arXiv papers from August 2007

Dragos Oprea

We study the splitting properties of the Verlinde bundles over elliptic curves. Our methods rely on the explicit description of the moduli space of semistable vector bundles on elliptic curves, and on the analysis of the symmetric powers of the Schrodinger representation of the Theta group.

J. Michael Shull

The first massive stars may influence the formation of second-generation stars, in part by their metal enrichment of the surrounding gas. We investigate the "critical metallicity", defined as the the value, Z_crit, at which primordial gas cools more efficiently by fine-structure lines of O I (63.18 microns, Si II 34.8 microns, Fe II (25.99 and 35.35 microns)

K. Jorissen, J. J. Rehr

{\it Ab initio} calculations of relativistic electron energy loss spectra (REELS) are carried out using a generalization of the real-space Green's function code FEFF8 which is applicable to general aperiodic materials. Our approach incorporates relativistic effects in terms of the cross-section tensor within the dipole selection rule. In particular the appro

Francis N. C. Paraan, Mikhail P. Solon, J. P. Esguerra

We give an exact solution to the generalized Langevin equation of motion of a charged Brownian particle in a uniform magnetic field that is driven internally by an exponentially-correlated stochastic force. A strong dissipation regime is described in which the ensemble-averaged fluctuations of the velocity exhibit transient oscillations that arise from memor

Kristjan Haule, Gabriel Kotliar

We use cluster Dynamical Mean Field Theory to study the simplest models of correlated electrons, the Hubbard model and the t-J model. We use a plaquette embedded in a medium as a reference frame to compute and interpret the physical properties of these models. We study various observables such as electronic lifetimes, one electron spectra, optical conductivi

Tiago Jose Arruda, Rodrigo Silva Gonzalez, Cesar Augusto Sangaletti Tercariol, Alexandre Souto Martinez

One-parameter generalizations of the logarithmic and exponential functions have been obtained as well as algebraic operators to retrieve extensivity. Analytical expressions for the successive applications of the sum or product operators on several values of a variable are obtained here. Applications of the above formalism are considered.

S. Ahmad, H. Honkanen, S. Liuti, S. K. Taneja

We propose a physically motivated parametrization for the unpolarized generalized parton distributions, H and E, valid at both zero and non-zero values of the skewness variable, \zeta. At \zeta=0, H and E are determined using constraints from simultaneous fits of experimental data on both the nucleon elastic form factors and the deep inelastic structure func

Guglielmo Fucci, Ivan G. Avramidi

We study a noncommutative deformation of general relativity where the gravitational field is described by a matrix-valued symmetric two-tensor field. The equations of motion are derived in the framework of this new theory by varying a diffeomorphisms and gauge invariant action constructed by using a matrix-valued scalar curvature. Interestingly the genuine n

Bindiya Arora, M. S. Safronova, Charles W. Clark

Stark shifts of potassium and rubidium D1 lines have been measured with high precision by Miller et al [1]. In this work, we combine these measurements with our all-order calculations to determine the values of the electric-dipole matrix elements for the 4p_j-3d_j' transitions in K and for the 5p_j-4d_j' transitions in Rb to high precision. The 4p_1/2-3d_3/2

Roman Romanov, Michael Tihomirov

The aim of the paper is to obtain a description of the selfadjoint subspace of the one-speed Boltzmann operator. It is proved that this subspace is nontrivial if the collision integral is polynomial and the multiplication coefficient has a lattice of gaps. A similar result is shown to hold for the 3-dimensional transport operator. Keywords: completely nonsel

C. Ryu, M. F. Andersen, P. Clade, Vasant Natarajan

We have observed the persistent flow of Bose-condensed atoms in a toroidal trap. The flow persists without decay for up to 10 s, limited only by experimental factors such as drift and trap lifetime. The quantized rotation was initiated by transferring one unit, $\hbar$, of the orbital angular momentum from Laguerre-Gaussian photons to each atom. Stable flow

Mihai Popa

The present material addresses several problems left open in the Trans. AMS paper " Non-crossing cumulants of type B" of P. Biane, F. Goodman and A. Nica. The main result is that a type B non-commutative probability space can be studied in the framework of freeness with amalgamation. This view allows easy ways of constructing a version of the S-transform as

