May 2010 arXiv papers — page 44

Chris C. T. Pringle, Rich R. Kerswell

Two approaches to the problem of transition to turbulence of shear flows are popular in the literature. The first is the linear one of transient growth which focuses on the likely form of the most 'dangerous' (lowest energy) turbulence-triggering disturbances. The second is the nonlinear calculation of the laminar-turbulent boundary which instead foc

P. Fonte, P. Martinengo, E. Nappi, R. Oliveira

We describe the most recent efforts made by various groups in implementing resistive electrodes in micropattern gaseous detectors with the aim to combine in the same design the best features of RPCs (for the example, their robustness and spark protection property) with the high granularity and thus the good position resolution offered by microelectronic tech

E. Čižmár, M. Ozerov, J. Wosnitza, B. Thielemann

Magnetic excitations in the spin-ladder material (C$_5$H$_{12}$N)$_2$CuBr$_4$ [BPCB] are probed by high-resolution multi-frequency electron spin resonance (ESR) spectroscopy. Our experiments provide a direct evidence for a biaxial anisotropy ($\sim 5\%$ of the dominant exchange interaction), that is in contrast to a fully isotropic spin-ladder model employed

C. Gruppioni, F. Pozzi, P. Andreani, G. Rodighiero

We exploit the deepest existing far-infrared (FIR) data obtained so far by Herschel at 100 and 160 um in the GOODS-N, as part of the PACS Evolutionary Probe (PEP) survey, to derive for the first time the evolution of the rest-frame 60-um, 90-um, and total IR luminosity functions (LFs) of galaxies and AGNs from z=0 to unprecedented high redshifts (z~2-3). The

Karin Schnass, Pierre Vandergheynst

This article presents a new classification framework that can extract individual features per class. The scheme is based on a model of incoherent subspaces, each one associated to one class, and a model on how the elements in a class are represented in this subspace. After the theoretical analysis an alternate projection algorithm to find such a collection i

Vladlen G. Shvedov, Cyril Hnatovsky, Wieslaw Krolikowski, Andrei V. Rode

We describe an optical beam converter for an efficient transformation of Gaussian femtosecond laser beams to single- or double-charge vortex beams showing no spatial or topological charge dispersion. The device achieves a conversion efficiency of 75% for single- and 50% for double-charge vortex beams and can operate with high energy broad bandwidth pulses. W

Harry Alles, Jaan Aarik, Aleks Aidla, Aurelien Fay

Atomic layer deposition of ultrathin HfO2 on unmodified graphene from HfCl4 and H2O was investigated. Surface RMS roughness down to 0.5 nm was obtained for amorphous, 30 nm thick hafnia film grown at 180 degrees C. HfO2 was deposited also in a two-step temperature process where the initial growth of about 1 nm at 170 degrees C was continued up to 10-30 nm at

Julien Cohen, Jean-Louis Giavitto, Olivier Michel

In this paper, we build an interpreter by reusing host language functions instead of recoding mechanisms of function application that are already available in the host language (the language which is used to build the interpreter). In order to transform user-defined functions into host language functions we use combinatory logic : lambda-abstractions are tra

Steffen Waldherr, Jingbo Wu, Frank Allgöwer

Cellular transformations which involve a significant phenotypical change of the cell's state use bistable biochemical switches as underlying decision systems. In this work, we aim at linking cellular decisions taking place on a time scale of years to decades with the biochemical dynamics in signal transduction and gene regulation, occuring on a time scal

Jiri Chaloupka, Giniyat Khaliullin

A hypothetical layered oxide La_2NiMO_6 where NiO_2 and MO_2 planes alternate along the c-axis of ABO_3 perovskite lattice is considered theoretically. Here, M denotes a trivalent cation Al, Ga,... such that MO_2 planes are insulating and suppress the c-axis charge transfer. We predict that correlated e_g electrons in the NiO_2 planes develop a planar x^2-y^

William W. L. Chen, Giancarlo Travaglini

For every unit vector $σ\inΣ_{d-1}$ and every $r\ge0$, let % % \begin{displaymath} P_{σ,r}=[-1,1]^d\cap\{t\in\Rr^d:t\cdotσ\le r\} \end{displaymath} % % denote the intersection of the cube $[-1,1]^d$ with a half-space containing the origin $0\in\Rr^d$. We prove that if $N$ is the $d$-th power of an odd integer, then there exists a distribution $\PPP$ of $N$ p

