February 2013 arXiv papers — page 3

Paul Jansen, Isabelle Kleiner, Congsen Meng, Ronald M. Lees

Recently, the extremely sensitive torsion-rotation transitions in methanol have been used to set a tight constraint on a possible variation of the proton-to-electron mass ratio over cosmological time scales. In order to improve this constraint, laboratory data of increased accuracy will be required. Here, we explore the possibility for performing high-resolu

Benjamin Favier, Paul J. Bushby

Mean-field dynamo theory suggests that turbulent convection in a rotating layer of electrically-conducting fluid produces a significant alpha-effect, which is one of the key ingredients in any mean-field dynamo model. Provided that this alpha-effect operates more efficiently than (turbulent) magnetic diffusion, such a system should be capable of sustaining a

B M McLaughlin

The success of the R-matrix with pseudo-state (RMPS) method to model single photoionization processes, benchmarked against dedicated synchrotron light source measurements, is exploited and extended to investigate, single photon double ionization cross-sections for the He-like, Li$^+$ ion. We investigate these processes from both the ground state and the exci

L. Lever, Z. Ikonić, A. Valavanis, R. W. Kelsall

We report the observation of the quantum-confined Stark effect in Ge/SiGe multiple quantum well heterostructures grown on Si(0.22)Ge(0.78) virtual substrates. The large compressive strain in the Ge quantum well layers caused by the lattice mismatch with the virtual substrate results in a blue shift of the direct absorption edge, as well as a reduction in the

Pietro Biancofiore

The exclusive radiative $B \to K^* γ$, $B \to K^*_2 γ$, $B_s \to ϕγ$ and $Λ_b \to Λγ$ decays are studied in a new physics scenario with two universal extra dimensions compactified on a chiral square. The computed branching fractions depend on the size $R$ of the extra dimensions, and a comparison with the available measurements allows us to put bounds on suc

Jonathan Breuer, Yoram Last, Barry Simon

We study the stability of convergence of the Christoffel-Darboux kernel, associated with a compactly supported measure, to the sine kernel, under perturbations of the Jacobi coefficients of the measure. We prove stability under variations of the boundary conditions and stability in a weak sense under $\ell^1$ and random $\ell^2$ diagonal perturbations. We al

Hehe Li, Zhigang Bu, Yuee Luo, Wenbo Chen

By means of the optical metric, we investigate the propagation of a polarized light in an inhomogeneous medium in this paper. We find that the evolution of photons is affected by the spin-spin interaction of photons, besides the spin-orbit interaction. Due to the spin-spin interaction, there is a small deflection of the ray trajectory of the polarized light

Denis N. Sidorov

The sufficient conditions are obtained for existence of the main solution of the nonlinear Volterra integral equation of the second kind on the semi-axis and on a finite interval. The method for computation of this boundary interval is designed. Beyond such integral the solution has the blow-up. The efficiency of proposed technique is demonstrated on concret

Norman Gürlebeck

We derive source integrals for multipole moments that describe the behaviour of static and axially symmetric spacetimes close to spatial infinity. We assume isolated non-singular sources but will not restrict the matter content otherwise. Some future applications of these source integrals of the asymptotic multipole moments are outlined as well.

Calvin J. Tabert, Elisabeth J. Nicol

We calculate the finite-frequency conductivity of bilayer graphene with a relative twist between the layers. The low frequency response at zero doping shows a flat conductivity with value twice that of the monolayer case and at higher frequency a strong absorption peak occurs. For finite doping, the low frequency flat absorption is modified into a peak about

Jacob Fox, Janos Pach

An intersection graph of curves in the plane is called a string graph. Matousek almost completely settled a conjecture of the authors by showing that every string graph of m edges admits a vertex separator of size O(\sqrt{m}\log m). In the present note, this bound is combined with a result of the authors, according to which every dense string graph contains

Foz Hughes, Andrew Prudom, Gerry Swallowe

A traditional split-Hopkinson pressure bar system has been modified by the addition of ZK60A magnesium alloy pressure bars in order to increase the resolution of data when examining specimens of low-density, high-density and ultra-high molecular weight polyethylene. It was found that the low density of the ZK60A allowed a decent increase in transmitted pulse

Sudarshan Gurjar

The aim of this paper is to give a proof of the restriction theorems for principal bundles with a reductive algebraic group as structure group in arbitrary characteristic. Let $G$ be a reductive algebraic group over any field $k=\bar{k}$, let $X$ be a smooth projective variety over $k$, let $H$ be a very ample line bundle on $X$ and let $E$ be a semistable (

