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Sep 23, 2013
09/13

by
S. Baunack; K. Aulenbacher; D. Balaguer Ríos; L. Capozza; J. Diefenbach; B. Gläser; D. v. Harrach; Y. Imai; E. M. Kabuß; R. Kothe; J. H. Lee; H. Merkel; M. C. Mora Espí; U. Müller; E. Schilling; G. Stephan; C. Weinrich; J. Arvieux; M. A. El-Yakoubi; R. Kunne; F. E. Maas; M. Morlet; S. Ong; J. van de Wiele; S. Kowalski; Y. Prok; S. Taylor

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A new measurement of the parity violating asymmetry in elastic electron scattering on hydrogen at backward angles and at a four momentum transfer of Q^2=0.22 (GeV/c)^2 is reported here. The measured asymmetry is A_LR=(-17.23 +- 0.82_stat +-0.89_syst) ppm. The Standard Model prediction assuming no strangeness is A_0=(-15.87 +- 1.22) ppm. In combination with previous results from measurements at forward angles, it it possible to disentangle for the first time the strange electric and magnetic...

Source: http://arxiv.org/abs/0903.2733v1

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Sep 23, 2013
09/13

by
L. H. Ford; N. F. Svaiter

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Quantum fluctuations in the density of a fluid with a linear phonon dispersion relation are studied. In particular, we treat the changes in these fluctuations due to non-classical states of phonons and to the presence of boundaries. These effects are analogous to similar effects in relativistic quantum field theory, and we argue that the case of the fluid is a useful analog model for effects in field theory. We further argue that the changes in the mean squared density are in principle...

Source: http://arxiv.org/abs/0903.2694v1

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Sep 20, 2013
09/13

by
Peter K. F. Kuhfittig

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The purpose of this paper is to examine the possible existence or construction of traversable wormholes supported by generalized Chaplygin gas (GCG) by starting with a general line element and the Einstein tensor, together with the equation of state, thereby continuing an earlier study by the author of wormholes supported by phantom energy. Numerical techniques are used to demonstrate the existence of wormhole spacetimes that (1) meet the flare-out conditions at the throat, (2) are traversable...

Source: http://arxiv.org/abs/0802.3656v3

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Sep 23, 2013
09/13

by
S. T. Belinschi; D. Shlyakhtenko

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In this paper we give an analytic interpretation of free convolution of type B, introduced by Biane, Goodman and Nica, and provide a new formula for its computation. This formula allows us to show that free additive convolution of type B is essentially a re-casting of conditionally free convolution. We put in evidence several aspects of this operation, the most significant being its apparition as an 'intertwiner' between derivation and free convolution of type A. We also show connections...

Source: http://arxiv.org/abs/0903.2721v1

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Sep 23, 2013
09/13

by
Charles P. Meaney; Tim Duty; Ross H. McKenzie; Gerard J. Milburn

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We consider the steady states of a harmonic oscillator coupled so strongly to a two-level system (a qubit) that the rotating wave approximation cannot be made. The Hamiltonian version of this model is known as the $E\otimes\beta$ Jahn-Teller model. The semiclassical version of this system exhibits a fixed point bifurcation, which in the quantum model leads to a ground state with substantial entanglement between the oscillator and the qubit. We show that the dynamical bifurcation survives in a...

Source: http://arxiv.org/abs/0903.2681v1

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Sep 23, 2013
09/13

by
Jose A. Diaz-Garcia; R. Gutierrez-Jaimez

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Several matrix variate hypergeometric type distributions are derived. The compound distributions of left-spherical matrix variate elliptical distributions and inverted hypergeometric type distributions with matrix arguments are then proposed. The scale mixture of left-spherical matrix variate elliptical distributions and univariate inverted hypergeometric type distributions is also derived as a particular case of the compound distribution approach.

Source: http://arxiv.org/abs/0903.2875v1

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Sep 23, 2013
09/13

by
Frans Snik; Radek Melich; Christoph Keller

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We present the design and the prototype of the Small Synoptic Second Solar Spectrum Telescope (S5T), which can autonomously measure scattering polarization signals on a daily basis with large sensitivity and accuracy. Its data will be used to investigate the nature of weak, turbulent magnetic fields through the Hanle effect in many lines. Also the relation between those fields and the global solar dynamo can be revealed by spanning the observations over a significant fraction of a solar cycle....