E. M. Becerra-Castro, W. B. Cardoso, A. T. Avelar, B. Baseia

A recent work [1] proposed a type of cluster entangled coherent states and its generation. Here we present an alternative experimental arrangement for its generation in bimodal QED cavities. The scheme employs a single two-level atom that interacts dispersively with cavity modes initially prepared in coherent states. The fidelity and success probability of t

Scott F. Daniel, Robert R. Caldwell

The classical gravitational theory of a scalar field with a gradient coupling to the Ricci tensor is examined. This is a scalar-vector-tensor gravitational theory, but in the case that the coupling is weak and the scalar evolves like a quintessence field on cosmological time scales, the field equations within the solar system are similar to a vector-tensor t

J. R. Maund, J. C. Wheeler, F. Patat, D. Baade

The observational technique of spectropolarimetry has been used to directly measure the asymmetries of Supernovae (SNe), Gamma-Ray Bursts (GRBs) and X-Ray Flashes (XRFs). We wish to determine if non-axial asymmetries are present in SNe that are associated with GRBs and XRFs, given the particular alignment of the jet axis and axis of symmetry with the line of

Subhasish Basak, R. G. Edwards, G. T. Fleming, K. J. Juge

Energies for excited isospin I=1/2 and I=3/2 states that include the nucleon and Delta families of baryons are computed using quenched, anisotropic lattices. Baryon interpolating field operators that are used include nonlocal operators that provide G_2 irreducible representations of the octahedral group. The decomposition of spin 5/2 or higher spin states is

Kaustubh Agashe, Hooman Davoudiasl, Shrihari Gopalakrishna, Tao Han

We study signals at the Large Hadron Collider (LHC) for Kaluza-Klein (KK) excitations of the electroweak gauge bosons in the framework with the Standard Model (SM) gauge and fermion fields propagating in a warped extra dimension. Such a framework addresses both the Planck-weak and flavor hierarchy problems of the SM. Unlike the often studied Z' cases, in thi

Carlos A. Perez-Delgado, Donny Cheung

In this paper we present a quantization of Cellular Automata. Our formalism is based on a lattice of qudits, and an update rule consisting of local unitary operators that commute with their own lattice translations. One purpose of this model is to act as a theoretical model of quantum computation, similar to the quantum circuit model. It is also shown to be

Dimitri Veras

Investigations of two resonant planets orbiting a star or two resonant satellites orbiting a planet often rely on a few resonant and secular terms in order to obtain a representative quantitative description of the system's dynamical evolution. We present a semianalytic model which traces the orbital evolution of any two resonant bodies in a first- through f

Cedric Deffayet, Kristen Menou

A gravitational observatory such as LISA will detect coalescing pairs of massive black holes, accurately measure their luminosity distance and help identify a host galaxy or an electromagnetic counterpart. If dark energy is a manifestation of modified gravity on large scales, gravitational waves from cosmologically-distant spacetime sirens are direct probes

C. A. Lamas

The two-dimensional Hubbard model on the square lattice is studied in the presence of lattice distortions in the adiabatic approximation. The self energy is computed within perturbation theory up to second order, which provides a way for studying the quasiparticle dispersion. We compute numerically the second order contribution to the self-energy using a sta

Axel Krause

It is shown that multi M5-brane inflation in heterotic M-theory gives rise to a detectable gravitational wave power spectrum with tensor fraction $r$ typically larger than the projected experimental sensitivity, $r_{exp} = 0.01$. A measurable gravitational wave power spectrum entails a large inflationary energy scale and a super-Planckian inflaton variation.

Marcelo Alves Pereira, Alexandre Souto Martinez, Aquino Lauri Espindola

The Prisoner's Dilemma (PD) is one of the most popular games of the Game Theory due to the emergence of cooperation among competitive rational players. In this paper, we present the PD played in cells of one-dimension cellular automata, where the number of possible neighbors that each cell interacts, z, can vary. This makes possible to retrieve results obtai

Andrei Lobanov

VLBI observations of relativistic outflows (jets) in galactic nuclei, complemented with detailed studies made in other spectral domains, have become an effective tool for investigating the physics of nuclear regions in galaxies. High-resolution radio observations access directly the regions where the jets are formed, and trace their evolution and interaction