M. De Giorgi, D. Ballarini, E. Cancellieri, F. M. Marchetti

We investigate the cross-interactions in a two-component polariton quantum fluid coherently driven by two independent pumping lasers tuned at different energies and momenta. We show that both the hysteresis cycles and the ON/OFF threshold of one polariton signal can be entirely controlled by a second polariton fluid. Furthermore, we study the ultrafast switc

Piotr Biler, Cyril Imbert, Grzegorz Karch

A degenerate nonlinear nonlocal evolution equation is considered; it can be understood as a porous medium equation whose pressure law is nonlinear and nonlocal. We show the existence of sign changing weak solutions to the corresponding Cauchy problem. Moreover, we construct explicit compactly supported self-similar solutions which generalize Barenblatt profi

Jinlong Wang, Yu Shi

We consider the ground state of a mixture of two pseudospin-$\1/2$ Bose gases with interspecies spin exchange in a trapping potential. In the mean field approach, the ground state can be described in terms of four wave functions governed by a set of coupled Gross-Pitaevskii-like (GP-like) equations, which differ from the usual GP equations in the existence o

Joe Walmswell, Cathie Clarke, Peter Cossins

We investigate the kinematic evolution of planetesimals in self-gravitating discs, combining Smoothed Particle Hydrodynamical (SPH) simulations of the disc gas with a gravitationally coupled population of test particle planetesimals. We find that at radii of 10s of au (which is where we expect planetesimals to be possibly formed in such discs) the planetesim

Aielet Efrati, Daniel Grossman, Yonit Hochberg

A new boson with mass ~125 GeV and properties similar to the Standard Model Higgs has been discovered by both the ATLAS and CMS collaborations, with significant observation in the ZZ* to 4 leptons and the diphoton channels. In this work we ask whether the signals in these two channels can be due primarily to two distinct resonances, each contributing dominan

Li Ge, Yu Shi

Using the approach of low-energy effective field theory, the phase diagram is studied for a mixture of two species of pseudospin-$\1/2$ Bose atoms with interspecies spin-exchange. There are four mean-field regimes on the parameter plane of $g_e$ and $g_z$, where $g_e$ is the interspecies spin-exchange interaction strength, while $g_z$ is the difference betwe

Milena Pabiniak

Let G be a compact connected Lie group G and T its maximal torus. The coadjoint orbit O_lambda through lambda in Lie(T)^* is canonically a symplectic manifold. Therefore we can ask the question about its Gromov width. In many known cases the Gromov width is exactly the minimum over the set {< alpha_j^{\vee},lambda > ; alpha_j^{\vee} a coroot and < alpha_j^{\

P. Martinez, M. Kasper, A. Costille, J. F. Sauvage

Observing sequences have shown that the major noise source limitation in high-contrast imaging is due to the presence of quasi-static speckles. The timescale on which quasi-static speckles evolve, is determined by various factors, among others mechanical or thermal deformations. Understanding of these time-variable instrumental speckles, and especially their

Marcus Waurick

We discuss $G$-convergence of linear integro-differential-algebaric equations in Hilbert spaces. We show under which assumptions it is generic for the limit equation to exhibit memory effects. Moreover, we investigate which classes of equations are closed under the process of $G$-convergence. The results have applications to the theory of homogenization. As

Mustapha Dehmani, Mohamed Errahmani, Hamid Ez-Zahraouy, Abdelilah Benyoussef

The disturbance effect of a depolarizing channel on the security of the quantum key distribution of the four state BB84 protocol with multiple sequentiel intercept and resend attacks of many eavesdroppers, has been studied. The quantum bit error rate and the mutual information are computed for arbitray number of attacks.

S. S. Aleshin, O. G. Kharlanov, A. E. Lobanov

The Earth&#39;s density distribution can be approximately considered piecewise continuous at the scale of two-flavor oscillations of typical solar neutrinos, such as the beryllium-7 and boron-8 neutrinos. This quite general assumption appears to be enough to analytically calculate the day-night asymmetry factor for such neutrinos. Using the explicit time ave

Simon C. Harris, Matthew I. Roberts

We demonstrate a novel strong law of large numbers for branching processes, with a simple proof via measure-theoretic manipulations and spine theory. Roughly speaking, any sequence of events that eventually occurs almost surely for the spine entails the almost sure convergence of a certain sum over particles in the population.