G. Viau, V. Colliere, G. A. Shafeev

Al NPs are synthesized by laser ablation of a bulk Al target immersed into liquid ethanol saturated with hydrogen at atmospheric pressure. The nanoparticles possess a well-distinguished core-shell structure. High Resolution Transmission Electron Microscopy shows several layers inside the Al nanoparticle: oxide layer, amorphous Al, single crystal Al, and a ca

M. Houzet, P. Samuelsson

We investigate theoretically charge transport in hybrid multiterminal junctions with superconducting leads kept at different voltages. It is found that multiple Andreev reflections involving several superconducting leads give rise to rich subharmonic gap structures in the current-voltage characteristics. The structures are evidenced numerically in junctions

Ira Didenkulova, Efim Pelinovsky

The problem of tsunami wave shoaling and runup in U-shaped bays (such as fjords) and underwater canyons is studied in the framework of shallow water theory. The wave shoaling in bays, when the depth varies smoothly along the channel axis, is studied with the use of asymptotic approach. In this case a weak reflection provides significant shoaling effects. The

S. K. Patra, R. K. Choudhury, L. Satpathy

The anatomy of neck configuration in the fission decay of Uranium and Thorium isotopes is investigated in a microscopic study using Relativistic mean field theory. The study includes $^{236}U$ and $^{232}Th$ in the valley of stability and exotic neutron rich isotopes $^{250}U$, $^{256}U$, $^{260}U$, $^{240}Th$, $^{250}Th$, $^{256}Th$ likely to play important

M. Massardi, R. D. Ekers, S. C. Ellis, B. Maughan

X-ray observations of galaxy clusters at high redshift (z>0.5) indicate that they are more morphologically complex and less virialized than those at low-redshift. We present the first subarcmin resolution at 18 GHz observations of the Sunyaev-Zel'dovich (SZ) effect for ClJ0152-1357 using the Australia Telescope Compact Array. ClJ0152-1357 is a massive cl

Huajun Qin, Junren Shi, Yanwei Cao, Kehui Wu

High-resolution electron energy loss spectroscopy measurements have been carried out on an optimally doped cuprate Bi2Sr2CaCu2O8+δ. The momentum-dependent linewidth and the dispersion of an A1 optical phonon are obtained. Based on these data as well as the detailed knowledge of the electronic structure from angle-resolved photoemission spectroscopy, we devel

H. J. Hyun, H. K. Park, H. O. Kim, H. Park et al.

We search for dimuon decays of a low mass particle in the decays B0->K*0 X and B0->rho X using a data sample of 657x10^6 B Bbar events collected with the Belle detector at the KEKB asymmetric-energy e^+ e^- collider. We find no evidence for such a particle in the mass range from 212 MeV/c2 to 300 MeV/c2, and set upper limits on its branching fractions. In pa

Mutsuo Oka

Let $f(\bfz,\bar\bfz)$ be a mixed strongly polar homogeneous polynomial of $3$ variables $\bfz=(z_1,z_2, z_3)$. It defines a Riemann surface $V:=\{[\bfz]\in \BP^{2}\,|\,f(\bfz,\bar\bfz)=0 \}$ in the complex projective space $\BP^{2}$. We will show that for an arbitrary given $g\ge 0$, there exists a mixed polar homogeneous polynomial with polar degree 1 whic

T. Ito, K. Nomura, N. Shibata

We study the fractional quantum Hall effect at filling fractions 7/3 and 5/2 in the presence of the spin-orbit interaction, using the exact diagonalization method and the density matrix renormalization group (DMRG) method in a spherical geometry. Trial wave functions at these fillings are the Laughlin state and the Moore-Reed-Pfaffian state. The ground state

Nathan Clisby

The pivot algorithm for self-avoiding walks has been implemented in a manner which is dramatically faster than previous implementations, enabling extremely long walks to be efficiently simulated. We explicitly describe the data structures and algorithms used, and provide a heuristic argument that the mean time per attempted pivot for $N$-step self-avoiding w

C. Balpardo, M. E. Capoulat, D. Rodrigues, P. Arenillas

The nuclide 241Am decays by alpha emission to 237Np. Most of the decays (84.6 %) populate the excited level of 237Np with energy of 59.54 keV. Digital Coincidence Counting was applied to standardize a solution of 241Am by alpha-gamma coincidence counting with efficiency extrapolation. Electronic discrimination was implemented with a pressurized proportional