L. Cerrigone, J. L. Hora, G. Umana, C. Trigilio

IC 4406 is a large (about 100'' x 30'') southern bipolar planetary nebula, composed by two elongated lobes, extending from a bright central region, where there is evidence for the presence of a large torus of gas and dust. In this poster we show new observations of this source performed with IRAC (Spitzer Space Telescope) and the Australia Telescope Compact

Shahram M. Shahruz

In this paper, a methodology for designing efficient energy scavengers is proposed. The scavenger consists of a cantilever beam on which piezoelectric films and a mass are mounted. The mass at the tip of the beam is known as the proof mass and the device is called either an energy scavenger or a beam-mass system. The proof mass is a permanent magnet, where i

Werner Vogelsang, Feng Yuan

We compare several recent theoretical studies of the single transverse spin asymmetry in dijet-correlations at hadron colliders. We show that the results of these studies are all consistent. To establish this, we investigate in particular the two-gluon exchange contributions to the relevant initial and final state interactions in the context of a simplifying

John Collins

A previous counterexample to disprove k_T-factorization for H_1+H_2 --> H_3+H_4+X is extended calculationally to one higher order in gluon exchange. The result is that, by explicit calculation, standard k_T-factorization fails for the unpolarized cross-section for the production of hadrons of high transverse momentum in hadron-hadron collisions.

L. DeBeer-Schmitt, M. R. Eskildsen, M. Ichioka, K. Machida

The magnetic field distribution around the vortices in TmNi2B2C in the paramagnetic phase was studied experimentally as well as theoretically. The vortex form factor, measured by small-angle neutron scattering, is found to be field independent up to 0.6 Hc2 followed by a sharp decrease at higher fields. The data are fitted well by solutions to the Eilenberge

W. G. Roberge, Glenn E. Ciolek

We study the physics of wave propagation in a weakly ionised plasma, as it applies to the formation of multifluid, MHD shock waves. We model the plasma as separate charged and neutral fluids which are coupled by ion-neutral friction. At times much less than the ion-neutral drag time, the fluids are decoupled and so evolve independently. At later times, the e

Amy Glen, Jacques Justin, Giuseppe Pirillo

In this paper, we characterize by lexicographic order all finite Sturmian and episturmian words, i.e., all (finite) factors of such infinite words. Consequently, we obtain a characterization of infinite episturmian words in a "wide sense" (episturmian and episkew infinite words). That is, we characterize the set of all infinite words whose factors are (finit

Mathias Becker, Wolfgang Konig

Consider an arbitrary transient random walk on $\Z^d$ with $d\in\N$. Pick $\alpha\in[0,\infty)$ and let $L_n(\alpha)$ be the spatial sum of the $\alpha$-th power of the $n$-step local times of the walk. Hence, $L_n(0)$ is the range, $L_n(1)=n+1$, and for integers $\alpha$, $L_n(\alpha)$ is the number of the $\alpha$-fold self-intersections of the walk. We pr

G. Susinder Rajan, B. Sundar Rajan

The differential encoding/decoding setup introduced by Kiran et al, Oggier-Hassibi and Jing-Jafarkhani for wireless relay networks that use codebooks consisting of unitary matrices is extended to allow codebooks consisting of scaled unitary matrices. For such codebooks to be usable in the Jing-Hassibi protocol for cooperative diversity, the conditions involv

Amy Glen

To any infinite word w over a finite alphabet A we can associate two infinite words min(w) and max(w) such that any prefix of min(w) (resp. max(w)) is the lexicographically smallest (resp. greatest) amongst the factors of w of the same length. We say that an infinite word w over A is "fine" if there exists an infinite word u such that, for any lexicographic

Ilia Gogoladze, Nobuchika Okada, Qaisar Shafi

Unparticle physics from a hidden conformal sector can alter the evolution of the Standard Model (SM) gauge couplings via TeV scale threshold corrections. We discuss how this may lead to gauge coupling unification at M_{GUT}\approx 2 \times 10^{15} GeV -- 5 \times 10^{17} GeV without introducing new particles in the SM sector.

Sash Sarangi, Gary Shiu, Benjamin Shlaer

Motivated by the possibility of a string landscape, we reexamine tunneling of a scalar field across single/multiple barriers. Recent investigations have suggested modifications to the usual picture of false vacuum decay that lead to efficient and rapid tunneling in the landscape when certain conditions are met. This can be due to stringy effects (e.g. tunnel

Sergey Arkhipov, Kobi Kremnizer

We construct a central extension of the group of automorphisms of a 2-Tate vector space viewed as a discrete 2-group. This is done using an action of this 2-group on a 2-gerbe of gerbel theories. This central extension is used to define central extensions of double loop groups.

