April 2008 arXiv papers — page 29

Henny J. G. L. M. Lamers

The analysis of the age distributions of star cluster samples of different galaxies has resulted in two very different empirical models for the dissolution of star clusters: the Baltimore model and the Utrecht model. I describe these two models and their differences. The Baltimore model implies that the dissolution of star clusters is mass independent and th

F. K. Roepke

The application of Type Ia supernovae (SNe Ia) as distance indicators in cosmology calls for a sound understanding of these objects. Recent years have seen a brisk development of astrophysical models which explain SNe Ia as thermonuclear explosions of white dwarf stars. While the evolution of the progenitor is still uncertain, the explosion mechanism certain

John Gough

We derive the Hamiltonian associated to a quantum stochastic flow by extending the Albeverio-Kurasov construction of self-adjoint extensions to finite rank perturbations of nonsemibounded operators to Fock space.

Josefina Montalban, Yveline Lebreton, Andrea Miglio, Richard Scuflaire

This contribution is not about the quality of the agreement between stellar models computed by CESAM and CLES codes, but more interesting, on what ESTA-Task~1 run has taught us about these codes and about the input physics they use. We also quantify the effects of different implementations of the same physics on the seismic properties of the stellar models,

Valerio D'Elia, Fabrizio Fiore, Smita Mathur, Filomena Cocchia

We present a detailed analysis of the overdensity of X-ray sources colse to the 3C 295 galaxy cluster (z=0.46) to assess whether it is associated with a filament of the large-scale structure of the Universe. We obtained optical spectra of the optical counterparts of eleven sources associated with the filament, finding that one is at z=0.474. This is a type 1

Jes Madsen

Electron-positron pair creation in supercritical electric fields limits the net charge of any static, spherical object, such as superheavy nuclei, strangelets, and Q-balls, or compact stars like neutron stars, quark stars, and black holes. For radii between $4\times10^2$ fm and $10^4$ fm the upper bound on the net charge is given by the universal relation $Z

J. Lember, A. Koloydenko

Since the early days of digital communication, hidden Markov models (HMMs) have now been also routinely used in speech recognition, processing of natural languages, images, and in bioinformatics. In an HMM $(X_i,Y_i)_{i\ge 1}$, observations $X_1,X_2,...$ are assumed to be conditionally independent given an ``explanatory'' Markov process $Y_1,Y_2,...$

Carlos P. Herrero

Kinetically-grown self-avoiding walks have been studied on Watts-Strogatz small-world networks, rewired from a two-dimensional square lattice. The maximum length L of this kind of walks is limited in regular lattices by an attrition effect, which gives finite values for its mean value < L >. For random networks, this mean attrition length < L > scales as a p

Tien Tjuen Ng, Darwin Gosal, Antia Lamas-Linares, Christian Kurtsiefer

A bulk-optics, polarization-independent phase shifter for photonic quantum information applications is demonstrated. A transverse mode electro-optic modulator using lithium niobate is placed in a Sagnac-like loop containing Faraday rotators. This direction-dependent polarization rotation in the loop is combined with a Mach-Zehnder interferometer to form an o

Gennadiy Averkov

Let P be an elementary closed semi-algebraic set in R^d, i.e., there exist real polynomials p_1,...,p_s such that P= \{x \in R^d : p_1(x) \ge 0, >..., p_s(x) \ge 0 \}; in this case p_1,...,p_s are said to represent P. Denote by $n$ the maximal number of the polynomials from \{p_1,...,p_s\} that vanish in a point of P. If P is non-empty and bounded, we show t

Michel Gross, Michael Atlan, Emilie Absil

We have compared the respective efficiencies of off-axis and phase-shifting holography in terms of noise and aliases removal. The comparison is made by analyzing holograms of an USAF target backlit with laser illumination, recorded with a charge-coupled device camera. We show that it is essential to remove the LO beam noise, especially at low illumination le

Johann Davidov, Gueo Grantcharov, Oleg Mushkarov

The purpose of this article is to review some recent results on the geometry of neutral signature metrics in dimension four and their twistor spaces. The following topics are considered: Neutral Kähler and hyperkähler surfaces, Walker metrics, Neutral anti-self-dual 4-manifolds and projective structures, Twistor spaces of neutral metrics.

