February 2009 arXiv papers — page 41

H. Liu, T. Li, Q. J. Wang, Z. H. Zhu

In this paper, we will propose that magnetic-resonance nanostructures in a metal surface could be used to realize extraordinary optical transmission (EOT). Toward this goal, we designed and fabricated a one dimensional diatomic chain of slit-hole resonator (SHR). Due to the strong exchange current interaction, a type of magnetic plasmon (MP) propagation mode

Wan Kyu Park, Laura H. Greene

We review the current status of Andreev reflection spectroscopy on the heavy fermions, mostly focusing on the case of CeCoIn$_5$, a heavy-fermion superconductor with a critical temperature of 2.3 K. This is a well-established technique to investigate superconducting order parameters via measurements of the differential conductance from nanoscale metallic jun

Marc L. DeRosa, Carolus J. Schrijver, Graham Barnes, K. D. Leka

Nonlinear force-free field (NLFFF) models are thought to be viable tools for investigating the structure, dynamics and evolution of the coronae of solar active regions. In a series of NLFFF modeling studies, we have found that NLFFF models are successful in application to analytic test cases, and relatively successful when applied to numerically constructed

I. Gonzalez Hernandez, P. Scherrer, F. Hill

We show that the mean phase of waves propagating all the way from the far side of the Sun to the front side, as measured by seismic holography, varies with time. The change is highly anticorrelated with solar cycle activity and is consistent with other recent results on the variation of the seismic radius of the Sun. The phase change that we observe correspo

A. T. Deller

(Abridged) This thesis describes the development of DiFX, the first general-purpose software correlator for radio interferometry, and its use with the Australian Long Baseline Array (LBA) to complete the largest VLBI pulsar astrometry program undertaken to date in the Southern Hemisphere. This two year astrometry program has resulted in the measurement of se

D. Anchishkin, A. Muskeyev, S. Yezhov

We propose a mechanism of thermalization of nucleons in relativistic nucleus-nucleus collisions. Our model belongs, to a certain degree, to the transport ones; we consider the evolution of the system, but we parametrize this development by the number of collisions of every particle in the system rather than by the time variable. We based on the assumption th

Patrick McDonald, Arabindo Roy

On very large scales, density fluctuations in the Universe are small, suggesting a perturbative model for large-scale clustering of galaxies (or other dark matter tracers), in which the galaxy density is written as a Taylor series in the local mass density, delta, with the unknown coefficients in the series treated as free "bias" parameters. We exten

A. A. Burkov, Arun Paramekanti

We study the multiband superfluid and the superfluid (SF) to band insulator (BI) transition of strongly interacting fermionic atoms in an optical lattice at a filling of two fermions per well. We present physical arguments to show that a consistent mean field description of this problem is obtained by retaining only intraband pairing between the fermions. Us

Clifford Cheung, Donal O'Connell

The spinor-helicity formalism has become an invaluable tool for understanding the S-matrix of massless particles in four dimensions. In this paper we construct a spinor-helicity formalism in six dimensions, and apply it to derive compact expressions for the three, four and five point tree amplitudes of Yang-Mills theory. Using the KLT relations, it is a stra

R. Bruce Kellogg, Natalia Kopteva

A semilinear singularly perturbed reaction-diffusion equation with Dirichlet boundary conditions is considered in a convex unbounded sector. The singular perturbation parameter is arbitrarily small, and the "reduced equation" may have multiple solutions. A formal asymptotic expansion for a possible solution is constructed that involves boundary and c

E. K. S. Hicks, R. I. Davies, M. A. Malkan, R. Genzel

In a sample of local active galactic nuclei studied at a spatial resolution on the order of 10 pc we show that the interstellar medium traced by the molecular hydrogen v=1-0 S(1) 2.1um line forms a geometrically thick, clumpy disk. The kinematics of the molecular gas reveals general rotation, although an additional significant component of random bulk motion

Rashid M. Djilkibaev, Rostislav V. Konoplich

We present results of a study of the muon decay in orbit (DIO) contribution to the signal region of muon - electron conversion. Electrons from DIO are the dominant source of background for muon - electron conversion experiments because the endpoint of DIO electrons is the same as the energy of electrons from elastic muon - electron conversion. The probabilit