Zvonko Glumac, Katarina Uzelac

The phase diagram of the two- and three-state Potts model with infinite-range interactions, in the external field is analyzed by studying the partition function zeros in the complex field plane. The tricritical point of the three-state model is observed as the approach of the zeros to the real axis at the nonzero field value. Different regimes, involving sev

Naoya Eguchi, Fumihiro Ishikawa, Michihiro Kodama, Takeshi Wakabayashi

We successfully synthesized new layered iron oxypnictide Sr2CrO2(FeAs)2 by solid-state-reaction techniques. This is the first report on the Fe-substituted Sr2Mn3As2O2-type oxypnictides to our knowledge. A pellet of stoichiometric mixtures of SrO, Cr and FeAs wrapped with tantalum foil was sintered at 900°C for 96 h. Results of x-ray diffraction measurement a

Tian Zhang, Wei Chen, Zhu Han, Zhigang Cao

Cooperative transmission in vehicular networks is studied by using coalitional game and pricing in this paper. There are several vehicles and roadside units (RSUs) in the networks. Each vehicle has a desire to transmit with a certain probability, which represents its data burtiness. The RSUs can enhance the vehicles&#39; transmissions by cooperatively relayi

Eike Mueller, Xu Guo, Robert Scheichl, Sinan Shi

Many problems in geophysical and atmospheric modelling require the fast solution of elliptic partial differential equations (PDEs) in &#34;flat&#34; three dimensional geometries. In particular, an anisotropic elliptic PDE for the pressure correction has to be solved at every time step in the dynamical core of many numerical weather prediction models, and equ

Marcelo Serrano Zanetti, Ingo Scholtes, Claudio Juan Tessone, Frank Schweitzer

Social organization and division of labor crucially influence the performance of collaborative software engineering efforts. In this paper, we provide a quantitative analysis of the relation between social organization and performance in Gentoo, an Open Source community developing a Linux distribution. We study the structure and dynamics of collaborations as

Julia Fang, Jean-Luc Margot

We used a sample of Kepler candidate planets with orbital periods less than 200 days and radii between 1.5 and 30 Earth radii to determine the typical dynamical spacing of neighboring planets. To derive the intrinsic (i.e., free of observational bias) dynamical spacing of neighboring planets, we generated populations of planetary systems following various dy

A. Lebreton, I. Abram, R. Braive, I. Sagnes

Interferometric photon-correlation measurements, which correspond to the second-order intensity cross-correlations between the two output ports of an unbalanced Michelson interferometer, are sensitive to both amplitude and phase fluctuations of an incoming beam of light. Here, we present the theoretical framework behind these measurements and show that they

Katherine Thomas, Stephan Herminghaus, Hubertus Porada, Lucas Goehring

Kinneyia are a class of microbially mediated sedimentary fossils. Characterised by clearly defined ripple structures, Kinneyia are generally found in areas that were formally littoral habitats and covered by microbial mats. To date there has been no conclusive explanation of the processes involved in the formation of these fossils. Microbial mats behave like

Roberto Iuppa

In recent years very important results were obtained from cosmic ray experiments about the arrival direction distribution of primaries in the TeV energy range. As most of these particles are charged nuclei, they are deflected by the magnetic field they pass through before reaching the Earth surface, the effect of the Lorentz force being inversely proportiona

A. Zigler, S. Eisenman, M. Botton, E. Nahum

We experimentally demonstrate a notably enhanced acceleration of protons to high energy by relatively modest ultrashort laser pulses and structured dynamical plasma targets. Realized by special deposition of snow targets on sapphire substrates and using carefully planned pre-pulses, high proton yield emitted in a narrow solid angle with energy above 21MeV we

P. M. Tomchuk, V. M. Bondar, L. S. Solonchuk

Polarization dependences of the terahertz radiation emitted by hot charge carriers in p-Te have been studied both theoretically and experimentally. The angular dependences of the spontaneous radiation emission by hot carriers is shown to originate from the anisotropy of their dispersion law and the anisotropy of the dielectric permittivity of a tellurium cry

L. M. van Haaften, G. Nelemans, R. Voss, S. Toonen

[abridged] Aims. We model the number and properties of ultracompact X-ray binaries (UCXBs) in the Galactic Bulge. The objective is to learn about the formation of UCXBs and their evolution, such as the onset of mass transfer and late-time behavior. Methods. The binary population synthesis code SeBa and stellar evolutionary tracks are used to model the UCXB p