Yaroslav V. Bazaikin, Eugene G. Malkovich

We construct complete noncompact Riemannian metrics with $G_2$-holonomy on noncompact orbifolds that are $\Bbb R^3$-bundles with the twistor space $\mathcal{Z}$ as a spherical fiber.

Th. Voigtmann, J. Horbach

The high-pressure dynamics of a computer-modeled silica melt is studied in the framework of the mode-coupling theory of the glass transition (MCT) using static-structure input from molecular-dynamics (MD) computer simulation. The theory reproduces the experimentally known viscosity minimum (diffusivity maximum) as a function of density or pressure and explai

Max Lesaffre, Michael Atlan, Michel Gross

We report the first observation of the dependence of the coherent-backscattering (CBS) enhanced cone with the frequency of the backscattered photon. The experiment is performed on a diffusing liquid suspension and the Doppler broadening of light is induced by the Brownian motion of the scatterers. Heterodyne detection on a CCD camera is used to measure the c

Lu Guo, J. A. Maruhn, P. -G. Reinhard, Y. Hashimoto

We discuss the conservation of angular momentum in nuclear time-dependent Hartree-Fock calculations for a numerical representation of wave functions and potentials on a three-dimensional cartesian grid. Free rotation of a deformed nucleus performs extremely well even for relatively coarse spatial grids. Heavy ion collisions produce a highly excited compound

Michel Gross, Philippe Goy, Mohamed Al-Koussa

We propose a new detection method for ultrasound-modulated optical tomography that allows us to perform parallel speckle detection with optimum shot-noise sensitivity, using a CCD camera. Moreover, we show that making use of a spatial filter system allows us to fully filter out speckle decorrelation noise. This method is confirmed by a test experiment

Yiannis N. Petridis, Morten S. Risager

For a cocompact group $\G$ of $\slr$ we fix a real non-zero harmonic 1-form $α$. We study the asymptotics of the hyperbolic lattice-counting problem for $\G$ under restrictions imposed by the modular symbols $\modsymγ{\a}$. We prove that the normalized values of the modular symbols, when ordered according to this counting, have a Gaussian distribution.

Vincent Koziarz, Ngaiming Mok

In this article we prove first of all the nonexistence of holomorphic submersions other than covering maps between compact quotients of complex unit balls, with a proof that works equally well in a more general equivariant setting. For a non-equidimensional surjective holomorphic map between compact ball quotients, our method applies to show that the set of

R. F. Efendiev

The inverse problem for the Sturm- Liouville operator with complex periodic potential and positive discontinuous coefficients on the axis is studied. Main characteristics of the fundamental solutions are investigated, the spectrum of the operator is studied. We give formulation of the inverse problem, prove a uniqueness theorem and provide a constructive pro

Gino Hrkac, Julian Dean, Alexander Goncharov, Simon Bance

In this paper we numerically conduct micromagnetic modelling to optimize computational boundaries of magnetic thin-film elements applicable to single and double point contact spin torque nano-oscillators. Different boundary conditions have been introduced to compensate spin waves reflections at boundaries that are based on extended layers, absorbing boundari

Julie Gayon, Eric Bois

Multi-planet systems detected until now are in most cases characterized by hot-Jupiters close to their central star as well as high eccentricities. As a consequence, from a dynamical point of view, compact multi-planetary systems form a variety of the general N-body problem (with N >= 3), whose solutions are not necessarily known. Extrasolar planets are up t

T. Shcherbina

We consider the deformed Gaussian Ensemble $H_n=M_n+H^{(0)}_n$ in which $H_n^{(0)}$ is a diagonal Hermitian matrix and $M_n$ is the Gaussian Unitary Ensemble (GUE) random matrix. Assuming that the Normalized Counting Measure of $H_n^{(0)}$ (both non-random and random) converges weakly to a measure $N^{(0)}$ with a bounded support we prove universality of the

C. Yang

We study the isospectral deformations of the Eguchi-Hanson spaces along a torus isometric action in the noncompact noncommutative geometry. We concentrate on locality, smoothness and summability conditions of the nonunital spectral triples, and relate them to the geometric conditions to be noncommutative spin manifolds.