S. Hesselbach, S. Moretti, J. Rathsman, A. Sopczak

We report on detailed Monte Carlo comparisons of selection variables to separate tbH+ signal events from the Standard Model ttbar background using an Iterative Discriminant Analysis (IDA) method. While kinematic differences exist between the two processes whenever m(H+).ne.m(W+), the exploration of the spin difference between the charged Higgs and the W+ gau

Svante Janson

It is shown that in a subcritical random graph with given vertex degrees satisfying a power law degree distribution with exponent $\gamma>3$, the largest component is of order $n^{1/(\gamma-1)}$. More precisely, the order of the largest component is approximatively given by a simple constant times the largest vertex degree. These results are extended to seve

Rosa M. Torres, Laurent Loinard, Amy J. Mioduszewski, Luis F. Rodriguez

The non-thermal 3.6 cm radio continuum emission from the naked T Tauri stars Hubble 4 and HDE 283572 in Taurus has been observed with the Very Long Baseline Array (VLBA) at 6 epochs between September 2004 and December 2005 with a typical separation between successive observations of 3 months. Thanks to the remarkably accurate astrometry delivered by the VLBA

S. -H. Henry Tye

In an earlier paper, it is proposed that, due to resonance tunneling effect, tunneling from a large cosmological constant $\Lambda$ site in the stringy comic landscape can be fast, while tunneling from a small $\Lambda$ site may take exponentially long time. Borrowing the renormalization group analysis of the conductance in the Anderson localization transiti

Amy Glen

This paper concerns a specific class of strict standard episturmian words whose directive words resemble those of characteristic Sturmian words. In particular, we explicitly determine all integer powers occurring in such infinite words, extending recent results of Damanik and Lenz (2003), who studied powers in Sturmian words. The key tools in our analysis ar

Kostas Triantafyllopoulos, Giovanni Montana

In this paper we develop a Bayesian procedure for estimating multivariate stochastic volatility (MSV) using state space models. A multiplicative model based on inverted Wishart and multivariate singular beta distributions is proposed for the evolution of the volatility, and a flexible sequential volatility updating is employed. Being computationally fast, th

Ping-Shun Chan, Yuval Z. Flicker

Let E/F be a quadratic number (resp. p-adic) field extension, and F' an odd degree cyclic field extension of F. We establish a base-change functorial lifting of automorphic (resp. admissible) representations from the unitary group U(3,E/F) associated with E/F to the unitary group U(3,F'E/F'). As a consequence, we classify the invariant packets of U(3,F'E/F')

John T. Stocke, Charles W. Danforth, J. Michael Shull, Steven V. Penton

We have used the Hubble/STIS and FUSE archives of ultraviolet spectra of bright AGN to identify intergalactic Lya absorbers in nearby (z < 0.1) voids. From a parent sample of 651 Lya absorbers, we identified 61 void absorbers located more than 1.4/h_70 Mpc from the nearest L* or brighter galaxy. Searching for metal absorption in high-quality (S/N > 10) spect

Alberto Canonaco, Matthias Kuenzer

Suppose given a commutative quadrangle in a Verdier triangulated category such that there exists an induced isomorphism on the horizontally taken cones. Suppose that the endomorphism ring of the initial or the terminal corner object of this quadrangle satisfies a finiteness condition. Then this quadrangle is homotopy cartesian.

Karl Rökaeus

We establish a formula for the classes of certain tori in the Grothendieck ring of varieties, in terms of its lambda-structure. More explicitly, we will see that if L* is the torus of invertible elements in the n-dimensional separable k-algebra L, then the class of L* can be expressed as an alternating sum of the images of the spectrum of L under the lambda-

Ivan S. Terekhov, Alexander I. Milstein, Valeri N. Kotov, Oleg P. Sushkov

We calculate exactly the vacuum polarization charge density in the field of a subcritical Coulomb impurity, $Z|e|/r$, in graphene. Our analysis is based on the exact electron Green's function, obtained by using the operator method, and leads to results that are exact in the parameter $Z\alpha$, where $\alpha$ is the "fine structure constant" of graphene. Tak