Dong Yi, Zhen Lei, Yang Hu, Stan Z. Li

In this paper, we propose a method to apply the popular cascade classifier into face recognition to improve the computational efficiency while keeping high recognition rate. In large scale face recognition systems, because the probability of feature templates coming from different subjects is very high, most of the matching pairs will be rejected by the earl

F. Da Pieve, S. Di Matteo, T. Rangel, M. Giantomassi

Combining LSDA+$U$ and an analysis of superexchange interactions beyond DFT, we describe the magnetic ground states in rutile and anatase Cr-doped TiO$_2$. In parallel, we correct our LSDA+$U$ ground state through GW corrections ($GW$@LSDA+$U$) that reproduce the position of impurity states and the band gaps in satisfying agreement with experiments. Because

Tianping Ying, Xiaolong Chen, Gang Wang, Shifeng Jin

The ubiquitous coexistence of majority insulating 245 phases and minority superconducting (SC) phases in AxFe2-ySe2 (A = K, Cs, Rb, Tl/Rb, Tl/K) formed by high-temperature routes makes pure SC phases highly desirable for studying the intrinsic properties of this SC family. Here we report that there are at least two pure SC phases, KxFe2Se2(NH3)y (x ~ 0.3 and

N. Sahakyan, R. Yang, F. A. Aharonian, F. M. Rieger

We report on an analysis of \fermi data from four year of observations of the nearby radio galaxy Centaurus A (Cen A). The increased photon statistics results in a detection of high-energy ($>\:100$ MeV) $γ$-rays up to 50 GeV from the core of Cen A, with a detection significance of about 44$σ$. The average gamma-ray spectrum of the core reveals evidence for

Jun-Ho Lee, Yun-Ki Choi, Hyun-Jung Kim, Ralph H. Scheicher

We present a comparative study of DNA nucleobases [guanine (G), adenine (A), thymine (T), and cytosine (C)] adsorbed on hexagonal boron nitride (\textit{h}-BN) sheet and graphene, using local, semilocal, and van der Waals (vdW) energy-corrected density-functional theory (DFT) calculations. Intriguingly, despite the very different electronic properties of BN

J. Danon

We theoretically study the $(1,1)$ triplet to $(0,2)$ singlet relaxation rate in a lateral gate-defined double quantum dot tuned to the regime of Pauli spin blockade. We present a detailed derivation of the effective phonon density of states for this specific charge transition, keeping track of the contribution from piezoelectric as well as deformation poten

Peter beim Graben

In their target article, \citet{WangBusemeyer13} [A quantum question order model supported by empirical tests of an a priori and precise prediction. \emph{Topics in Cognitive Science}] discuss question order effects in terms of incompatible projectors on a Hilbert space. In a similar vein, Blutner recently presented an orthoalgebraic query language essential

Belén López Martí, Francisco Jiménez-Esteban, Amelia Bayo, David Barrado

(abridged) We want to provide further evidence of the origin of the proposed stellar members of Chamaeleon and to identify interlopers from the foreground εCha and ηCha associations. To this aim, we compile lists of spectroscopically confirmed members of Chamaeleon I and II, εCha and ηCha, and of background objects in the same line of sight. Using Virtual Ob

Spase Petkoski, Dmytro Iatsenko, Lasko Basnarkov, Aneta Stefanovska

We investigate interacting phase oscillators whose mean field is at a different frequency from the mean or mode of their natural frequencies. The associated asymmetries lead to a macroscopic travelling wave. We show that the mean ensemble frequency of such systems differs from their entrainment frequency. In some scenarios these frequencies take values that,

F. Da Pieve, P. Krüger

A first principles approach for spin and angle resolved resonant photoemission is developed within multiple scattering theory and applied to a Cr(110) surface at the 2$p$-3$d$ resonance. The resonant photocurrent from this non ferromagnetic system is found to be strongly spin polarized by circularly polarized light, in agreement with experiments on antiferro

Jonathan Touboul, Maciej Krupa, Mathieu Desroches

We investigate the dynamics of large stochastic networks with different timescales and nonlinear mean-field interactions. After deriving the limit equations for a general class of network models, we apply our results to the celebrated Wilson-Cowan system with two populations with or without slow adaptation, paradigmatic example of nonlinear mean-field networ

Klaus G. Puschmann, Carsten Denker, Horst Balthasar, Rohan E. Louis

The GREGOR Fabry-Pérot Interferometer (GFPI) is one of three first-light instruments of the German 1.5-meter GREGOR solar telescope at the Observatorio del Teide, Tenerife, Spain. The GFPI allows fast narrow-band imaging and post-factum image restoration. The retrieved physical parameters will be a fundamental building block for understanding the dynamic Sun

Vieri Benci, Lorenzo Luperi Baglini

Ultrafunctions are a particular class of functions defined on a non-Archimedean field. They provide generalized solutions to functional equations which do not have any solutions among the real functions or the distributions. In this paper we analyze sistematically some basic properties of the spaces of ultrafunctions.