Source: http://arxiv.org/abs/0903.2730v1

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Sep 23, 2013
09/13

by
Daniel Allcock

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We prove the following: there are infinitely many finite-covolume (resp. cocompact) Coxeter groups acting on hyperbolic space H^n for every n < 20 (resp. n < 7). When n=7 or 8, they may be taken to be nonarithmetic. Furthermore, for 1 < n < 20, with the possible exceptions n=16 and 17, the number of essentially distinct Coxeter groups in H^n with noncompact fundamental domain of volume less than or equal to V grows at least exponentially with respect to V. The same result holds for...

Source: http://arxiv.org/abs/0903.0138v2

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Sep 23, 2013
09/13

by
Valerie J. Mikles; Peggy Varniere; Stephen S. Eikenberry; Jerome Rodriguez; Dave Rothstein

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It is widely believed that the low frequency quasi-periodic X-ray oscillations observed in microquasars are correlated to, but do not originate at, the physical radius of the inner edge of the accretion disk. Models relating the QPO frequency and color radius are hindered by observations showing contradicting trend correlations between the microquasars GRO 1655-40, XTE J1550-564 and GRS 1915+105. The first shows a negative correlation and the latter two a positive one. By taking into account...

Source: http://arxiv.org/abs/0903.2680v1

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Sep 23, 2013
09/13

by
Susmit Jha; Sanjit A. Seshia; Rhishikesh Limaye

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Satisfiability solvers are increasingly playing a key role in software verification, with particularly effective use in the analysis of security vulnerabilities. String processing is a key part of many software applications, such as browsers and web servers. These applications are susceptible to attacks through malicious data received over network. Automated tools for analyzing the security of such applications, thus need to reason about strings. For efficiency reasons, it is desirable to have...

Source: http://arxiv.org/abs/0903.2825v1

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Sep 22, 2013
09/13

by
Armin Lühr; Alejandro Saenz

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The stopping power of antiprotons in atomic and molecular hydrogen as well as helium was calculated in an impact-energy range from 1 keV to 6.4 MeV. In the case of H2 and He the targets were described with a single-active electron model centered on the target. The collision process was treated with the close-coupling formulation of the impact-parameter method. An extensive comparison of the present results with theoretical and experimental literature data was performed in order to evaluate...

Source: http://arxiv.org/abs/0812.5058v2

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Sep 23, 2013
09/13

by
N. N. Nikolaev; V. R. Zoller

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One of the well known effects of the asymptotic freedom is splitting of the leading-$\log$ BFKL pomeron into a series of isolated poles in complex angular momentum plane. Following our earlier works we explore the phenomenological consequences of the emerging BFKL-Regge factorized expansion for the small-$x$ charm ($F_2^c$) and beauty ($F_{2}^{b}$) structure functions of the proton. As we found earlier,the color dipole approach to the BFKL dynamics predicts uniquely decoupling of subleading...

Source: http://arxiv.org/abs/0903.2729v1

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Sep 23, 2013
09/13

by
Frédéric Faure

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We consider a simple model of partially expanding map on the torus. We study the spectrum of the Ruelle transfer operator and show that in the limit of high frequencies in the neutral direction (this is a semiclassical limit), the spectrum develops a spectral gap, for a generic map. This result has already been obtained by M. Tsujii (05). The novelty here is that we use semiclassical analysis which provides a different and quite natural description. We show that the transfer operator is a...

Source: http://arxiv.org/abs/0903.2747v1

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Sep 23, 2013
09/13

by
Lisa Winter; Richard Mushotzky; Yuichi Terashima; Yoshihiro Ueda

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The fraction of Compton thick sources is one of the main uncertainties left in understanding the AGN population. The Swift Burst Alert Telescope (BAT) all-sky survey, for the first time gives us an unbiased sample of AGN for all but the most heavily absorbed sources (log NH > 25). Still, the BAT spectra (14 - 195 keV) are time-averaged over months of observations and therefore hard to compare with softer spectra from the Swift XRT or other missions. This makes it difficult to distinguish...