Vladimir Kopeliovich, Irina Potashnikova

We demonstrate that so called "infrared divergences" which have been discussed in some publications during several years, do not appear within the correct treatment of analytical properties of the transition amplitudes, in particular, of the second order pole structure of the amplitudes describing the $n - \bar n$ transition in nuclei. Explicit calcu

Javier Rojo, Tuan Nguyen

The Johnson-Lindenstrauss Lemma allows for the projection of $n$ points in $p-$dimensional Euclidean space onto a $k-$dimensional Euclidean space, with $k \ge \frac{24\ln \emph{n}}{3ε^2-2ε^3}$, so that the pairwise distances are preserved within a factor of $1\pmε$. Here, working directly with the distributions of the random distances rather than resorting t

Guo-Li Liu

We consider the contributions of the extra gauge boson Z' to the like sign $τ$ production process $e^-γ\to e^+(μ^+)τ^-τ^-$, induced by the tree-level flavor changing interactions. Since these rare production are far below the observable level in the Standard Model and other popular new physics models such as the minimal supersymmetric model, we find that

I. M. Sokolov, D. V. Kupriyanov, R. G. Olave, M. D. Havey

High-density and ultracold atomic gases have emerged as promising media for storage of individual photons for quantum memory applications. In this paper we provide an overview of our theoretical and experimental efforts in this direction, with particular attention paid to manipulation of light storage (a) through complex recurrent optical scattering processe

N. Sh. Izmailian, Ming-Chang Huang

We analyze the exact formulae for the resistance between two arbitrary notes in a rectangular network of resistors under free, periodic and cylindrical boundary conditions obtained by Wu [J. Phys. A 37, 6653 (2004)]. Based on such expression, we then apply the algorithm of Ivashkevich, Izmailian and Hu [J. Phys. A 35, 5543 (2002)] to derive the exact asympto

Paul O'Hara

In a previous article a relationship was established between the linearized metrics of General Relativity associated with geodesics and the Dirac Equation of quantum mechanics. In this paper the extension of that result to arbitrary curves is investigated. In the case of scalar fields, a relationship between mass and temperature is also worked out.

Jinpeng An

By using a Borel density theorem for algebraic quotients, we prove a theorem concerning isometric actions of a Lie group $G$ on a smooth or analytic manifold $M$ with a rigid $\mathrm{A}$-structure $σ$. It generalizes Gromov's centralizer and representation theorems to the case where $R(G)$ is split solvable and $G/R(G)$ has no compact factors, strengthe

C. Chicone, B. Mashhoon

We present a family of dynamic rotating cylindrically symmetric Ricci-flat gravitational fields whose geodesic motions have the structure of gravitomagnetic jets. These correspond to helical motions of free test particles up and down parallel to the axis of cylindrical symmetry and are reminiscent of the motion of test charges in a magnetic field. The speed

Amir Shachar

The Integral Image algorithm is often applied in tasks that require efficient integration over images, such as object detection. In this paper we discuss theoretical aspects of the algorithm's continuous version. We suggest to define the coefficients at the formulation of the algorithm by applying a novel kind of discrete derivative. Based on that operat

Manuel De la Rosa, Leonhard Frerick, Sophie Grivaux, Alfredo Peris

We prove that if X is any complex separable infinite-dimensional Banach space with an unconditional Schauder decomposition, X supports an operator T which is chaotic and frequently hypercyclic. In contrast with the complex case, we observe that there are real Banach spaces with an unconditional basis which support no chaotic operator.

Marianne Rotter, Christine Hieke, Dirk Johrendt

Superconductivity up to 30 K in charge neutrally doped BaFe2[As(1-x)P(x)]2 has been ascribed to chemical pressure, caused by the shrinking unit cell. But the latter induces no superconductivity in [Ba(1-x)Sr(x)]Fe2As2 in spite of the same volume range. We show that the spin-density-wave (SDW) state of BaFe2As2 becomes suppressed in BaFe2[As(1-x)P(x)]2 by a s

Giovanni Cerulli Irelli, Gregoire Dupont, Francesco Esposito

In recent articles, the investigation of atomic bases in cluster algebras associated to affine quivers led the second-named author to introduce a variety called transverse quiver Grassmannian and the first-named and third-named authors to consider the smooth loci of quiver Grassmannians. In this paper, we prove that, for any affine quiver Q, the transverse q

Deyou Chen, Peng Wang, Houwen Wu, Haitang Yang

Motivated by the recent work of the hidden conformal symmetry of the Kerr black hole, we investigate the hidden conformal symmetry of a Kerr-Sen black hole and a Kerr-Newman-Kasuya black hole. Our result shows the conformal symmetry is spontaneously broken due to the periodicity of the azimuthal angle. The absorption across section is in consistence with the

Mihai Turinici

A refinement of Zhong's variational principle [Nonlin. Anal., 29 (1997), 1421-1431] is given, in the realm of almost metric structures. Applications to equilibrium points are also provided.

