. a generalization of the 2 user interference channel where there is an independent message from each transmitter to each receiver. There are three main results in this paper. First, we characterize the sum capacity of the deterministic X channel model under a s

Minnie Y. Mao, Melanie Johnston-Hollitt, Jamie B. Stevens, Simon J. Wotherspoon

Using radio data at 1.4 GHz from the ATCA we identify five head-tail (HT) galaxies in the central region of the Horologium-Reticulum Supercluster (HRS). Physical parameters of the HT galaxies were determined along with substructure in the HRS to probe the relationship between environment and radio properties. Using a density enhancement technique applied to

David Basanta, Andreas Deutsch

Environmental and genetic mutations can transform the cells in a co-operating healthy tissue into an ecosystem of individualistic tumour cells that compete for space and resources. Various selection forces are responsible for driving the evolution of cells in a tumour towards more malignant and aggressive phenotypes that tend to have a fitness advantage over

Byoungseon Jeon, Niels Grønbech-Jensen

We present an efficient parallel algorithm for statistical Molecular Dynamics simulations of ion tracks in solids. The method is based on the Rare Event Enhanced Domain following Molecular Dynamics (REED-MD) algorithm, which has been successfully applied to studies of, e.g., ion implantation into crystalline semiconductor wafers. We discuss the strategies fo

Masaru Shibata, Hirotada Okawa, Tetsuro Yamamoto

We study nonaxisymmetric collision of two black holes (BHs) with a high velocity $v=|dx^i/dx^0|=0.6$--$0.9c$ at infinity, where $x^μ$ denotes four-dimensional coordinates. We prepare two boosted BHs for the initial condition which is different from that computed by a simple moving-puncture approach. By extrapolation of the numerical results, we find that the

Longguang Liao, Xiujun Fu, Zhilin Hou

We present a cluster covering scheme to construct the two-dimensional octagonal quasilattice. A quasi-unit cell is successfully found which is a two-color cluster similar to the Gummelt's two-color decagon in five-fold quasilattice. The quasi-unit cells overlap each other following certain covering rules and thus lead to a perfect octagonal quasilattice.

Stephen Curran

We extend Voiculescu's approach to analytic subordination through the coalgebra of the free difference quotient to non-coassociative derivation-comultiplications appearing in free probability theory. We obtain new proofs of Voiculescu's analytic subordination results for freely Markovian triples, and for multiplication of unitaries which are free wit

David Basanta, Matthias Simon, Haralambos Hatzikirou, Andreas Deutsch

Tumour progression has been described as a sequence of traits or phenotypes that cells have to acquire if the neoplasm is to become an invasive and malignant cancer. Although the genetic mutations that lead to these phenotypes are random, the process by which some of these mutations become successful and spread is influenced by the tumour microenvironment an

J. Aldegunde, Jeremy M. Hutson

We investigate the hyperfine energy levels and Zeeman splittings for homonuclear alkali-metal dimers in low-lying rotational and vibrational states, which are important for experiments designed to produce quantum gases of deeply bound molecules. We carry out density-functional theory (DFT) calculations of the nuclear hyperfine coupling constants. For nonrota

A. Qaiumzadeh, F. K. Joibari, Reza Asgari

We present numerical calculations of the impact of charge carriers-carriers interactions on the dynamical properties of quasiparticles such as renormalized velocity and quasiparticle inelastic scattering lifetime in a gapped graphene sheet. Our formalism is based on the many-body $G_0W$-approximation for the self-energy. We present results for the many-body

S. McHugh, R. Jaafar, M. P. Sarachik, Y. Myasoedov

Crystals of the molecular magnet Mn12-acetate are known to contain a small fraction of low- symmetry (minor) species with a small anisotropy barrier against spin reversal. The lower barrier leads to faster magnetic relaxation and lower coercive field. We exploit the low coercive fields of the minor species to make a direct determination of the dipole field i

D. Salart, A. Baas, C. Branciard, N. Gisin

This is the reply to the comment arXiv:0810.4452 by Kofler, Ursin, Brukner, and Zeilinger.