Source: http://arxiv.org/abs/0903.2802v1

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Sep 23, 2013
09/13

by
Garry W. Angus; Antonaldo Diaferio

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We re-investigate the old problem of the survival of the five globular clusters orbiting the Fornax dwarf galaxy in both standard and modified Newtonian dynamics. For the first time in the history of the topic, we use accurate mass models for the Fornax dwarf, obtained through Jeans modelling of the recently published line of sight velocity dispersion data, and we are also not resigned to circular orbits for the globular clusters. Previously conceived problems stem from fixing the starting...

Source: http://arxiv.org/abs/0903.2874v1

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Sep 23, 2013
09/13

by
Pierre Andreoletti

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We study a random walk in a random environment (RWRE) on $\Z^d$, $1 \leq d < +\infty$. The main assumptions are that conditionned on the environment the random walk is reversible. Moreover we construct our environment in such a way that the walk can't be trapped on a single point like in some particular RWRE but in some specific d-1 surfaces. These surfaces are basic surfaces with deterministic geometry. We prove that the local time in the neighborhood of these surfaces is driven by a...

Source: http://arxiv.org/abs/0903.2696v1

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Sep 17, 2013
09/13

by
Tobias Salger; Gunnar Ritt; Carsten Geckeler; Sebastian Kling; Martin Weitz

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We report on experiments studying transport properties of an atomic Bose-Einstein condensate in an optical lattice of spatial period $\lambda/2n$, where $n$ is an integer, realized with the dispersion of multiphoton Raman transitions. We observe Bloch oscillations, as a clear effect of quantum transport, in the sub-wavelength scale periodicity lattice. The unusually strong localisation of atoms is evident from the measured effective mass. Future prospects of the novel lattice structures are...

Source: http://arxiv.org/abs/0711.1772v3

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108

Sep 23, 2013
09/13

by
Xavier Caicedo; Ricardo Oscar Rodriguez

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In this paper we consider an approach where both propositions and the accessibility relation are infinitely many-valued over G\"{o}del algebras. In particular, we consider separately the $\Box $-fragment and the $\Diamond $-fragment of our G\"{o}del modal logic and prove that both logics are complete with respect to the class of models with values in the linear Hetying algebra [0,1]. In addition, we show that the first fragment is uniquely determined by the class of models having...

Source: http://arxiv.org/abs/0903.2767v1

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131

Sep 23, 2013
09/13

by
A. Iucci; M. A. Cazalilla

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The dynamics of the Luttinger model and the sine-Gordon model (at the Luther-Emery point and in the semiclassical approximation) after a quantum quench is studied. We compute in detail one and two-point correlation functions for different types of quenches: from a non-interacting to an interacting Luttinger model and vice-versa, and from the gapped to the gapless phase of the sine-Gordon model and vice-versa. A progressive destruction of the Fermi gas features in the momentum distribution is...

Source: http://arxiv.org/abs/0903.1205v2

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29

Sep 23, 2013
09/13

by
Hichem Hajaiej

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For a large class of supermodular integrands, we establish conditions under which balls are the unique (up to translations) maximizers of the Riesz-type functionals with constraints.

Source: http://arxiv.org/abs/0903.2821v1

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38

Sep 23, 2013
09/13

by
V. Soltan

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Extending results of Suss and Hadwiger (proved by them for the case of convex bodies and positive ratios), we show that compact (respectively, closed) convex sets in the Euclidean space of dimension n are homothetic provided for any given integer m between 2 and n - 1 (respectively, between 3 and n - 1), the orthogonal projections of the sets on every m-dimensional plane are homothetic, where homothety ratio and its sign may depend on the projection plane. The proof uses a refined version of...