Yue Yu, Kun Yang

We study a cold atom-molecule mixture in two-dimensional optical lattices, in which fermionic atoms have a Dirac-type dispersion. We show that by fine-tuning the atomic and molecular interactions, such mixtures can simulate Wess-Zumino supersymmetry (SUSY) model, the first example of SUSY theories. At zero temperature, SUSY is not spontaneously broken for th

Ron Rosenthal

We consider a model for random walks on random environments (RWRE) with random subset of the d-dimensional Euclidean lattice as the vertices, and uniform transition probabilities on 2d points (two "coordinate nearest points" in each of the d coordinate directions). We prove that the velocity of such random walks is almost surely 0, and give partial c

Laurent Hébert-Dufresne, Pierre-André Noël, Vincent Marceau, Antoine Allard

Analytical description of propagation phenomena on random networks has flourished in recent years, yet more complex systems have mainly been studied through numerical means. In this paper, a mean-field description is used to coherently couple the dynamics of the network elements (nodes, vertices, individuals...) on the one hand and their recurrent topologica

Michael Skeide

We present a far reaching generalization of a factorization theorem by Bhat, Ramesh, and Sumesh (stated first by Asadi) and furnish a very quick proof.

L. Ermann, A. D. Chepelianskii, D. L. Shepelyansky

We study the properties of spectrum and eigenstates of the Google matrix of a directed network formed by the procedure calls in the Linux Kernel. Our results obtained for various versions of the Linux Kernel show that the spectrum is characterized by the fractal Weyl law established recently for systems of quantum chaotic scattering and the Perron-Frobenius

Siddharth Savyasachi Malu, Sanjay K. Pandey

This study unveils new insights into the Bullet Cluster through cm-wave observations made with the Australia Telescope Compact Array, focusing on the Sunyaev-Zeldovich Effect (SZE). A novel SZE feature was discovered, distinctively offset from the X-ray brightness peak, challenging conventional associations between such phenomena. The findings, achieved thro

Shun Maeta

J.Eells and L. Lemaire introduced k-harmonic maps, and T. Ichiyama, J. Inoguchi and H.Urakawa showed the first variation formula. In this paper, we describe the ordinary differential equations of $3$-harmonic curves into a Riemannian manifold with constant sectional curvature, and show biharmonic curve is k-harmonic curve $(k\geq 2)$.

Ryu Makiya, Tomonori Totani, Masakazu A. R. Kobayashi

We present a new theoretical calculation of the contribution to the extragalactic gamma-ray background radiation (EGRB) from star-forming galaxies, based on a state-of-the-art model of hierarchical galaxy formation that is in quantitative agreement with a variety of observations of local and high-redshift galaxies. Gamma-ray luminosity ($L_γ$) and spectrum o

Inder Jeet Taneja

In this short note we have produced different kind of magic squares using digital letter having only the algorisms: 0, 1, 2, 5, and 8. The interesting fact in considering these five digits is that the day 8th May 2010 also have these ones (08.05.2010). Moreover, the magic squares presented have some interesting properties, such as: they remains the same if w

G. Fejos, A. Patkos

Dyson-Schwinger equations for the U(n) x U(n) symmetric matrix sigma model reformulated with two auxiliary fields in a background breaking the symmetry to U(n) are studied in the so-called bare vertex approximation. A large n solution is constructed under the supplementary assumption so that the scalar components are much heavier than the pseudoscalars. The

Jie Sun, Erik M. Bollt, Mason A. Porter, Marian S. Dawkins

We formulate a mathematical model for daily activities of a cow (eating, lying down, and standing) in terms of a piecewise affine dynamical system. We analyze the properties of this bovine dynamical system representing the single animal and develop an exact integrative form as a discrete-time mapping. We then couple multiple cow "oscillators" togethe

Joydeep Chakrabortty

We extend the Type I seesaw and suggest a $new$ seesaw mechanism to generate neutrino masses within the left-right symmetric theories where parity is spontaneously broken. We construct a next to minimal left-right symmetric model where neutrino masses are determined irrespective of the B-L breaking scale and call it the $new$ seesaw mechanism. In this scenar

Yaar Solomon

In this paper we show that the function defined by a primitive, star shaped substitu- tion tiling of the plane, can be realized as a Jacobian of a biLipschitz homeomorphism of R^2. In particular it holds for any Penrose tiling.