T. Bretz, D. Dorner, R. M. Wagner, P. Sawallisch

The MAGIC telescope is an imaging atmospheric Cherenkov telescope, designed to observe very high energy gamma-rays while achieving a low energy threshold. One of the key science goals is fast follow-up of the enigmatic and short lived gamma-ray bursts. The drive system for the telescope has to meet two basic demands: (1) During normal observations, the 72-to

Tijana T. Ivancevic, Murk J. Bottema, Lakhmi C. Jain

We propose a strange-attractor model of tumor growth and metastasis. It is a 4-dimensional spatio-temporal cancer model with strong nonlinear couplings. Even the same type of tumor is different in every patient both in size and appearance, as well as in temporal behavior. This is clearly a characteristic of dynamical systems sensitive to initial conditions.

Inês Aniceto, Antal Jevicki

We pursue the question of multi-magnon dynamics, focusing on the simplest case of magnons moving on RxS2 and working at the semiclassical level. Through a Pohlmeyer reduction, the problem reduces to another well known integrable field theory, the sine-Gordon model, which can be exactly described through an N-body model of Calogero type. The two theories coin

Lixin Xu, Wenbo Li, Jianbo Lu, Baorong Chang

In this paper, a holographic dark energy model, dubbed Ricci dark energy, is confronted with cosmological observational data from type Ia supernovae (SN Ia), baryon acoustic oscillations (BAO) and cosmic microwave background (CMB). By using maximum likelihood method, it is found out that Ricci dark energy model is a viable candidate of dark energy model with

A. A. Clerk, M. H. Devoret, S. M. Girvin, F. Marquardt

The topic of quantum noise has become extremely timely due to the rise of quantum information physics and the resulting interchange of ideas between the condensed matter and AMO/quantum optics communities. This review gives a pedagogical introduction to the physics of quantum noise and its connections to quantum measurement and quantum amplification. After i

Ilya Kapovich, Tatiana Nagnibeda

A \emph{geodesic current} on a free group $F$ is an $F$-invariant measure on the set $\partial^2 F$ of pairs of distinct points of $\partial F$. The space of geodesic currents on $F$ is a natural companion of Culler-Vogtmann's Outer space $cv(F)$ and studying them together yields new information about both spaces as well as about the group $Out(F)$. The

Brooke Feigon, David Whitehouse

We use the relative trace formula to obtain exact formulas for central values of certain twisted quadratic base change L-functions averaged over Hilbert modular forms of a fixed weight and level. We apply these formulas to the subconvexity problem for these L-functions. We also establish an equidistribution result for the Hecke eigenvalues weighted by these

W. Krzemien, I. Frohlich, M. Kajetanowicz, K. Korcyl

The TRB hardware module is a multi-purpose Trigger and Readout Board with on-board DAQ functionality developed for the upgrade of the HADES experiment. It contains a single computer chip (Etrax) running Linux as a well as a 100 Mbit/s Ethernet interface. It has been orginally designed to work as a 128-channel Time to Digital Converter based on the HPTDC chip

M. Ibison

An obstacle to the development of direct action version of electromagnetism was that in the end it failed to fulfill its initial promise of avoiding the problem of infinite Coulomb self-energy in the Maxwell theory of the classical point charge. This paper suggests a small but significant modification of the traditional direct action theory which overcomes t

James A. Blackburn, Jeffrey E. Marchese, Matteo Cirillo, Niels Grønbech-Jensen

An electrical circuit consisting of two capacitively coupled inductive loops, each interrupted by a Josephson junction, is analyzed through the classical RSCJ model. The same circuit has recently been studied experimentally and the results were used to demonstrate quantum mechanical entanglement in the system by observing the correlated states of the two ind

I. V. Biktasheva, D. Barkley, V. N. Biktashev, G. V. Bordyugov

Rotating spiral waves are a form of self-organization observed in spatially extended systems of physical, chemical, and biological nature. A small perturbation causes gradual change in spatial location of spiral's rotation center and frequency, i.e. drift. The response functions (RFs) of a spiral wave are the eigenfunctions of the adjoint linearized oper

G. Catelani, James P. Sethna

We study the metastability of the superheated Meissner state in type II superconductors with k >> 1 beyond Ginzburg-Landau theory, which is applicable only in the vicinity of the critical temperature. Within Eilenberger's semiclassical approximation, we use the local electrodynamic response of the superconductor to derive a generalized thermodynamic pote

Volker D. Burkert

An overview of the CLAS12 detector is presented and the initial physics program after the energy-doubling of the Jefferson Lab electron accelerator. Construction of the 12 GeV upgrade project has started October 2008. A broad program has been developed to map the nucleon's 3-dimensional spin and flavor content through the measurement of deeply exclusive