Source: http://arxiv.org/abs/0903.2836v1

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27

Sep 21, 2013
09/13

by
Larry Guth

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Let M be a closed 3-manifold which can be triangulated with N simplices. We prove that any map from M to a genus 2 surface has Hopf invariant at most C^N. Let X be a closed oriented hyperbolic 3-manifold with injectivity radius less than epsilon at one point. If there is a degree non-zero map from M to X, then we prove that epsilon is at least C^{-N}.

Source: http://arxiv.org/abs/0709.1247v2

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Sep 21, 2013
09/13

by
J. M. Drummond; J. M. Henn

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We give an explicit formula for all tree amplitudes in N=4 SYM, derived by solving the recently presented supersymmetric tree-level recursion relations. The result is given in a compact, manifestly supersymmetric form and we show how to extract from it all possible component amplitudes for an arbitrary number of external particles and any arrangement of external particles and helicities. We focus particularly on extracting gluon amplitudes which are valid for any gauge theory. The formula for...

Source: http://arxiv.org/abs/0808.2475v4

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Sep 23, 2013
09/13

by
Mario I. Molina; Yuri S. Kivshar

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We study two-color surface solitons in two-dimensional photonic lattices with quadratic nonlinear response. We demonstrate that such parametrically coupled optical localized modes can exist in the corners or at the edges of a square photonic lattice, and we analyze the impact of the phase mismatch on their properties, stability, and the threshold power for their generation.

Source: http://arxiv.org/abs/0903.2858v1

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Sep 23, 2013
09/13

by
Tomoko Mizuguchi; Takashi Odagaki

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A monatomic simple liquid in two dimensions, where atoms interact isotropically through the Lennard-Jones-Gauss potential [M. Engel and H.-R. Trebin, Phys. Rev. Lett. 98, 225505 (2007)], is vitrified by the use of a rapid cooling technique in a molecular dynamics simulation. Transformation to a crystalline state is investigated at various temperatures and the time-temperature-transformation (TTT) curve is determined. It is found that the transformation time to a crystalline state is the...

Source: http://arxiv.org/abs/0903.2333v2

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25

Sep 23, 2013
09/13

by
Xiaoyu Jiao; Yuan Gao; S. Y. Lou

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An approximate homotopy symmetry method for nonlinear problems is proposed and applied to the six-order boussinesq equation. We summarize the general formulas for similarity reduction solutions and similarity reduction equations of different orders, educing the related homotopy series solutions. The convergence region of homotopy series solutions can be adjusted by the auxiliary parameter. Series solutions and similarity reduction equations from approximate symmetry method can be retrieved from...

Source: http://arxiv.org/abs/0903.2703v1

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Sep 23, 2013
09/13

by
Yudi Santoso

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We review the phenomenology of gravitino dark matter within supergravity framework. Gravitino can be dark matter if it is the lightest supersymmetric particle, which is stable if R-parity is conserved. There are several distinct scenarios depending on what the next to lightest supersymmetric particle (NLSP) is. We discuss the constraints and summarize the phenomenology of neutralino, stau, stop and sneutrino NLSPs.

Source: http://arxiv.org/abs/0903.2860v1

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Sep 23, 2013
09/13

by
G. van Harten; F. Snik; C. U. Keller

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In polarimetry it is important to characterize the polarization properties of the instrument itself to disentangle real astrophysical signals from instrumental effects. This article deals with the accurate measurement and modeling of the polarization properties of real aluminum mirrors, as used in astronomical telescopes. Main goals are the characterization of the aluminum oxide layer thickness at different times after evaporation and its influence on the polarization properties of the mirror....

Source: http://arxiv.org/abs/0903.2740v1

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45

Sep 23, 2013
09/13

by
A. S. Vardanyan; A. A. Kteyan; R. A. Vardanyan

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Within the framework of McLaughlin-Scott perturbation theory the equation-of-motion of the dislocation kink in the pinning potential is linearized, assuming the simultaneous influence of ac and dc forces. Based on the equations derived, the probability of kink depinning was studied. The dependencies of the depinning probability on dc and ac forces are analyzed in details.