Vincenzo Vitagliano, Jun-Qing Xia, Stefano Liberati, Matteo Viel

Cosmography is the tool that makes possible to untie the interpretation of cosmological observations from the definition of any dynamical prior. We review the constraints on the cosmographic parameter obtained using the most thorough data set ensemble available. We focus on some specific topics about the statistically based selection of the most stringent fi

Raffaella Burioni, Federico Corberi, Alessandro Vezzani

We study phase-ordering dynamics of a ferromagnetic system with a scalar order-parameter on fractal graphs. We propose a scaling approach, inspired by renormalization group ideas, where a crossover between distinct dynamical behaviors is induced by the presence of a length $λ$ associated to the topological properties of the graph. The transition between the

Alessandro Pluchino, Cesare Garofalo, Giuseppe Inturri, Andrea Rapisarda

In order to analyse the behaviour of pedestrians at the very fine scale, while moving along the streets, in open spaces or inside a building, simulation modelling becomes an essential tool. In these spatial environments, in the presence of unusual demand flows, simulation requires the ability to model the local dynamics of individual decision making and beha

J. Maund, E. Reilly, S. Mattila

The acquisition of late-time imaging is an important step in the analysis of pre-explosion observations of the progenitors of supernovae. We present late-time HST ACS WFC observations of the sites of five Type IIP SNe: 1999ev, 2003gd, 2004A, 2005cs and 2006my. Observations were conducted using the F435W, F555W and F814W filters. We confirm the progenitor ide

Kalpataru Pradhan, Arno P. Kampf

We investigate the electronic reconstruction at the interface between ferromagnetic metallic (FM) and antiferromagnetic insulating (AFI) manganites in superlattices using a two-orbital double-exchange model including superexchange interactions, Jahn-Teller lattice distortions, and long range Coulomb interactions. The magnetic and the transport properties cri

Vincenzo Vitagliano, Valerio Faraoni, Thomas P. Sotiriou, Stefano Liberati

We analyze the apparent horizon dynamics in the inhomogeneous Clifton-Mota-Barrow solution of Brans-Dicke theory. This solution models a central matter configuration embedded in a cosmological background. In certain regions of the parameter space we find solutions exhibiting dynamical creation or merging of two horizons.

M. Kajisawa, Y. Shioya, Y. Aida, Y. Ideue

We investigated the fraction of [OII] emitters in galaxies at z~0.9 as a function of the local galaxy density in the Hubble Space Telescope (HST) COSMOS 2 square degree field. [OII] emitters are selected by the narrow-band excess technique with the NB711-band imaging data taken with Suprime-Cam on the Subaru telescope. We carefully selected 614 photo-z selec

Rao Farhat Masood

In this paper, introduced below are the concepts of digital modulation used in many communication systems today. Techniques described include quadrature phase shift keying (QPSK) and quadrature amplitude modulation (QAM) and how these techniques can be used to increase the capacity and speed of a wireless network. These modulation techniques are the basis of

Raphael Boll, Matteo Petrera, Yuri B. Suris

General Lagrangian theory of discrete one-dimensional integrable systems is illustrated by a detailed study of Bäcklund transformations for Toda-type systems. Commutativity of Bäcklund transformations is shown to be equivalent to consistency of the system of discrete multi-time Euler-Lagrange equations. The precise meaning of the commutativity in the periodi

Vito Foderà, Alessio Zaccone, Marco Lattuada, Athene M. Donald

The possibility for proteins to aggregate in different superstructures, i.e. large-scale polymorphism, has been widely observed, but an understanding of the physico-chemical mechanisms behind it is still out of reach. Here we present a theoretical model for the description of a generic aggregate formed from an ensemble of charged proteins. The model predicts

Henning Bruhn, Oliver Schaudt

Frankl&#39;s union-closed sets conjecture states that in every finite union-closed set of sets, there is an element that is contained in at least half of the member-sets (provided there are at least two members). The conjecture has an equivalent formulation in terms of graphs: In every bipartite graph with least one edge, both colour classes contain a vertex