Johan Lagerqvist, Michael Zwolak, Massimiliano Di Ventra

We study theoretically the feasibility of using transverse electronic transport within a nanopore for rapid DNA sequencing. Specifically, we examine the effects of the environment and detection probes on the distinguishability of the DNA bases. We find that the intrinsic measurement bandwidth of the electrodes helps the detection of single bases by averaging

David P. Huenemoerder, Joel H. Kastner, Paola Testa, Norbert S. Schulz

We present high-resolution X-ray spectra of the multiple T Tauri star system Hen 3-600, obtained with the High Energy Transmission Grating Spectrograph on the Chandra X-ray Observatory. Two binary components were detected in the zeroth-order image. Hen 3-600-A, which has a large mid-infrared excess, is a 2-3 times fainter in X-rays than Hen 3-600-B, due to a

Raymond Hemmecke, Kristen A. Nairn

In this paper we show that if for an integer matrix A the universal Gr\"obner basis of the associated toric ideal \Ideal_A coincides with the Graver basis of A, then the Gr\"obner complexity u(A) and the Graver complexity g(A) of its higher Lawrence liftings agree, too. We conclude that for the matrices A_{3\times 3} and A_{3\times 4}, defining the 3\times 3

Janko Boehm

Using tropical geometry we propose a mirror construction for monomial degenerations of Calabi-Yau varieties in toric Fano varieties. The construction reproduces the mirror constructions by Batyrev for Calabi-Yau hypersurfaces and by Batyrev and Borisov for Calabi-Yau complete intersections. We apply the construction to Pfaffian examples and recover the mirro

Wayne Hu, Daniel E. Holz, Chris Vale

We discuss combining gravitational lensing of galaxies and the cosmic microwave background (CMB) by clusters to measure cosmographic distance ratios, and hence dark energy parameters. Advantages to using the CMB as the second source plane, instead of galaxies, include: a well-determined source distance, a longer lever arm for distance ratios, typically up to

Bjoern S. Schmekel

The problem of defining energy in general relativity is reviewed very briefly, and the properties of Brown-York-like expressions are discussed.

Oluseyi Latunde-Dada

This paper describes the MC@NLO method for matching next-to-leading order (NLO) perturbative QCD with the parton shower and hadronization model of the Monte Carlo (MC) event generator tt Herwig++, for e+e- annihilation and Drell-Yan lepton pair production. Details of the event generation method as well as spin, flavour, momentum and colour assignments are pr

Amy Glen

This paper is concerned with palindromes occurring in characteristic Sturmian words $c_\alpha$ of slope $\alpha$, where $\alpha \in (0,1)$ is an irrational. As $c_\alpha$ is a uniformly recurrent infinite word, any (palindromic) factor of $c_\alpha$ occurs infinitely many times in $c_\alpha$ with bounded gaps. Our aim is to completely describe where palindro

Amy Glen

This article is concerned with characteristic Sturmian words of slope $\alpha$ and $1-\alpha$ (denoted by $c_\alpha$ and $c_{1-\alpha}$ respectively), where $\alpha \in (0,1)$ is an irrational number such that $\alpha = [0;1+d_1,\bar{d_2,...,d_n}]$ with $d_n \geq d_1 \geq 1$. It is known that both $c_\alpha$ and $c_{1-\alpha}$ are fixed points of non-trivial

Amanda I. Karakas, John C. Lattanzio

We present stellar yields calculated from detailed models of low and intermediate-mass asymptotic giant branch (AGB) stars. We evolve models with a range of mass from 1 to 6Msun, and initial metallicities from solar to 1/200th of the solar metallicity. Each model was evolved from the zero age main sequence to near the end of the thermally-pulsing AGB phase,

M. Cantiello, H. Hoekstra, N. Langer, A. J. T. Poelarends

Thermohaline mixing has recently been proposed to occur in low mass red giants, with large consequence for the chemical yields of low mass stars. We investigate the role of thermohaline mixing during the evolution of stars between 1 Msun and 3 Msun. We use a stellar evolution code which includes rotational mixing and internal magnetic fields. We confirm that