Source: http://arxiv.org/abs/0903.2700v1

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21

Sep 23, 2013
09/13

by
David J. Grynkiewicz; Luz Elimar Marchan; Oscar Ordaz

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Let $G$ be a finite abelian group and let $A\subseteq \mathbb{Z}$ be nonempty. Let $D_A(G)$ denote the minimal integer such that any sequence over $G$ of length $D_A(G)$ must contain a nontrivial subsequence $s_1... s_r$ such that $\sum_{i=1}^{r}w_is_i=0$ for some $w_i\in A$. Let $E_A(G)$ denote the minimal integer such that any sequence over $G$ of length $E_A(G)$ must contain a subsequence of length $|G|$, $s_1... s_{|G|}$, such that $\sum_{i=1}^{|G|}w_is_i=0$ for some $w_i\in A$. In this...

Source: http://arxiv.org/abs/0903.2810v1

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Sep 22, 2013
09/13

by
A. Y. Abul-Magd; G. Akemann; P. Vivo

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Using Beck and Cohen's superstatistics, we introduce in a systematic way a family of generalised Wishart-Laguerre ensembles of random matrices with Dyson index $\beta$ = 1,2, and 4. The entries of the data matrix are Gaussian random variables whose variances $\eta$ fluctuate from one sample to another according to a certain probability density $f(\eta)$ and a single deformation parameter $\gamma$. Three superstatistical classes for $f(\eta)$ are usually considered: $\chi^2$-, inverse $\chi^2$-...

Source: http://arxiv.org/abs/0811.1992v2

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Sep 23, 2013
09/13

by
Martin Lorenz

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We develop the theory of rational ideals for arbitrary associative algebras R without assuming the standard finiteness conditions, noetherianness or the Goldie property. The Amitsur-Martindale ring of quotients replaces the classical ring of quotients which underlies the previous definition of rational ideals but is not available in a general setting. Our main result concerns rational actions of an affine algebraic group G on R. Working over an algebraically closed base field, we prove an...

Source: http://arxiv.org/abs/0801.3472v3

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Sep 18, 2013
09/13

by
A. Bourque; C. Gale

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An alternative model for the dissociation of the J/psi is proposed. Chiral symmetry is properly implemented. Abnormal parity interactions and mesonic form factors naturally arise from the underlying quark sub-structure. Analytic confinement for the light quarks is generated by appropriately chosen the quark interaction kernels. Dissociation cross sections of the J/psi by either a pion or a rho meson are then evaluated and discussed.

Source: http://arxiv.org/abs/0809.3955v2

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Sep 23, 2013
09/13

by
Xiang Hao; Tao Pan; Taocheng Zang; Shiqun Zhu

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he multiqubit entangled states are coherently controlled in the quantum spin systems composed of $N+1$ interacting antiferromagnetic molecular rings. The tunable intermolecular couplings arise from the local exchange interactions between electron spins of $N$ circumjacent magnets and those of one central molecular ring. The quantum dynamics of such system is analytically deduced by the effective spin hamiltonian with anisotropic Heisenberg couplings. It is found that entangled $W$ states can be...

Source: http://arxiv.org/abs/0903.2705v1

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Sep 23, 2013
09/13

by
Stephen Kent; Mary Elizabeth Kaiser; Susana E. Deustua; J. Allyn Smith; Saul Adelman; Sahar Allam; Brian Baptista; Ralph C. Bohlin; James L. Clem; Alex Conley; Jerry Edelstein; Jay Elias; Ian Glass; Arne Henden; Steve Howell; Randy A. Kimble; Jeffrey W. Kruk; Michael Lampton; Eugene A. Magnier; Stephan R. McCandliss; Warren Moos; Nick Mostek; Stuart Mufson; Terry D. Oswalt; Saul Perlmutter; Carlos Allende Prieto; Bernard J. Rauscher; Adam Riess; Abhijit Saha; Mark Sullivan; Nicholas Suntzeff; Alan Tokunaga; Douglas Tucker; Robert Wing; Bruce Woodgate; Edward L. Wright

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The answers to fundamental science questions in astrophysics, ranging from the history of the expansion of the universe to the sizes of nearby stars, hinge on our ability to make precise measurements of diverse astronomical objects. As our knowledge of the underlying physics of objects improves along with advances in detectors and instrumentation, the limits on our capability to extract science from measurements is set, not by our lack of understanding of the nature of these objects, but rather...