Bogdan A. Dobrescu, Kyoungchul Kong, Rakhi Mahbubani

We show that a top-prime quark as heavy as 600 GeV can be discovered at the Tevatron, provided it is resonantly pair-produced via a vector color octet. If the top-prime originates from a vectorlike quark, then the production of a single top-prime in association with a top may also be observable, even through its decay into a Higgs boson and a top. A color oc

Hock-Seng Goh, Lawrence J. Hall, Piyush Kumar

We propose that the leptonic cosmic ray signals seen by PAMELA and ATIC result from the annihilation or decay of dark matter particles via states of a leptonic Higgs doublet to $τ$ leptons, linking cosmic ray signals of dark matter to LHC signals of the Higgs sector. The states of the leptonic Higgs doublet are lighter than about 200 GeV, yielding large $\ba

Gustav Holzegel

The massive wave equation $\Box_g ψ- α\fracΛ{3} ψ= 0$ is studied on a fixed Kerr-anti de Sitter background $(\mathcal{M},g_{M,a,Λ})$. We first prove that in the Schwarzschild case (a=0), $ψ$ remains uniformly bounded on the black hole exterior provided that $α< {9/4}$, i.e. the Breitenlohner-Freedman bound holds. Our proof is based on vectorfield multipliers

Philippe Brax, Carlos A. Savoy, Arunansu Sil

A model of generalised hybrid inflation in a supersymmetric QCD theory is proposed whose parameters are the gauge coupling and quark masses. Its gravitational coupling to another SQCD sector induces a metastable supersymmetry breaking vacuum of the ISS type as ISS quarks become massive at the end of inflation. Using a known mechanism with a gravitational bre

Sergiu I. Vacaru

A new framework to perturbative quantum gravity is proposed following the geometry of nonholonomic distributions on (pseudo) Riemannian manifolds. There are considered such distributions and adapted connections, also completely defined by a metric structure, when gravitational models with infinite many couplings reduce to two--loop renormalizable effective a

Jasmine N. Millican, Daniel Phelan, Evan L. Thomas, Juscelino B. Leao

A polycrystalline sample of FeSe, which adopts the tetragonal PbO-type structure (P4/nmm) at room temperature, has been prepared using solid state reaction. We have investigated pressure-induced structural changes in tetragonal FeSe at varying hydrostatic pressures up to 0.6 GPa in the orthorhombic (T = 50 K) and tetragonal (T = 190 K) phases using high reso

Ronald Fintushel, Ronald J. Stern, Nathan Sunukjian

We produce infinite families of exotic actions of finite cyclic groups on simply connected smooth 4-manifolds with nontrivial Seiberg-Witten invariants.

Sergiu I. Vacaru

For (2+2)-dimensional nonholonomic distributions, the physical information contained into a spacetime (pseudo) Riemannian metric can be encoded equivalently into new types of geometric structures and linear connections constructed as nonholonomic deformations of the Levi-Civita connection. Such deformations and induced geometric/physical objects are complete

Anvar Mavlyutov

We generalized the construction of deformations of affine toric varieties of K. Altmann and our previous construction of deformations of weak Fano toric varieties to the case of arbitrary toric varieties by introducing the notion of Minkowski sum decompositions of polyhedral complexes. Our construction embeds the original toric variety into a higher dimensio

Dongwoon Bai, Saeed S. Ghassemzadeh, Robert R. Miller, Vahid Tarokh

We consider beam selection using a fixed beamforming network (FBN) at a base station with $M$ array antennas. In our setting, a Butler matrix is deployed at the RF stage to form $M$ beams, and then the best beam is selected for transmission. We provide the proofs of the key properties of the noncentral chi-square distribution and the following properties of

Ian Bruce Burgess, Marco Peccianti, Gaetano Assanto, Roberto Morandotti

We introduce a new form of stable spatio-temporal self-trapped optical packets stemming from the interplay of local and nonlocal nonlinearities. Pulsed self-trapped light beams in media with both electronic and molecular nonlinear responses are addressed to prove that spatial and temporal effects can be decoupled, allowing for independent tuning. We numerica

Gianluca Calcagni, Simone Mercuri

The Barbero-Immirzi (BI) parameter is promoted to a field and a canonical analysis is performed when it is coupled with a Nieh-Yan topological invariant. It is shown that, in the effective theory, the BI field is a canonical pseudoscalar minimally coupled with gravity. This framework is argued to be more natural than the one of the usual Holst action. Potent