Johannes Ferber, Yu-Zhong Zhang, Harald O. Jeschke, Roser Valenti

The optical conductivity of LaFeAsO, BaFe$_2$As$_2$, SrFe$_2$As$_2$, and EuFe$_2$As$_2$ in the spin-density wave (SDW) state is investigated within density functional theory (DFT) in the framework of spin-polarized generalized gradient approximation (GGA) and GGA+U. We find a strong dependence of the optical features on the Fe magnetic moments. In order to r

Seok-Jin Kang, Euiyong Park

Using combinatorics of Young tableaux, we give an explicit construction of irreducible graded modules over Khovanov-Lauda-Rouquier algebras $R$ and their cyclotomic quotients $R^λ$ of type $A_{n}$. Our construction is compatible with crystal structure. Let ${\mathbf B}(\infty)$ and ${\mathbf B}(λ)$ be the $U_q(\slm_{n+1})$-crystal consisting of marginally la

Naoyuki Haba, Masaki Hirotsu

We suggest new simple model of generating tiny neutrino masses through a TeV-scale seesaw mechanism without requiring tiny Yukawa couplings. This model is a simple extension of the standard model by introducing extra one Higgs singlet, and one Higgs doublet with a tiny vacuum expectation value. Experimental constraints, electroweak precision data and no larg

Jonathan Ohayon

The aim of this article is to give a quantization of some coisotropic subalgebras in complex semisimple Lie bialgebras. The coisotropic subalgebras that will be quantized are those given by Zambon in his paper "`A Construction for coisotropic subalgebras of Lie Bialgebras"' [Zam08]. We will also extend the construction for the exceptional complex

Itai Benjamini, Van Cyr, Eviatar B. Procaccia, Ran J. Tessler

Which graphs admit an integer value harmonic function which is injective and surjective onto $\Z$? Such a function, which we call harmonic labeling, is constructed when the graph is the $\Z^2$ square grid. It is shown that for any finite graph $G$ containing at least one edge, there is no harmonic labeling of $ G \times \Z$.

Amit Weinstein

A sender wishes to broadcast a message of length $n$ over an alphabet to $r$ users, where each user $i$, $1 \leq i \leq r$ should be able to receive one of $m_i$ possible messages. The broadcast channel has noise for each of the users (possibly different noise for different users), who cannot distinguish between some pairs of letters. The vector $(m_1, m_2,.

K. Bitaghsir Fadafan, B. Pourhassan, J. Sadeghi

In this paper we use the AdS/CFT correspondence to compute the jet-quenching parameter in a N=2 thermal plasma. We consider the general three-charge black hole and discuss some special cases. We add a constant electric field to the background and find the effect of the electric field on the jet-quenching parameter. Also we include higher derivative terms and

Ryusuke Nishikawa, Masashi Kimura

We study gravitational and electromagnetic perturbation around the squashed Kaluza-Klein black holes with charge. Since the black hole spacetime focused on this paper have $SU(2) \times U(1) \simeq U(2)$ symmetry, we can separate the variables of the equations for perturbations by using Wigner function $D^{J}_{KM}$ which is the irreducible representation of

Chun Liu, Shuo Yang

Heavy charged lepton productions via gluon fusion at the LHC are revisited. Full loop calculations are adopted with an updated parton distribution function and electroweak data. Including contribution from new generation quarks in the loop, pair production of the sequential heavy lepton via gluon fusion at the LHC dominates over that via the Drell-Yan mechan

Zongxia Liang, Jicheng Yao

This paper considers nonlinear regular-singular stochastic optimal control of large insurance company. The company controls the reinsurance rate and dividend payout process to maximize the expected present value of the dividend pay-outs until the time of bankruptcy. However, if the optimal dividend barrier is too low to be acceptable, it will make the compan

Zongxia Liang, Jianping Huang

This paper considers optimal control problem of a large insurance company under a fixed insolvency probability. The company controls proportional reinsurance rate, dividend pay-outs and investing process to maximize the expected present value of the dividend pay-outs until the time of bankruptcy. This paper aims at describing the optimal return function as w

Shuqing Jiang, Zongxia Liang, Weiming Wu

This paper works out fair values of stock loan model with automatic termination clause, cap and margin. This stock loan is treated as a generalized perpetual American option with possibly negative interest rate and some constraints. Since it helps a bank to control the risk, the banks charge less service fees compared to stock loans without any constraints.