Source: http://arxiv.org/abs/0903.2799v1

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Sep 23, 2013
09/13

by
P. Fritsch; S. Kehrein

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We derive a consistent 2-loop scaling picture for a Kondo dot in both equilibrium and non-equilibrium situations using the flow equation method. Our analysis incorporates the important decoherence effects from both thermal and non-equilibrium noise in a common setting. We calculate the spin-spin correlation function, the T-matrix, and the magnetization as functions of applied magnetic field, dc-voltage bias and temperature. In all these quantities we observe characteristic non-equilibrium...

Source: http://arxiv.org/abs/0903.2865v1

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Sep 23, 2013
09/13

by
O Foda; M Wheeler; M Zuparic

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Using a Jacobi-Trudi-type identity, we show that the scalar product of a general state and a Bethe eigenstate in a finite-length XXZ spin-1/2 chain is (a restriction of) a KP tau function. This leads to a correspondence between the eigenstates and points on Sato's Grassmannian. Each of these points is a function of the rapidities of the corresponding eigenstate, the inhomogeneity variables of the spin chain and the crossing parameter.

Source: http://arxiv.org/abs/0903.2611v1

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Sep 23, 2013
09/13

by
S. J. George; C. H. Ishwara-Chandra

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We present results of deep 150 MHz observations with the GMRT which show several extended radio sources with a range of morphologies. These sources have then further followed up at higher frequencies (610 and 1400 MHz) with the GMRT. GMRT J0137+4121 was a candidate double--double radio galaxy for which we have also used the VLA-A array at C band to resolve the core. These observations have allowed us to determine that this source is a normal radio galaxy with a core and a one sided jet....

Source: http://arxiv.org/abs/0903.2726v1

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Sep 23, 2013
09/13

by
Iskren Y. Georgiev; Michael Hilker; Thomas H. Puzia; Paul Goudfrooij; Holger Baumgardt

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(Abridged) Using luminosities and structural parameters of globular clusters (GCs) in the nuclear regions (nGCs) of low-mass dwarf galaxies from HST/ACS imaging we derive the present-day escape velocities (v_esc) of stellar ejecta to reach the cluster tidal radius and compare them with those of Galactic GCs with extended (hot) horizontal branches (EHBs-GCs). For EHB-GCs, we find a correlation between the present-day v_esc and their metallicity as well as (V-I)_0 colour. The similar v_esc,...

Source: http://arxiv.org/abs/0903.2857v1

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Sep 23, 2013
09/13

by
Alexander Makin

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We consider the spectral problem generated by the Sturm-Liouville equation with an arbitrary complex-valued potential q(x) and irregular boundary conditions. We establish necessary and sufficient conditions for a set of complex numbers to be the spectrum of such an operator.

Source: http://arxiv.org/abs/0903.2699v1

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Sep 23, 2013
09/13

by
Frédéric Klopp; Shu Nakamura

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We study Lifshitz tails for random Schr\"odinger operators where the random potential is alloy type in the sense that the single site potentials are independent, identically distributed, but they may have various function forms. We suppose the single site potentials are distributed in a finite set of functions, and we show that under suitable symmetry conditions, they have Lifshitz tail at the bottom of the spectrum except for special cases. When the single site potential is symmetric with...

Source: http://arxiv.org/abs/0903.2105v2

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Sep 20, 2013
09/13

by
Rasmus Villemoes

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Given a set equipped with a transitive action of a group, we define the notion of an almost invariant coloring of the set. We consider the mapping class group orbit of a multicurve on a compact surface, and prove that in the case of genus at least two, no such almost invariant coloring exists. Conversely, in the case of a closed torus, one may find almost invariant colorings using arbitrarily many colors.

Source: http://arxiv.org/abs/0802.3000v2

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Sep 21, 2013
09/13

by
Shin-ichi Kato; Keiji Takano

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A symmetric space analogue of Casselman's criterion for square integrability of representations of a p-adic group is established. It is described in terms of exponents of Jacquet modules along parabolic subgroups associated to the symmetric space.