P. Salomé, F. Combes, Y. Revaz, A. C. Edge

We have recently detected CO lines in the well-known filaments around NGC 1275, the galaxy at the centre of the Perseus cluster of galaxies. These previous observations, with the HERA multi-beam array at the IRAM 30m telescope enabled us to make a large map of the CO(2-1) line and to see hints of molecular gas far away from the cluster centre. To confirm the

Yossi Azar, Iftah Gamzu, Shai Gutner

In this paper, we focus our attention on the large capacities unsplittable flow problem in a game theoretic setting. In this setting, there are selfish agents, which control some of the requests characteristics, and may be dishonest about them. It is worth noting that in game theoretic settings many standard techniques, such as randomized rounding, violate c

A. Badertscher, T. Hasegawa, T. Kobayashi, A. Marchionni

In this paper, we consider the physics performance of a single far detector composed of a 100 kton next generation Liquid Argon Time Projection Chamber (LAr TPC) possibly located at shallow depth, coupled to the J-PARC neutrino beam facility with a realistic 1.66 MW operation of the Main Ring. The new far detector could be located in the region of Okinoshima

Irinel Caprini

We investigate the determination of the pole associated to $σ$ from $ππ$ scattering data below the $K\bar{K}$ threshold, including the new precise data from $K_{e4}$ decay reported recently by the NA48/2 Collaboration. Using a large class of analytic parametrizations based on expansions in powers of conformal variables, we obtain for the mass and width of $σ

R. Dodson

We investigate class II methanol masers and the environment in which they form with the Long Baseline Array (LBA). Using full polarisation VLBI, we&#39;re able to measure the magnetic field directions so as to distinguish between the two main models of the environment in which methanol masers form: disks or shocks. We present polarised images of the methanol

Ioannis Deligiannis, Theocharis A. Apostolatos

Proper tuning of the orbital characteristics of the three spacecrafts that constitute the usual triangular configuration of the space-borne gravitational-wave detector LISA, could minimize the breathing mode of its arm-lengths. Since the three spacecrafts form three pairs of interferometric arms, we have the freedom to minimize whichever combination of arm-l

D. N. H. Nam, H. S. Hong, N. V. Khien, N. V. Dai

Magnetic and transport properties of La0.7Ca0.3Mn1-xM&#39;xO3 (M&#39;=Al,Ti) are studied. The dilution of the Mn lattice results in a weakening of the ferromagnetism, a deterioration of the metallic conductivity, and a strong enhancement of the magnetoresistance. Although Tc linearly decreases with x in the low substitution ranges for both M&#39; series, the

Viatcheslav V. Berejnov

Proteins dissolved in a drop induce and enhance the pinning of the drop contact line. This effect dramatically increases volume of drops that are vertically pinned on a flat siliconized substrate. The drop pinning behavior exhibits two regimes: for low protein content in a drop the pinning increases as the contact angle hysteresis increases, and for high pro

A. Bazylak, V. Berejnov, B. Markicevic, D. Sinton

Pore network modelling has traditionally been used to study displacement processes in idealized porous media related to geological flows, with applications ranging from groundwater hydrology to enhanced oil recovery. Very recently, pore network modelling has been applied to model the gas diffusion layer (GDL) of a polymer electrolyte membrane (PEM) fuel cell

Jason D. Hartline, Tim Roughgarden

Mechanism design is now a standard tool in computer science for aligning the incentives of self-interested agents with the objectives of a system designer. There is, however, a fundamental disconnect between the traditional application domains of mechanism design (such as auctions) and those arising in computer science (such as networks): while monetary tran

Vincent Bouchard, Ron Donagi

The constraints imposed on heterotic compactifications by global consistency and phenomenology seem to be very finely balanced. We show that weakening these constraints, as was proposed in some recent works, is likely to lead to frivolous results. In particular, we construct an infinite set of such frivolous models having precisely the massless spectrum of t

Paul Tarau, Brenda Luderman

Logic Programming languages and combinational circuit synthesis tools share a common &#34;combinatorial search over logic formulae&#34; background. This paper attempts to reconnect the two fields with a fresh look at Prolog encodings for the combinatorial objects involved in circuit synthesis. While benefiting from Prolog&#39;s fast unification algorithm and

L. M. Hobbs, D. G. York, T. P. Snow, T. Oka

Echelle spectra of the double-lined spectroscopic binary HD 204827 were obtained on five nights, at a resolving power R = 38,000 and with a S/N ratio = 750 near 6000 A in the final, combined spectrum. The stars show E(B-V) = 1.11 and spectral types near O9.5V and B0.5III. A catalog is presented of 380 diffuse interstellar bands (DIBs) measured between 3900 a