P. A. Davidson

We propose new scaling laws for the properties of planetary dynamos. In particular, the Rossby number, the magnetic Reynolds number, the ratio of magnetic to kinetic energy, the Ohmic dissipation timescale and the characteristic aspect ratio of the columnar convection cells are all predicted to be power-law functions of two observable quantities: the magneti

Yitping Kok, Vicente Maestro, Michael J Ireland, Peter G Tuthill

The Sydney University Stellar Interferometer (SUSI) has two beam combiners, i.e. the Precision Astronomical Visible Observations (PAVO) and the Microarcsecond University of Sydney Companion Astrometry (MUSCA). The primary beam combiner, PAVO, can be operated independently and is typically used to measure properties of binary stars of less than 50 milliarc- s

Malte Henkel, Shahin Rouhani

Recent developments on emergence of logarithmic terms in correlators or response functions of models which exhibit dynamical symmetries analogous to conformal invariance in not necessarily relativistic systems are reviewed. The main examples of these are logarithmic Schrödinger-invariance and logarithmic conformal Galilean invariance. Some applications of th

Johannes Thürigen

In fundamentally discrete approaches to quantum gravity such as loop quantum gravity, spin-foam models, group field theories or Regge calculus observables are functions on discrete geometries. We present a bra-ket formalism of function spaces and discrete calculus on abstract simplicial complexes equipped with geometry and apply it to the mentioned theories

P. Belli, R. Bernabei, F. Cappella, R. Cerulli

An experiment to search for double beta decay processes in 96Ru and 104Ru, which are accompanied by gamma rays, has been realized in the underground Gran Sasso National Laboratories of the I.N.F.N. (Italy). Ruthenium samples with masses of about (0.5-0.7) kg were measured with the help of ultra-low background high purity Ge gamma ray spectrometry. After 2162

Suryadi Siregar, Endang Soegiartini

Asteroid 1934 CT;1989 AC, well known as 4179 Toutatis, is an Apollo and Mars-crosser asteroid with a chaotic orbit produced by a 3:1 resonance with Jupiter and a 1:4 resonance with the Earth, and frequent close approaches to the Earth. It is listed as a potential hazardous object (PHA). The aim of this study is to investigate the possibility of 4179 Toutatis

Rosy Madaan, A. K. Sharma, Ashutosh Dixit

The research that has been carried out on blogs focused on blog posts only, ignoring the title of the blog page. Also, in summarization only a set of representative sentences are extracted. Some analysis has been done and it has been found that the blog post contains the content that is likely to be related to the topic of the blog post. Thus, proposed syste

Luka Popov

The recent paper published in European Journal of Physics [1] aimed to demonstrate the kinematical and dynamical equivalence of heliocentric and geocentric systems. The work is performed in the Neo-Tychonian system, with key assumption that orbits of distant masses around the Earth are synchronized with the Sun&#39;s orbit. Motion of Sun and Mars have been a

Luciano Campi, Umut Çetin, Albina Danilova

Given a deterministically time-changed Brownian motion $Z$ starting from 1, whose time-change $V(t)$ satisfies $V(t) > t$ for all $t > 0$, we perform an explicit construction of a process $X$ which is Brownian motion in its own filtration and that hits zero for the first time at $V(τ)$, where $τ:= \inf\{t>0: Z_t =0\}$. We also provide the semimartingale deco

Orfeu Bertolami, Ricardo Zambujal Ferreira

In this work we show the existence of traversable wormhole and time-machine solutions in a modified theory of gravity where matter and curvature are nonminimally coupled. Those solutions present a nontrivial redshift function and exist even in the presence of ordinary matter which satisfies the dominant energy condition.

B. Najjari, A. B. Voitkiv

We consider excitation of highly charged hydrogen-like ions by the impact of equivelocity electrons and protons. The kinetic energy of the protons is more than three orders of magnitude larger than that of the equivelocity electrons. It is shown, however, that despite this fact, the electrons can be much more effective in inducing excitation at collision vel

Sascha P. Quanz, Adam Amara, Michael R. Meyer, Matthew A. Kenworthy

We present high-contrast observations of the circumstellar environment of the Herbig Ae/Be star HD100546. The final 3.8 micron image reveals an emission source at a projected separation of 0.48&#34;+-0.04&#34; (corresponding to ~47+-4 AU at a position angle of 8.9+-0.9 degree. The emission appears slightly extended with a point source component with an appar