Source: http://arxiv.org/abs/0902.2302v2

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Sep 23, 2013
09/13

by
Frans Snik; Theodora Karalidi; Christoph U. Keller

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Linear (spectro) polarimetry is usually performed using separate photon flux measurements after spatial or temporal polarization modulation. Such classical polarimeters are limited in sensitivity and accuracy by systematic effects and noise. We describe a spectral modulation principle that is based on encoding the full linear polarization properties of light in its spectrum. Such spectral modulation is obtained with an optical train of an achromatic quarter-wave retarder, an athermal...

Source: http://arxiv.org/abs/0903.2735v1

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Sep 23, 2013
09/13

by
Javier Cilleruelo; D. S. Ramana; Olivier Ramare

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When $A$ and $B$ are subsets of the integers in $[1,X]$ and $[1,Y]$ respectively, with $|A| \geq \alpha X$ and $|B| \geq \beta X$, we show that the number of rational numbers expressible as $a/b$ with $(a,b)$ in $A \times B$ is $\gg (\alpha \beta)^{1+\epsilon}XY$ for any $\epsilon > 0$, where the implied constant depends on $\epsilon$ alone. We then construct examples that show that this bound cannot in general be improved to $\gg \alpha \beta XY$. We also resolve the natural generalisation...

Source: http://arxiv.org/abs/0903.2714v1

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Sep 23, 2013
09/13

by
Kang Ning

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The DNA cryptography is a new and very promising direction in cryptography research. DNA can be used in cryptography for storing and transmitting the information, as well as for computation. Although in its primitive stage, DNA cryptography is shown to be very effective. Currently, several DNA computing algorithms are proposed for quite some cryptography, cryptanalysis and steganography problems, and they are very powerful in these areas. However, the use of the DNA as a means of cryptography...

Source: http://arxiv.org/abs/0903.2693v1

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Sep 23, 2013
09/13

by
Luigi Secco; Daniele Bindoni

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The theory of the Clausius' virial maximum to explain the Fundamental Plane (FP) proposed by Secco (2000, 2001,2005) is based on the existence of a maximum in the Clausius' Virial (CV) potential energy of a early type galaxy (ETG) stellar component when it is completely embedded inside a dark matter (DM) halo. At the first order approximation the theory was developed by modeling the two-components with two cored power-law density profiles. An higher level of approximation is now taken into...

Source: http://arxiv.org/abs/0903.2762v1

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57

Sep 23, 2013
09/13

by
Yann Bugeaud; Bernard De Mathan

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Let $d$ be a positive integer. Let $p$ be a prime number. Let $\alpha$ be a real algebraic number of degree $d+1$. We establish that there exist a positive constant $c$ and infinitely many algebraic numbers $\xi$ of degree $d$ such that $|\alpha - \xi| \cdot \min\{|\Norm(\xi)|_p,1\} < c H(\xi)^{-d-1} (\log 3 H(\xi))^{-1/d}$. Here, $H(\xi)$ and $\Norm(\xi)$ denote the na{\"\i}ve height of $\xi$ and its norm, respectively. This extends an earlier result of de Mathan and Teuli\'e that...

Source: http://arxiv.org/abs/0903.2741v1

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Sep 23, 2013
09/13

by
Carl Pomerance; Igor E. Shparlinski

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We show that the average and typical ranks in a certain parametric family of elliptic curves described by D. Ulmer tend to infinity as the parameter $d \to\infty$. This is perhaps unexpected since by a result of A. Brumer, the average rank for all elliptic curves over a function field of positive characteristic is asymptotically bounded above by 2.3.

Source: http://arxiv.org/abs/0903.2866v1

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Sep 23, 2013
09/13

by
Lianfeng Long; Changming Xiao

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Combined with the principle of entropy maximum and CS state equation, the critical size for a cluster to nucleate then the critical volume fraction of a phase transition is determined in this paper, and our result is in good agreement with the experiments. Furthermore, no parameter is introduced in the discussion.

Source: http://arxiv.org/abs/0903.2698v1