R. L. Dragomirova, L. P. Zarbo, B. K. Nikolic

Injection of unpolarized charge current through the longitudinal leads of a four-terminal two-dimensional electron gas with the Rashba spin-orbit (SO) coupling and/or SO scattering off extrinsic impurities is responsible not only for the pure spin Hall current in the transverse leads, but also for random time-dependent current fluctuations. We employ the sca

Dmitry B. Rokhlin

Let $C$ be a closed convex cone in a Banach ideal space $X$ on a measurable space with a $σ$-finite measure. We prove that conditions $C\cap X_+=\{0\}$ and $C\supset -X_+$ imply the existence of a strictly positive continuous functional on $X$, whose restriction to $C$ is non-positive.

K. Belotsky, A. Galper, B. Luchkov

Statistically significant correlation between positions of unidentified gamma-ray sources (UGS) and the regions of star formation (RSF) is found. Fraction of UGS, coincided in position with RSF, makes up $47\pm 8$%. The coincided discrete gamma-ray sources possess, on average, harder energetic spectra and larger intensities with respect to the rest UGS. Anni

Daniel Juteau

By the geometric Satake isomorphism of Mirkovic and Vilonen, decomposition numbers for reductive groups can be interpreted as decomposition numbers for equivariant perverse sheaves on the complex affine Grassmannian of the Langlands dual group. Using a description of the minimal degenerations of the affine Grassmannian obtained by Malkin, Ostrik and Vybornov

Arlin Crotts, David Yourdon

We report on the discovery of the geometry producing the light echo emanating from Supernova 2006X, a nearby but underluminous Type Ia in M100 (= NGC 4321). This offers a rare chance to study the environment of a Type Ia supernova. Contrary to previous reports, there is little evidence of a circumstellar component in the light echo morphology or in the light

Timothy C. Beers, Daniela Carollo

We report on efforts to identify large samples of very and extremely metal-poor stars based on medium-resolution spectroscopy and ugriz photometry obtained during the course of the Sloan Digital Sky Survey (SDSS), and its extension, SDSS-II, which includes the program SEGUE: Sloan Extension for Galactic Understanding and Exploration. To date, over 8000 stars

James S. Milne, Junecue Suh

We show that conjugation by an automorphism of the complex numbers (as an abstract field) may change the topological fundamental group of a locally symmetric variety over C. As a consequence, we obtain a large class of algebraic varieties defined over number fields with the property that different embeddings of the number field into C give complex varieties

The BABAR Collaboration, B. Aubert

We report on an improved measurement of the Cabibbo-Kobayashi-Maskawa {\it CP}-violating phase $γ$ through a Dalitz plot analysis of neutral $D$ meson decays to $K_S^0 π^+ π^-$ and $K_S^0 K^+ K^-$ in the processes $B^\mp \to D K^\mp$, $B^\mp \to D^* K^\mp$ with $D^* \to Dπ^0,Dγ$, and $B^\mp \to D K^{*\mp}$ with $K^{*\mp} \to K_S^0 π^\mp$. Using a sample of 3

Zurab Berezhiani

It was pointed out recently that oscillation of the neutron $n$ into mirror neutron $n&#39;$, a sterile twin of the neutron with exactly the same mass, could be a very fast process with the the baryon number violation, even faster than the neutron decay itself. This process is sensitive to the magnetic fields and it could be observed by comparing the neutron

J. Manuel Garcia-Islas

We present a microscopical explanation of the entropy of the BTZ black hole using discrete spin foam models of quantum gravity. The entropy of a black hole is given in geometrical terms which lead us to think that its statistical description must be given in terms of a quantum geometry. In this paper we present it in terms of spin foam geometrical observable

R. V. Gorbachev, A. S. Mayorov, A. K. Savchenko, D. W. Horsell

We have fabricated graphene devices with a top gate separated from the graphene layer by an air gap--a design which does not decrease the mobility of charge carriers under the gate. This gate is used to realise p-n-p structures where the conducting properties of chiral carriers are studied. The band profile of the structures is calculated taking into account

Eric Bedford, Kyounghee Kim

We construct k-parameter families of rational surface automorphisms for any k. These are automorphisms of surfaces X, which are constructed from iterated blowups over the projective plane. In certain cases: we are able to determine the exact automorphism group of X, as well as when two of the surfaces X are inequivalent.