Jurgen Reuter

We investigate the potential of the ILC for measuring anomalous quartic gauge couplings, both in production of three electroweak gauge bosons as well as in vector boson scattering. Any new physics that could possibly couple to the electroweak gauge bosons is classified according to its spin and isospin quantum numbers and parameterized in terms of resonance

Lars Rindorf, Ole Bang

We study the sensitivity of fiber grating sensors in the applications of strain, temperature, internal label-free biosensing, and internal refractive index sensing. It is shown that optical dispersion plays a central role in determining the sensitivity, and the dispersion may enhance or suppress sensitivity as well as change the sign of the resonant waveleng

V. Kharlamov, Vik. Kulikov

The automorphism group of the Galois covering induced by a pluri-canonical generic covering of a projective space is investigated. It is shown that by means of such coverings one obtains, in dimensions one and two, serieses of specific actions of the symmetric groups $S_d$ on curves and surfaces not deformable to an action of $S_d$ which is not the full auto

Bianca M. Mladek, Gerhard Kahl, Christos N. Likos

Recent theoretical studies have predicted a new clustering mechanism for soft matter particles that interact via a certain kind of purely repulsive, bounded potentials. At sufficiently high densities, clusters of overlapping particles are formed in the fluid, which upon further compression crystallize into cubic lattices with density-independent lattice cons

Marisa Debowsky, Adrian Riskin

We describe a new system for the simulation of simultaneous moves between noncolocational players. This has applications in the burgeoning Rock-Paper-Scissors by mail movement.

Ferdinando Auricchio, Alexander Mielke, Ulisse Stefanelli

This note addresses a three-dimensional model for isothermal stress-induced transformation in shape-memory polycrystalline materials. We treat the problem within the framework of the energetic formulation of rate-independent processes and investigate existence and continuous dependence issues at both the constitutive relation and quasi-static evolution level

E. Vergara-Diaz, C. M. Wood

We study harmonic almost contact structures in the context of contact metric manifolds, and an analysis is carried out when such a manifold fibres over an almost Hermitian manifold, as exemplified by the Boothby-Wang fibration. Two types of almost contact metric warped products are also studied, relating their harmonicity to that of the almost Hermitian stru

Eugen Varvaruca

We study weak solutions for a class of free boundary problems which includes as a special case the classical problem of traveling waves on water of finite depth. We show that such problems are equivalent to problems in fixed domains and study the regularity of their solutions. We also prove that in very general situations the free boundary is necessarily the

Andrea Bordoni, Nicola Manini

We propose an accurate and efficient method to compute vibrational spectra of molecules, based on exact diagonalization of an algebraically calculated matrix based on powers of Morse coordinate. The present work focuses on the 1D potential of diatomic molecules: as typical examples, we apply this method to the standard Lennard-Jones oscillator, and to the ab

Dvira Segal, David R. Reichman, Andrew J. Millis

Dissipative processes in non-equilibrium many-body systems are fundamentally different than their equilibrium counterparts. Such processes are of great importance for the understanding of relaxation in single molecule devices. As a detailed case study, we investigate here a generic spin-fermion model, where a two-level system couples to two metallic leads wi

R. Tonelli

We afford the problem of counting the blocks of a given length made with symbols drawn from an alphabet and relate this number to Fibonacci-like recurrent relations. The recurrence polynomia allows to calculate the limit ratio of two adjacent terms and this information is used to determine the topological entropy of a discrete numbers of associate shift spac

Jacob van den Berg, Antal A. Járai, Bálint Vágvölgyi

We consider invasion percolation on the square lattice. It has been proved by van den Berg, Peres, Sidoravicius and Vares, that the probability that the radius of a so-called pond is larger than n, differs at most a factor of order log n from the probability that in critical Bernoulli percolation the radius of an open cluster is larger than n. We show that t

O. Duran, M. V. N. Silva, L. J. C. Bezerra, H. J. Herrmann

In this work we present measurements of vegetation cover over parabolic dunes with different degree of activation along the north-eastern Brazilian coast. We are able to extend the local values of the vegetation cover density to the whole dune by correlating measurements with the gray-scale levels of a high resolution satellite image of the dune field. The e

P. Astone, D. Babusci, M. Bassan, P. Carelli

The data collected during 2005 by the resonant bar Explorer are divided into segments and incoherently summed in order to perform an all-sky search for periodic gravitational wave signals. The parameter space of the search spanned about 40 Hz in frequency, over 23927 positions in the sky. Neither source orbital corrections nor spindown parameters have been i