Zongxia Liang, Jicheng Yao

Based on a point of view that solvency and security are first, this paper considers regular-singular stochastic optimal control problem of a large insurance company facing positive transaction cost asked by reinsurer under solvency constraint. The company controls proportional reinsurance and dividend pay-out policy to maximize the expected present value of

Sin Kyu Kang, Takuya Morozumi, Norimi Yokozaki

We investigate lepton flavor violating (LFV) radiative processes and the relic abundance of neutralino dark matter in supersymmetric type-I seesaw model. We carefully derive threshold corrections to the flavor off-diagonal elements of slepton mass matrix and up-type Higgs mass squared and find that they can be large in the case of large $B_N^0$. We examine h

Eyal Gruss

We consider Horava gravity coupled to Maxwell and higher derivative magnetic terms. We construct static spherically symmetric black hole solutions in the low-energy approximation. We calculate the horizon locations and temperatures in the near-extremal limit, for asymptotically flat and (anti-)de Sitter spaces. We also construct a detailed balanced version o

Michael Viscardi

We extend the definition of an m-stable curve introduced by Smyth to the setting of maps to a projective variety X, generalizing the definition of a Kontsevich stable map in genus one. We prove that the moduli problem of n-pointed m-stable genus one maps of class β is representable by a proper Deligne-Mumford stack \sMbar_{1,n}^m(X, β) over Spec Z[1/6]. For

Ji Young Jo, Rebecca J. Sichel, Ho Nyung Lee, Serge M. Nakhmanson

The origin of the functional properties of complex oxide superlattices can be resolved using time-resolved synchrotron x-ray diffraction into contributions from the component layers making up the repeating unit. The CaTiO3 layers of a CaTiO3/BaTiO3 superlattice have a piezoelectric response to an applied electric field, consistent with a large continuous pol

Hongjie Dong, Seick Kim

We establish Schauder estimates for both divergence and non-divergence form second-order elliptic and parabolic equations involving Hölder semi-norms not with respect to all, but only with respect to some of the independent variables.

Jose Mathew Manimala

The evolution of encryption algorithms have led to the development of very complicated and highly versatile algorithms that sacrifice efficiency for better and harder to decrypt results. But by the application of a genetic schema to the encryption of data, a new structure can be created. Genetic methods and procedures are lethal in the way they handle and ma

Jerzy Matyjasek, Dariusz Tryniecki, Katarzyna Zwierzchowska

The approximation of the renormalized stress-energy tensor of the quantized massive scalar field in Reissner-Nordström spacetime is constructed. It is achieved by functional differentiation of the first two nonvanishing terms of the Schwinger-DeWitt expansion involving the coincidence limit of the Hadamard-Minakshisundaram-DeWitt-Seely coefficients $[a_{3}]$

Xian-Min Jin, Jügen Röch, Juan Yin, Tao Yang

We experimentally demonstrate a non-local generation of entanglement from two independent photonic sources in an ancilla-free process . Two bosons (photons) are entangled in polarization space by steering into a novel interferometer setup, in which they have never meet each other. The entangled photons are delivered to polarization analyzers in different sit

Daniel James Shepherd

A dissertation submitted to the University of Bristol in accordance with the requirements of the degree of Doctor of Philosophy (PhD) in the Faculty of Engineering, Department of Computer Science, July 2009.

Ricardo D. Katz, Hans Schneider, Sergei Sergeev

This paper studies commuting matrices in max algebra and nonnegative linear algebra. Our starting point is the existence of a common eigenvector, which directly leads to max analogues of some classical results for complex matrices. We also investigate Frobenius normal forms of commuting matrices, particularly when the Perron roots of the components are disti

Andrei K. Lerner

We prove sharp $L^p(w)$ norm inequalities for the intrinsic square function (introduced recently by M. Wilson) in terms of the $A_p$ characteristic of $w$ for all $1<p<\infty$. This implies the same sharp inequalities for the classical Lusin area integral $S(f)$, the Littlewood-Paley $g$-function, and their continuous analogs $S_ψ$ and $g_ψ$. Also, as a coro