Lars Grasedyck, Daniel Kressner, Christine Tobler

During the last years, low-rank tensor approximation has been established as a new tool in scientific computing to address large-scale linear and multilinear algebra problems, which would be intractable by classical techniques. This survey attempts to give a literature overview of current developments in this area, with an emphasis on function-related tensor

Xiaojun Bao, Hongfei Zhang, G. Royer, Junqing Li

We systematically calculate the spontaneous fission half-lives for heavy and superheavy nuclei between U and Fl isotopes. The spontaneous fission process is studied within the semi-empirical WKB approximation. The potential barrier is obtained using a generalized liquid drop model, taking into account the nuclear proximity, the mass asymmetry, the phenomenol

Grigori Olshanski

The unitary group U(N) acts by conjugations on the space H(N) of NxN Hermitian matrices, and every orbit of this action carries a unique invariant probability measure called an orbital measure. Consider the projection of the space H(N) onto the real line assigning to an Hermitian matrix its (1,1)-entry. Under this projection, the density of the pushforward o

U. Bak-Steslicka, S. Kolomanski, T. Mrozek

It is well known that there is temporal relationship between coronal mass ejections (CMEs) and associated flares. The duration of the acceleration phase is related to the duration of the rise phase of a flare. We investigate CMEs associated with slow long duration events (LDEs), i.e. flares with the long rising phase. We determined the relationships between

V. D&#39;Elia, M. Perri, S. Puccetti, M. Capalbi

Swift is a multi-wavelength observatory specifically designed for gamma-ray burst (GRB) astronomy that is operational since 2004. Swift is also a very flexible multi-purpose facility that supports a wide range of scientific fields such as active galactic nuclei, supernovae, cataclysmic variables, Galactic transients, active stars and comets. The Swift X-ray

The EDELWEISS collaboration, B. Schmidt, E. Armengaud, C. Augier

A dedicated analysis of the muon-induced background in the EDELWEISS dark matter search has been performed on a data set acquired in 2009 and 2010. The total muon flux underground in the Laboratoire Souterrain de Modane (LSM) was measured to be $Φ_μ=(5.4\pm 0.2 ^{+0.5}_{-0.9})$\,muons/m$^2$/d. The modular design of the muon-veto system allows the reconstruct

Ruggero Pagnan

We present a reading of the traditional syllogistics in a fragment of the propositional intuitionistic multiplicative linear logic and prove that with respect to a diagrammatic logical calculus that we introduced in a previous paper, a syllogism is provable in such a fragment if and only if it is diagrammatically provable. We extend this result to syllogisti

Daichi Asahi, Naoto Nagaosa

We study theoretically the resistance at the interface between the two planar systems with different lattice constants a and b. The resistance and the effect of the magnetic field depends sensitively on the ratio a/b. The size of the enlarged unit cell $λ= n_Aa = n_Bb$ ($n_A$, $n_B$: integers) is the crucial quantity, and the magnetic flux penetrating this e

Cecilia Holmqvist, Mikael Fogelström, Wolfgang Belzig

We investigate the charge and spin transport of a voltage-biased superconducting point contact coupled to a nanomagnet. The magnetization of the nanomagnet is assumed to precess with the Larmor frequency, $ω_L$, due to ferromagnetic resonance. The interplay between the ac Josephson current and the magnetization dynamics leads to spin-polarized Shapiro steps

Eric Tatulli

This paper studies the effects on Zernike coefficients of aperture scaling, translation and rotation, when a given aberrated wavefront is described on the Zernike polynomial basis. It proposes a new analytical method for computing the matrix that enables the building of the transformed Zernike coefficients from the original ones. The technique is based on th

Anna Skripka

This survey on approximations of perturbed operator functions addresses recent advances and some of the successful methods.

Zuo-Bing Wu, Wen-Rui Hu

The overall {\it steady}-state energy balance with two phases in a flow domain requires that the change in energy of the domain is equal to the difference between the total energy entering the domain and that leaving the domain. From the condition, the integral thermal flux across the surface is studied for a {\it steady} thermocapillary drop migration in a

Zuo-Bing Wu

The periodic transference of nucleotide strings in bacterial and archaeal complete genomes is investigated by using the metric representation and the recurrence plot method. The generated periodic correlation structures exhibit four kinds of fundamental transferring characteristics: a single increasing period, several increasing periods, an increasing quasi-

Ery Arias-Castro, Nicolas Verzelen

We formalize the problem of detecting a community in a network into testing whether in a given (random) graph there is a subgraph that is unusually dense. We observe an undirected and unweighted graph on N nodes. Under the null hypothesis, the graph is a realization of an Erdös-Rényi graph with probability p0. Under the (composite) alternative, there is a su