M. V. Gorkunov, M. A. Osipov

We propose electrically tunable hybrid metamaterial consisting of special wire grid immersed into nematic liquid crystal. The plasma-like permittivity of the structure can be substantially varied due to switching of the liquid crystal alignment by external voltages applied to the wires. Depending on the scale of the structure, the effect is available for bot

Carl D. Modes, Randall D. Kamien

We examine a simple hard disc fluid with no long range interactions on the two dimensional space of constant negative Gaussian curvature, the hyperbolic plane. This geometry provides a natural mechanism by which global crystalline order is frustrated, allowing us to construct a tractable model of disordered monodisperse hard discs. We extend free area theory

Xuhua He

We will use the combinatorics of the $G$-stable pieces to describe the closure relation of the partition of partial flag varieties in \cite[section 4]{L3}.

Harold Steinacker, Richard J. Szabo

We apply nonabelian equivariant localization techniques to Yang-Mills theory on the fuzzy sphere to write the partition function entirely as a sum over local contributions from critical points of the action. The contributions of the classical saddle-points are evaluated explicitly, and the partition function of ordinary Yang-Mills theory on the sphere is rec

A. Mastichiadis, D. Kazanas

We examine the prompt and afterglow emission within the context of the Supercritical Pile model for GRBs. For this we have performed self-consistent calculations, by solving three time-dependent kinetic equations for protons, electrons and photons in addition to the usual mass and energy conservation equations. We follow the evolution of the RBW as it sweeps

Giorgio Fagiolo, Javier Reyes, Stefano Schiavo

This paper studies the topological properties of the World Trade Web (WTW) and its evolution over time by employing a weighted network analysis. We show that the WTW, viewed as a weighted network, displays statistical features that are very different from those obtained by using a traditional binary-network approach. In particular, we find that: (i) the majo

Dongwon Shin, Zi-Kui Liu

Phase stabilities of Hf-Si-O and Zr-Si-O have been studied with first-principles and thermodynamic modeling. From the obtained thermodynamic descriptions, phase diagrams pertinent to thin film processing were calculated. We found that the relative stability of the metal silicates with respect to their binary oxides plays a critical role in silicide formation

A. -K. Jappsen, S. C. O. Glover, R. S. Klessen, M. -M. Mac Low

In cold dark matter cosmological models, the first stars to form are believed to do so within small protogalaxies. We wish to understand how the evolution of these early protogalaxies changes once the gas forming them has been enriched with small quantities of heavy elements, which are produced and dispersed into the intergalactic medium by the first superno

C. Samanta, D. N. Basu, P. Roy Chowdhury

The $\alpha$-decay half lives of nuclei in the decay from element $^{277}112$ are calculated in a WKB framework using DDM3Y interaction and experimental Q-values. Theoretical estimation of half lives in the same quantum tunneling model, using Q-values from the mass formula of Muntian-Hofmann-Patyk-Sobiczewski, are also presented. Calculated results furnish c

Frank Wilczek

The notion of ``fundamental constant'' is heavily theory-laden. A natural, fairly precise formulation is possible in the context of the standard model (here defined to include gravity). Some fundamental constants have profound geometric meaning. The ordinary gravitational constant parameterizes the stiffness, or resistance to curvature, of space-time. The co

Marc Barthelemy, Alessandro Flammini

Urban streets patterns form planar networks whose empirical properties cannot be accounted for by simple models such as regular grids or Voronoi tesselations. Striking statistical regularities across different cities have been recently empirically found, suggesting that a general and details-independent mechanism may be in action. We propose a simple model b

Olivier Biquard

We prove the unique continuation property at the conformal infinity for asymptotically hyperbolic Einstein metrics.