E. I. Guendelman

A general coordinate invariant theory is constructed where confinement of gauge fields and gauge dynamics in general is governed by the spontaneous symmetry breaking (s.s.b.) of scale invariance. The model uses two measures of integration in the action, the standard $\sqrt{-g}$ where $g$ is the determinant of the metric and another measure $Φ$ independent of

Mark Haskins, Nikolaos Kapouleas

We construct $\sorth{p} \times \sorth{q}$-invariant special Lagrangian (SL) cones in $\C^{p+q}$. These SL cones are natural higher-dimensional analogues of the $\sorth{2}$-invariant SL cones constructed previously by MH and used in our gluing constructions of higher genus SL cones in $\C^{3}$. We study in detail the geometry of these $\sorth{p}\times \sorth{

Youssef Elfoutayeni, Mohamed Khaladi

The linear complementarity problem is to find vector $z$ in $\mathrm{IR}^{n}$ satisfying $z^{T}(Mz+q)=0$, $Mz+q\geqslant0,$ $z\geqslant0$, where $M$ as a matrix and $q$ as a vector, are given data; this problem becomes in present the subject of much important research because it arises in many areas and it includes important fields, we cite for example the l

I. V. Arzhantsev, E. A. Makedonskii, A. P. Petravchuk

Let W_n(K) be the Lie algebra of derivations of the polynomial algebra K[X]:=K[x_1,...,x_n] over an algebraically closed field K of characteristic zero. A subalgebra L of W_n(K) is called polynomial if it is a submodule of the K[X]-module W_n(K). We prove that the centralizer of every nonzero element in L is abelian provided L has rank one. This allows to cl

A. D. Alhaidari

We propose a relativistic one-parameter Hermitian theory for the Coulomb problem with an electric charge greater than 137. In the non-relativistic limit, the theory becomes identical to the Schrödinger-Coulomb problem for all Z. Moreover, it agrees with the Dirac-Coulomb problem to order (\alph Z)^2, where αis the fine structure constant. The vacuum in the t

A. D. Alhaidari

We obtain an analytic solution for a three-parameter class of logarithmic potentials at zero energy. The potential terms are products of the inverse square and the inverse log to powers 2, 1 and 0. The configuration space is the one-dimensional box. Using point canonical transformation, we simplify the solution by mapping the problem into the oscillator prob

P. M. Krstajić, M. Helm, F. Peeters

The magnetic-field dependence of the energy spectrum of GaAs doped with nitrogen impurities is investigated. Our theoretical model is based on the phenomenological Band Anticrossing Model (BAC) which we extended in order to include magnetic field and electron - phonon interaction. Due to the highly localized nature of the nitrogen state, we find that the ene

Jennie D&#39;Ambroise

We show that Einstein&#39;s gravitational field equations for the Friedmann-Robertson-Lemaître-Walker (FRLW) and for two conformal versions of the Bianchi I and Bianchi V perfect fluid scalar field cosmological models, can be equivalently reformulated in terms of a single equation of either generalized Ermakov-Milne-Pinney (EMP) or (non)linear Schrödinger (N

Daniel A. Klain

This article describes a new proof of the equality condition for the Brunn-Minkowski inequality.

Dastgeer Shaikh

{\em Voyager 1} and {\em 2} data reveals that magnetic field fluctuations are compressive and exhibit a Gaussian distribution in the compressed heliosheath plasma, whereas they follow a lognormal distribution in a nearly incompressible supersonic solar wind plasma. To describe the evolution of magnetic field, we develop a nonlinear simulation model of a part

Michael J. Bremner, Richard Jozsa, Dan J. Shepherd

We consider quantum computations comprising only commuting gates, known as IQP computations, and provide compelling evidence that the task of sampling their output probability distributions is unlikely to be achievable by any efficient classical means. More specifically we introduce the class post-IQP of languages decided with bounded error by uniform famili

R. Yadav, M. Chandra, M. K. Verma, S. Paul

We perform spectral simulations of dynamo for magnetic Prandtl number of one with Taylor-Green forcing. We observe dynamo transition through a supercritical pitchfork bifurcation. Beyond the transition, the numerical simulations reveal complex dynamo states with windows of constant, periodic, quasiperiodic, and chaotic magnetic field configurations. For some