Narendra Sahu, Utpal Sarkar

We propose an extension of the standard model with a $U(1)_{\rm B-L}$ global symmetry that accommodates radiative neutrino masses along with dark matter and leptogenesis. The observed matter antimatter asymmetry of the universe is generated through the leptogenesis route keeping the $U(1)_{\rm B-L}$ symmetry intact. The $B-L$ global symmetry is then softly b

Luis A. Anchordoqui, Haim Goldberg, Satoshi Nawata, Tomasz R. Taylor

The LHC program will include the identification of events with single prompt high-k_\perp photons as probes of new physics. We show that this channel is uniquely suited to search for experimental evidence of TeV-scale open string theory. At the parton level, we analyze single photon production in gluon fusion, gg \to γg, with open string states propagating i

Leonid Makar-Limanov, Umut Turusbekova, Ualbai Umirbaev

We describe the automorphism groups of elliptic Poisson algebras on polynomial algebras in three variables and give an explicit set of generators and defining relations for this group.

M. Rosenkranz, D. Jaksch, F. Y. Lim, W. Bao

We observe a sudden breakdown of the transport of a strongly repulsive Bose-Einstein condensate through a shallow optical lattice of finite width. We are able to attribute this behavior to the development of a self-trapped state by using accurate numerical methods and an analytical description in terms of nonlinear Bloch waves. The dependence of the breakdow

P. Banerjee, R. Chatterjee, R. Shyam

We calculate the Coulomb dissociation of 9Li on Pb and U targets at 28.5 MeV/A beam energy within a finite range distorted wave Born approximation formalism of the breakup reactions. Invoking the principle of detailed balance, these cross sections are used to determine the excitation function and subsequently the rate of the radiative capture reaction 8Li(n,

Sergio Arianos, Anna Carbone

A method for estimating the cross-correlation $C_{xy}(τ)$ of long-range correlated series $x(t)$ and $y(t)$, at varying lags $τ$ and scales $n$, is proposed. For fractional Brownian motions with Hurst exponents $H_1$ and $H_2$, the asymptotic expression of $C_{xy}(τ)$ depends only on the lag $τ$ (wide-sense stationarity) and scales as a power of $n$ with exp

Belle Collaboration, Y. Horii, K. Trabelsi, H. Yamamoto

We report a study of the suppressed B meson decay B^- -> D K^- followed by D -> K^+ π^-, where D indicates a D^0 or \bar{D}^0 state. The two decay paths interfere and provide information on the CP-violating angle ϕ_3. We use a data sample containing 657 x 10^6 B\bar{B} pairs recorded at the Υ(4S) resonance with the Belle detector at the KEKB asymmetric-energ

M. Ahsan Zeb, K. Sabeeh, M. Tahir

Chiral tunneling through a harmonically driven potential barrier in graphene monolayer is considered in this work. Since the quasiparticles in this system are chiral in nature, tunneling is highly anisotropic, we determine the transmission probabilities for the central and sidebands as the incident angle of the electron beam is changed . Furthermore, we inve

Wlodzimierz Jelonek

The aim of this paper is to describe a large class of Hermitian Gray manifolds.

Yoav Achiman

The minimal renormalizable SUSY SO(10) model is a very compact and predictive theory. It was very popular till one realized that it cannot account for the masses of the neutrinos. The best cure to this problem is to add the 120 Higgs representaion, the &#39;next to minimal&#39; version. To reduce the number of free parameters, it was suggested in recent pape

Zhi-An Ren, Wei Lu, Jie Yang, Wei Yi

Here we report the superconductivity in the iron-based oxyarsenide Sm[O1-xFx]FeAs, with the onset resistivity transition temperature at 55.0 K and Meissner transition at 54.6 K. This compound has the same crystal structure as LaOFeAs with shrunk crystal lattices, and becomes the superconductor with the highest critical temperature among all materials besides

Roman Linares, Hugo A. Morales-Tecotl, Omar Pedraza

Vacuum force is an interesting low energy test for brane worlds due to its dependence on field&#39;s modes and its role in submillimeter gravity experiments. In this work we generalize a previous model example: the scalar field vacuum force between two parallel plates lying in the brane of a Randall-Sundrum scenario extended by $p$ compact dimensions (RSII-$