J. Astrom, P. Di Stefano, F. Proebst, L. Stodolsky

We analyze large sets of energy-release data created by stress-induced brittle fracture in a pure sapphire crystal at close to zero temperature where stochastic fluctuations are minimal. The waiting-time distribution follows that observed for fracture in rock and for earthquakes. Despite strong time correlations of the events and the presence of large-event

R. Dennis Cook, Liqiang Ni

While it is widely accepted that lead-based paint and leaded gasoline are primary sources of elevated concentrations of lead in residential soils, conclusions regarding their relative contributions are mixed and generally study specific. We develop a novel nonlinear regression for soil lead concentrations over time. It is argued that this methodology provide

Peter Fomin, Dmytro Iakubovskyi, Yuri Shtanov

We investigate the possibility of boiling instability of nuclear liquid in the inner core of the proto-neutron star formed in the core collapse of a type II supernova. We derive a simple criterion for boiling to occur. Using this criterion for one of best described equations of state of supernova matter, we find that boiling is quite possible under the condi

A. Pinter, M. Lücke, Ch. Hoffmann

A novel flow state consisting of two oppositely travelling waves (TWs) with oscillating amplitudes has been found in the counterrotating Taylor-Couette system by full numerical simulations. This structure bifurcates out of axially standing waves that are nonlinear superpositions of left and right handed spiral vortex waves with equal time-independent amplitu

Julien M. Hendrickx

Krause's model of opinion dynamics has recently been the object of several studies, partly because it is one of the simplest multi-agent systems involving position-dependent changing topologies. In this model, agents have an opinion represented by a real number and they update it by averaging those agent opinions distant from their opinion by less than a cer

Stavros Garoufalidis

The purpose of the paper is three-fold: (a) we prove that every sequence which is a multidimensional sum of a balanced hypergeometric term has an asymptotic expansion of Gevrey type-1 with rational exponents, (b) we construct a class of $G$-functions that come from enumerative combinatorics, and (c) we give a counterexample to a question of Zeilberger that a

Frank Wilczek

The standard model of fundamental interactions is remarkably successful, but it leaves an unfinished agenda. Several major questions seem ripe for exploration in the near future. I anticipate that the coming decade will be a Golden Age of discovery in fundamental physics.

Joshua D. Bodyfelt, J. A. Mendez-Bermudez, Andrey Chabanov, Tsampikos Kottos

The scaling properties of the inverse moments of Wigner delay times are investigated in finite one-dimensional (1D) random media with one channel attached to the boundary of the sample. We find that they follow a simple scaling law which is independent of the microscopic details of the random potential. Our theoretical considerations are confirmed numericall

Steen Markvorsen, Vicente Palmer

We obtain upper bounds for the isoperimetric quotients of extrinsic balls of submanifolds in ambient spaces which have a lower bound on their radial sectional curvatures. The submanifolds are themselves only assumed to have lower bounds on the radial part of the mean curvature vector field and on the radial part of the intrinsic unit normals at the boundarie

Susanne Pumpluen

We construct Jordan algebras over a locally ringed space using generalizations of the Tits process and the first Tits construction by Achhammer. Some general results on the structure of these algebras are obtained. Examples of Albert algebras over a Brauer-Severi variety with associated central simple algebra of degree 3 are given.

Ciprian Sorin Acatrinei

We consider a simple modification of standard phase-space path integrals and show that it leads in configuration space to Lagrangians depending also on accelerations.

Andrea Bordoni, Nicola Manini

The computation of vibrational spectra of diatomic molecules through the exact diagonalization of algebraically determined matrixes based on powers of Morse coordinates is made substantially more efficient by choosing a properly adapted quantum-mechanical basis, specifically tuned to the molecular potential. A substantial improvement is achieved while still

Michael A. Newton, Fernando A. Quintana, Johan A. den Boon, Srikumar Sengupta

A prespecified set of genes may be enriched, to varying degrees, for genes that have altered expression levels relative to two or more states of a cell. Knowing the enrichment of gene sets defined by functional categories, such as gene ontology (GO) annotations, is valuable for analyzing the biological signals in microarray expression data. A common approach

Alexander Hramov, Alexey Koronovskii

The method of detection of the unstable periodic spatio-temporal states of spatial extended chaotic systems has been proposed. The application of this method is illustrated by the consideration of two different systems: i) the fluid model of Pierce diode being one of the fundamental system of the physics of plasmas and microwave electronics and ii) the compl

S. Drozdz, A. Z. Gorski, J. Kwapien

World currency network constitutes one of the most complex structures that is associated with the contemporary civilization. On a way towards quantifying its characteristics we study the cross correlations in changes of the daily foreign exchange rates within the basket of 60 currencies in the period December 1998 -- May 2005. Such a dynamics turns out to pr