Mircea Neagu, Constantin Udriste

In this paper we construct the differential equations of the stream lines that characterize plasma regarded as a non-isotropic medium geometrized by a jet rheonomic time-invariant Berwald-Moor metric. Section 1 contains historical notes regarding the Plasma Physics and its geometrical description. Section 2 analyzes the generalized Lagrange geometrical appro

Daryl Preece, Rebecca Warren, Manlio Tassieri, R. M. L. Evans

Microrheology is a branch of rheology having the same principles as conventional bulk rheology, but working on micron length scales and micro-litre volumes. Optical tweezers have been successfully used with Newtonian fluids for rheological purposes such as determining fluid viscosity. Conversely, when optical tweezers are used to measure the viscoelastic pro

Masaharu Isobe, Berni J. Alder

The molasses tail in dense hard core fluids is investigated by extensive event-driven molecular dynamics simulation through the orientational autocorrelation functions. Near the fluid-solid phase transition, there exist three regimes in the relaxation of the pair orientational autocorrelation function, namely the kinetic, molasses (stretched exponential), an

Jacob Fox, Mikhail Gromov, Vincent Lafforgue, Assaf Naor

The {\em overlap number} of a finite $(d+1)$-uniform hypergraph $H$ is defined as the largest constant $c(H)\in (0,1]$ such that no matter how we map the vertices of $H$ into $\R^d$, there is a point covered by at least a $c(H)$-fraction of the simplices induced by the images of its hyperedges. In~\cite{Gro2}, motivated by the search for an analogue of the n

Juan Dominguez-Montes

This work deals with a classic problem: &#34;Given a set of coins among which there is a counterfeit coin of a different weight, find this counterfeit coin using ordinary balance scales, with the minimum number of weighings possible, and indicate whether it weighs less or more than the rest&#34;. The method proposed here not only calculates the minimum numbe

K. Saifullah, K. Usman

Approximate symmetries of geodesic equations on 2-spheres are studied. These are the symmetries of the perturbed geodesic equations which represent approximate path of a particle rather than exact path. After giving the exact symmetries of the geodesic equations, two different approaches to study the approximate symmetries of the approximate geodesic equatio

M. Akbar, K. Saifullah

Using the exactness criteria of entropy from the first law of black hole thermodynamics, we study quantum corrections for axially symmetric black holes.

A. R. Kashif, K. Saifullah

Lie symmetries of various geometrical and physical quantities in general relativity play an important role in understanding the curvature structure of manifolds. The Riemann curvature and Weyl tensors are two fourth-rank tensors in the theory. Interrelations between the symmetries of these two tensors (known as collineations) are studied. Some illustrative e

Asghar Qadir, K. Saifullah

It is shown that when the stress-energy tensor of a spacetime is diagonal and is written in the mixed form, its collineations admit infinite dimensional Lie algebras except possibly in the case when the tensor depends on all the spacetime coordinates. The result can be extended for more general second rank tensors.

Ugur Camci, Asghar Qadir, K. Saifullah

Conformal Ricci collineations of static spherically symmetric spacetimes are studied. The general form of the vector fields generating conformal Ricci collineations is found when the Ricci tensor is non-degenerate, in which case the number of independent conformal Ricci collineations is \emph{fifteen}; the maximum number for 4-dimensional manifolds. In the d

Asghar Qadir, K. Saifullah

Comments are made on some recently published papers on matter collineations of plane symmetric, cylindrically symmetric and spherically symmetric spacetimes.

Hiroki Yatou

We find three types of steady solutions and remarkable flow pattern transitions between them in a two-dimensional wavy-walled channel for low to moderate Reynolds (Re) and Weissenberg (Wi) numbers using direct numerical simulations with spectral element method. The solutions are called &#34;convective&#34;, &#34;transition&#34;, and &#34;elastic&#34; in asce

R. Koushik, Matthias Baenninger, Vijay Narayan, Subroto Mukerjee

Topological defects are ubiquitous from solid state physics to cosmology, where they drive phase transitions by proliferating as domain walls, monopoles or vortices. As quantum excitations, they often display fractional charge and anyonic statistics, making them relevant to topologically protected quantum computation, but realizing a controlled physical reso

Gevorg Muradyan, Atom Zh. Muradyan

We develop an analytical approach for probability amplitudes of Kapitza-Dirac effect that merge together the Raman-Nath and Bragg regimes of interaction.

M. Goteman, U. Lindstrom

We discuss additional supersymmetries for N = (2, 2) supersymmetric non-linear sigma models described by left and right semichiral superfields.