Lung-Chi Chen, Akira Sakai

We prove that the Fourier transform of the properly-scaled normalized two-point function for sufficiently spread-out long-range oriented percolation with index α>0 converges to e^{-C|k|^{α\wedge2}} for some C\in(0,\infty) above the upper-critical dimension 2(α\wedge2). This answers the open question remained in the previous paper [arXiv:math/0703455]. Moreov

Xusheng Zhang, Zhi-Feng Huang, Jorge Viñals

Twist grain boundaries are widely observed in lamellar phases of block copolymers. A mesoscopic model of the copolymer is used to obtain stationary configurations that include a twist grain boundary, and to analyze their stability against long wavelength perturbations. The analysis presented is valid in the weak segregation regime, and includes direct numeri

P. Bicudo

The possible production processes of the antiK-NN are explored. We derive microscopically, with the RGM, the microscopic derivation of the K-N and antiK-N interactions. We discuss the binding or not binding of the different antiK-N and antiK-NN systems. When binding occurs, the respective decay widths are also discussed.

B. J. Overbosch, Xiao-Gang Wen

Starting from the edge reconstructed Pfaffian state and the anti-Pfaffian state for the filling fraction $ν={5/2}$ fractional quantum Hall (FQH) state with the filled Landau levels included, we find that interactions between counterpropagating edge modes can induce phase transitions on the edge. In the new `Majorana-gapped&#39; phases, a pair of counter prop

P. D. Smith, J. I. Sakai

Aims: To investigate magnetic reconnection rates during the coalescence of two current loops in the solar chromosphere, by altering the neutral-hydrogen to proton density ratio, ioniziation/recombination coefficients, collision frequency and relative helicity of the loops. Methods: 2.5D numerical simulations of the chromosphere were conducted using a newly d

Grzegorz Bobinski

Let A be a tame quasi-tilted algebra and d the dimension vector of an indecomposable A-module. In the paper we prove that each irreducible component of the variety of A-modules of dimension vector d is regular in codimension one.

Alexander Sevrin, Wieland Staessens, Alexander Wijns

We present a manifestly supersymmetric description of A and B branes on Kaehler manifolds using a completely local N=2 superspace formulation of the world-sheet nonlinear sigma-model in the presence of a boundary. In particular, we show that an N=2 superspace description of type A boundaries is possible. This leads to a concrete realization of the still poor

M. W. C. Dharma-Wardana

Simple analytic formulae for energy relaxation (ER) in electron-ion systems, with quantum corrections, ion dynamics and RPA-type screening are presented. ER in the presence of bound electrons is examined in view of of recent simulations for ER in hydrogen in the range 10^{20}-10^{24} electrons/cc.

Mikhail Khovanov, Aaron D. Lauda

We categorify one-half of the quantum group associated to an arbitrary Cartan datum.

Robert B. Mann, Donald Marolf, Robert McNees, Amitabh Virmani

The recent introduction of a boundary stress tensor for asymptotically flat spacetimes enabled a new construction of energy, momentum, and Lorentz charges. These charges are known to generate the asymptotic symmetries of the theory, but their explicit formulas are not identical to previous constructions in the literature. This paper corrects an earlier compa

M. R. Tarbutt, E. A. Hinds

Neutral particles can be guided and focussed using electric field gradients that focus in one transverse direction and defocus in the other, alternating between the two directions. Such a guide is suitable for transporting particles that are attracted to strong electric fields, which cannot be guided using static fields. Particles are only transmitted if the

Tsvi Piran

Bohdan Paczy&#39;nski was one of the pioneers of the cosmological GRB model. His ideas on how GRBs operate and what are their progenitors have dominated the field of GRBs in the hectic nineties during which the distances and the origin of GRBs were revealed. I discuss here Bohdan&#39;s contributions in some historical perspective.

Aaron Magid

We provide an infinite family of pared manifolds whose relative deformation spaces of hyperbolic structures on these manifolds are not locally connected. This is a natural extension of the recent result of Bromberg that shows the space of Kleinian punctured torus groups is not locally connected.