Till Bargheer, Niklas Beisert, Florian Loebbert

We present a recursion relation for the explicit construction of integrable spin chain Hamiltonians with long-range interactions. Based on arbitrary short-range (e.g. nearest-neighbor) integrable spin chains, it allows to construct an infinite set of conserved long-range charges. We explain the moduli space of deformation parameters by different classes of g

Yan Qu

The thesis gave a fine study on the distribution of the coefficients of automorphic L-functions for GL(m) with m>1. In particular we have treated two types of problems: change of signs of these coefficients (when they are real) and their decompensation on the prime numbers. Chapter 2 is devoted to the results known concerning the first problem in the case of

T. Valentinuzzi, D. Woods, G. Fasano, M. Riello

Context. This is the third paper of a series devoted to the WIde-field Nearby Galaxy-cluster Survey (WINGS).WINGS is a long term project aimed at gathering wide-field, multiband imaging and spectroscopy of galaxies in a complete sample of 77 X-ray selected nearby clusters (0.04<z<0.07) located far from the galactic plane (b>20deg). The main goal of this proj

C. Bartocci, G. Falqui, I. Mencattini, G. Ortenzi

We show that the bi-Hamiltonian structure of the rational n-particle (attractive) Calogero-Moser system can be obtained by means of a double projection from a very simple Poisson pair on the cotangent bundle of gl(n,R). The relation with the Lax formalism is also discussed.

D. J. Singh, A. S. Sefat, M. A. McGuire, B. C. Sales

We report single crystal synthesis, specific heat and resistivity measurements and electronic structure calculations for BaCr$_2$As$_2$. This material is a metal with itinerant antiferromagnetism, similar to the parent phases of Fe-based high temperature superconductors, but differs in magnetic order. Comparison of bare band structure density of states and t

Edward Witten

ALE and Taub-NUT (or ALF) hyper-Kahler four-manifolds can be naturally constructed as hyper-Kahler quotients. In the ALE case, this construction has long been understood in terms of D-branes; here we give a D-brane derivation in the Taub-NUT case. Likewise, instantons on ALE spaces and on Taub-NUT spaces have ADHM-like constructions related to hyper-Kahler q

Amos Lapidoth, Michele A. Wigger

New achievable rate regions are derived for the two-user additive white Gaussian multiple-access channel with noisy feedback. The regions exhibit the following two properties. Irrespective of the (finite) Gaussian feedback-noise variances, the regions include rate points that lie outside the no-feedback capacity region, and when the feedback-noise variances

Colin Bailey, Joseph Oliveira

In $\mathcal L$, the semilattice of faces of an $n$-cube, we count the number of automorphisms of $\mathcal L$ that fix a given subalgebra -- either pointwise or as a subalgebra. By using Möbius inversion we get a formula for the number of derangements on the $n$-cube in terms of the Möbius function on the lattice of MR-subalgebras. We compute this Möbius fu

Julio C. Rebelo, Bianca Santoro

We consider fibrations of genus 2 over complex surfaces. The purpose of this paper is primarily to provide a geometric description of the possible structures of the fibration on a neighborhood of a singular fiber. In particular it is shown that the &#34;geometric data&#34; of the singular fiber determines the fibration on its neighborhood up to a transversel

Yaryong Heo, Fedor Nazarov, Andreas Seeger

Given a fixed $p\neq 2$, we prove a simple and effective characterization of all radial multipliers of $\cF L^p(\Bbb R^d)$, provided that the dimension $d$ is sufficiently large. The method also yields new $L^q$ space-time regularity results for solutions of the wave equation in high dimensions.