David Gérard-Varet, Matthieu Hillairet, Chao Wang

We consider the free fall of a sphere above a wall in a viscous incompressible fluid. We investigate the influence of boundary conditions on the finite-time occurrence of contact between the sphere and the wall. We prove that slip boundary conditions enable to circumvent the &#34;no-collision&#34; paradox associated with no-slip boundary conditions. We also

Wesam Elshamy

Artificial Intelligence (AI) techniques are known for its ability in tackling problems found to be unyielding to traditional mathematical methods. A recent addition to these techniques are the Computational Intelligence (CI) techniques which, in most cases, are nature or biologically inspired techniques. Different CI techniques found their way to many contro

Yang Han

It is shown that Hattori-Stallings trace induces a homomorphism of abelian groups, called Hattori-Stallings character, from the $K_1$-group of endomorphisms of the perfect derived category of an algebra to its zero-th Hochschild homology, which provides a new proof of Igusa-Liu-Paquette Theorem, i.e., the strong no loop conjecture for finite-dimensional elem

J. S. Aslanides, C. M. Savage

We report on a concept inventory for special relativity: the development process, data analysis methods, and results from an introductory relativity class. The Relativity Concept Inventory tests understanding of kinematic relativistic concepts. An unusual feature is confidence testing for each question. This can provide additional information; for example hi

Al Cheremensky

The paper gives a screw axiomatics of rational mechanics, namely: 1. introduces the main measures of mechanics: the mass measure, the scalar and (vector) screw measures of motion, the (vector) screw measure of impressed action, the increment velocity of the vector measure of motion, the (vector) screw measure of constraint action; 2. postulates the (stronger

Wesam Elshamy

Swarm robotic systems are mainly inspired by swarms of socials insects and the collective emergent behavior that arises from their cooperation at the lower lever. Despite the limited sensory ability, computational power, and communication means of each swarm member, the swarm as a group manages to achieve difficult tasks such as searching for food in terrain

V. Yu. Kachorovskii, S. L. Rumyantsev, W. Knap, M. Shur

We present estimates of the performance limits of terahertz detectors based on the field effect transistors (FET) in the regime of broadband detection. The maximal responsivity is predicted for short-channel FETs in the subthreshold regime. We also calculate the conversion efficiency Q of the device defined as the ratio of the power dissipated by radiation-i

Wesam Elshamy

Topic models are probabilistic models for discovering topical themes in collections of documents. In real world applications, these models provide us with the means of organizing what would otherwise be unstructured collections. They can help us cluster a huge collection into different topics or find a subset of the collection that resembles the topical them

Huatang Tan, F. Bariani, Gaoxiang Li, P. Meystre

We propose a scheme to prepare macroscopic quantum superpositions of motion in optomachanical nano- or micromechanical oscillators quadratically coupled to an intracavity field. The nonlinear optomechanical coupling leads to an effective degenerate three-wave mixing interaction between the mechanical and cavity modes. The quantum superpositions result from t

C. Deng, X. Yao

In this paper, authors show the ill-posedness of 3D incompressible Navier-Stokes equations in the critical Triebel-Lizorkin spaces $ \dot{F}^{-1,q}_{\infty} (\mathbb{R}^3) $ for any $ q>2 $ in the sense that arbitrarily small initial data of $ \dot{F}^{-1,q}_{\infty}(\mathbb{R}^3) $ can lead the corresponding solution to become arbitrarily large after an arb

A. Meena, K. Raja

The Positron Emission Tomography (PET) scan image requires expertise in the segmentation where clustering algorithm plays an important role in the automation process. The algorithm optimization is concluded based on the performance, quality and number of clusters extracted. This paper is proposed to study the commonly used K Means clustering algorithm and to

R. Santhi, B. Priya, J. M. Nandhini

With advancement in computer science research on artificial intelligence and in cognitive psychology research on human learning and performance, the next generation of computer-based tutoring systems moved beyond the simple presentation of pages of text or graphics. These new intelligent tutoring systems (ITSs) called cognitive tutors; incorporated model-tra

Hassan M Emara, Wesam Elshamy, Ahmed Bahgat

This paper presents a new technique for induction motor parameter identification. The proposed technique is based on a simple startup test using a standard V/F inverter. The recorded startup currents are compared to that obtained by simulation of an induction motor model. A Modified PSO optimization is used to find out the best model parameter that minimizes