S. G. Alves, S. C. Ferreira, M. L. Martins

We review some computer algorithms for the simulation of off-lattice clusters grown from a seed, with emphasis on the diffusion-limited aggregation, ballistic aggregation and Eden models. Only those methods which can be immediately extended to distinct off-lattice aggregation processes are discussed. The computer efficiencies of the distinct algorithms are c

Yuri Lyubarsky

Effect of the induced Compton and Raman scattering on short, bright radio pulses is investigated. It is shown that when a single pulse propagates through the scattering medium, the effective optical depth is determined by the duration of the pulse but not by the scale of the medium. The induced scattering could hinder propagation of the radio pulse only if c

Paolo Luchini

The commonly accepted description of transition to turbulence in shear flows requires the presence of an external source of disturbances that get amplified by an essentially linear mechanism up to the point where breakdown to turbulence occurs. Microscopic fluctuations are shown here to provide just the right amount of initial disturbances to match the predi

Prasanta Pal, Corey S. O&#39;Hern, Jerzy Blawzdziewicz, Robin Stinchcombe

To elucidate slow dynamics in glassy materials, we introduce the {\it Figure-8 model} in which $N$ hard blocks undergo Brownian motion around a circuit in the shape of a figure-8. This system undergoes kinetic arrest at a critical packing fraction $ϕ=ϕ_g < 1$, and for $ϕ\approxϕ_g$ long-time diffusion is controlled by rare, cooperative `junction-crossing&#39

Zhang Shengli, Soung chang Liew, Lu Lu

Direct application of network coding at the physical layer - physical layer network coding (PNC) - is a promising technique for two-way relay wireless networks. In a two-way relay network, relay nodes are used to relay two-way information flows between pairs of end nodes. This paper proposes a precise definition for PNC. Specifically, in PNC, a relay node do

José R. Pérez-Agüera, Lourdes Araujo

Query expansion is a well known method to improve the performance of information retrieval systems. In this work we have tested different approaches to extract the candidate query terms from the top ranked documents returned by the first-pass retrieval. One of them is the cooccurrence approach, based on measures of cooccurrence of the candidate and the query

M. Bier, F. J. Cao

Fueled by the hydrolysis of ATP, the motor protein kinesin literally walks on two legs along the biopolymer microtubule. The number of accidental backsteps that kinesin takes appears to be much larger than what one would expect given the amount of free energy that ATP hydrolysis makes available. This is puzzling as more than a billion years of natural select

Akinbo Ojo

If a photon fluctuates from &#39;nothing&#39;, what would it look like and how would it behave? Here we examine such a photon and the possible characteristics and effects it may have. If contrary to theoretical expectation, it is not short-lived, we find quantitative and qualitative similarities with the quantitative and qualitative features of the standard

Emily Burgunder

Kontsevich has proven that the Lie homology of the Lie algebra of symplectic vector fields can be computed in terms of the homology of a graph complex. We prove that the Leibniz homology of this Lie algebra can be computed in terms of the homology of a variant of the graph complex endowed with an action of the symmetric groups. The resulting isomorphism is s

Mark J. Everitt, Shaaban Khalil, Alexandre M. Zagoskin

A series of recent papers ``Faster than Hermitian Quantum Mechanics&#39;&#39; and related articles made a point of the possibility of a non-Hermitian, but PT-symmetric, operator to play the role of a Hamiltonian. In particular, they show that with an appropriate choice of an inner product, the evolution generated by such an operator will conserve the norm an

Antonio Galves, Eva Löcherbach

Stochastic chains with memory of variable length constitute an interesting family of stochastic chains of infinite order on a finite alphabet. The idea is that for each past, only a finite suffix of the past, called context, is enough to predict the next symbol. These models were first introduced in the information theory literature by Rissanen (1983) as a u

N. I. Sandu

It is known that with precision till isomorphism that only and only loops $M(F) = M_0(F)/<-1>$, where $M_0(F)$ denotes the loop, consisting from elements of all matrix Cayley-Dickson algebra $C(F)$ with norm 1, and $F$ be a subfield of arbitrary fixed algebraically closed field, are simple non-associative Moufang loops. In this paper it is proved that the si

N. I. Sandu

Let $C(F)$ be a matrix Cayley-Dickson algebra over field $F$. By $M_0(F)$ we denote the loop containing of all elements of algebra $C(F)$ with norm 1. It is shown in this paper that with precision till isomorphism the loops $M_0(F)/<-1>$ they and only they are simple non-associative Moufang loops, where $F$ are subfields of algebraic closed field

Christopher G. Timpson

The Bayesian approach to quantum mechanics of Caves, Fuchs and Schack is presented. Its conjunction of realism about physics along with anti-realism about much of the structure of quantum theory is elaborated; and the position defended from common objections: that it is solipsist; that it is too instrumentalist; that it cannot deal with Wigner&#39;s friend s

Jan Gersl

The Bousso entropy bound is investigated for static spherically symmetric configurations of ideal gas with Bose-Einstein and Fermi-Dirac distribution function. Gas of massive particles is considered. The paper is continuation of the previous work concerning the massless case. Special attention is devoted to lightsheets generated by spheres. Conditions under

Masashi Hayakawa, Shunpei Uno

On account of its application to the present and future analysis of the virtual photon correction to the hadronic properties by means of lattice QCD simulation, we initiate the study of the finite size scaling effect on the QED correction using low energy effective theory of QCD with QED. For this purpose, we begin with formulating a new QED on the space wit

Tingrong Lu

In Kleinrock and Kamoun&#39;s paper, the inverse relation of routing table length index and routing path length index in hierarchical routing model is illustrated. In this paper we give the analytical correlation of routing table length index and routing path length index in hierarchical routing model.

B. Huard, N. Stander, J. A. Sulpizio, D. Goldhaber-Gordon

We perform electrical transport measurements in graphene with several sample geometries. In particular, we design ``invasive&#39;&#39; probes crossing the whole graphene sheet as well as ``external&#39;&#39; probes connected through graphene side arms. The four-probe conductance measured between external probes varies linearly with charge density and is symm

Alexander Berkovich, Hamza Yesilyurt

In this paper we derive an explicit formula for the number of representations of an integer by the sextenary form x^2+y^2+z^2+ 7s^2+7t^2+ 7u^2. We establish the following intriguing inequalities 2b(n)>=a_7(n)>=b(n) for n not equal to 0,2,6,16. Here a_7(n) is the number of partitions of n that are 7-cores and b(n) is the number of representations of n+2 by th

Serban E. Vlad

The asynchronous systems are the models of the asynchronous circuits from the digital electrical engineering. An asynchronous system f is a multi-valued function that assigns to each admissible input u a set f(u) of possible states x in f(u). A special case of asynchronous system consists in the existence of a Boolean function Υsuch that for any u and any x

Andrew Adamatzky

Plasmodium of Physarym polycephalum is an ideal biological substrate for implementing concurrent and parallel computation, including combinatorial geometry and optimization on graphs. We report results of scoping experiments on Physarum computing in conditions of minimal friction, on the water surface. We show that plasmodium of Physarum is capable for compu

Christian Eder

Faugere&#39;s F5 algorithm is one of the fastest known algorithms for the computation of Grobner bases. So far only the F5 Criterion is proved, whereas the second powerful criterion, the Rewritten Criterion, is not understood very well until now. We give a proof of both, the F5 Criterion and the Rewritten Criterion showing their connection to syzygies, i.e.

M. Marvan

We consider the problem whether a nonparametric zero-curvature representation can be embedded into a one-parameter family within the same Lie algebra. After introducing a computable cohomological obstruction, a method using the recursion operator to incorporate the parameter is discussed.

A. De Castro, I. Martin, L. Quevedo, A. Restuccia

We define a noncommutative and nonanticommutative associative product for general supersymplectic forms, allowing the explicit treatment of non(anti)commutative field theories from general nonconstant string backgrounds like a graviphoton field. We propose a generalization of deformation quantization a la Fedosov to superspace, which considers noncommutativi

S. Towers

This case study of a typical U.S. particle physics experiment explores the issues of gender bias and how it affects the academic career advancement prospects of women in the field of physics beyond the postdoctoral level; we use public databases to study the career paths of the full cohort of 57 former postdoctoral researchers on the Run II Dzero experiment

D. V. Vassilevich

We consider quantum corrections to a kink of noncommutative supersymmetric phi^4 theory in 1+1 dimensions. Despite the presence of an infinite number of time derivatives in the action, we are able to define supercharges and a Hamiltonian by using an unconventional canonical formalism. We calculate the quantum energy E of the kink (defined as a half-sum of th