Fabio Costa, Nicholas Harrigan, Terry Rudolph, Caslav Brukner

Quantum experiments usually assume the existence of perfect, classical, reference frames, which allow for the specification of measurement settings (e.g. orientation of the Stern Gerlach magnet in spin measurements) with arbitrary precision. If the reference frames are &#34;bounded&#34; (i.e. quantum systems themselves, having a finite number of degrees of f

S. Rajendran, P. Muruganandam, M. Lakshmanan

We study the interaction of dark-bright solitons in two component Bose-Einstein condensates by suitably tailoring the trap potential, atomic scattering length and atom gain or loss. We show that the coupled Gross-Pitaevskii (GP) equation can be mapped onto the Manakov model. An interesting class of matter wave solitons and their interaction are identified wi

Patricio Gaete, Euro Spallucci

We investigate a recently proposed Higgs-like model (arXiv:0811.4423 [hep-th]), in the framework of a gauge-invariant but path-dependent variables formalism. We compute the static potential between test charges in a condensate of scalars and fermions. In the case of charged massive scalar we recover the screening potential. On the other hand, in the Higgs ca

D. Cerveau, J. Déserti, D. Garba Belko, R. Meziani

The set $\mathscr{F}(2;2)$ of quadratic foliations on the complex projective plane can be identified with a \textsc{Zariski}&#39;s open set of a projective space of dimension 14 on which acts $\mathrm{Aut}(\mathbb{P}^2(\mathbb{C})).$ We classify, up to automorphisms of $\mathbb{P}^2(\mathbb{C}),$ quadratic foliations with only one singularity. There are only

Xue Ping Wang

In this article, we prove the finiteness of the number of eigenvalues for a class of Schrödinger operators $H = -Δ+ V(x)$ with a complex-valued potential $V(x)$ on $\bR^n$, $n \ge 2$. If $\Im V$ is sufficiently small, $\Im V \le 0$ and $\Im V \neq 0$, we show that $N(V) = N(\Re V)+ k$, where $k$ is the multiplicity of the zero resonance of the selfadjoint op

S. I. Bastrukov, H. -K. Chang, I. V. Molodtsova, E. H. Wu

Using the energy variational method of magneto-solid-mechanical theory of a perfectly conducting elastic medium threaded by magnetic field, the frequency spectrum of Lorentz-force-driven global torsional nodeless vibrations of a neutron star with Ferraro&#39;s form of axisymmetric poloidal nonhomogeneous internal and dipole-like external magnetic field is ob

Hristu Culetu

An isotropic expansion for the QGP is proposed in curved Kasner spacetime for an experimental configuration with three dimensional set of beams. The fluid of relativistic particles has no shear viscosity but the nonzero bulk viscosity $ζ$ is time dependent and its value could explain the enormous entropy per baryon of our Universe. In addition, $ζ$ equals th

Michal Horodecki, Jonathan Oppenheim, Andreas Winter

We introduce the concept of mutual independence -- correlations shared between distant parties which are independent of the environment. This notion is more general than the standard idea of a secret key -- it is a fully quantum and more general form of privacy. The states which possess mutual independence also generalize the so called private states -- thos

Lorenz A. Gilch, Sebastian Müller

Directed covers of finite graphs are also known as periodic trees or trees with finitely many cone types. We expand the existing theory of directed covers of finite graphs to those of infinite graphs. While the lower growth rate still equals the branching number, upper and lower growth rates do not longer coincide in general. Furthermore, the behaviour of ra

Jing Jane He, Adam Van Tuyl

The path ideal (of length t >=2) of a graph G is the monomial ideal, denoted I_t(G), whose generators correspond to the directed paths of length t in G. We study some of the algebraic properties of I_t(G) when G is a tree. We first show that I_t(G) is the facet ideal of a simplicial tree. As a consequence, the quotient ring R/I_t(G) is always sequentially Co

David Eriksson, Johan Rathsman, Oscar Stål

This manual describes the public code 2HDMC which can be used to perform calculations in a general, CP-conserving, two-Higgs-doublet model (2HDM). The program features simple conversion between different parametrizations of the 2HDM potential, a flexible Yukawa sector specification with choices of different Z_2-symmetries or more general couplings, a tree-le

Diego Garlaschelli

We introduce the weighted random graph (WRG) model, which represents the weighted counterpart of the Erdos-Renyi random graph and provides fundamental insights into more complicated weighted networks. We find analytically that the WRG is characterized by a geometric weight distribution, a binomial degree distribution and a negative binomial strength distribu

Dimitar Mekerov

We consider an almost complex manifold with Norden metric (i. e. a metric with respect to which the almost complex structure is an anti-isometry). On such a manifold we study a linear connection preserving the almost complex structure and the metric and having a totally skew symmetric torsion tensor (i. e. a 3-form). We prove that if a non-Kaehler almost com

C. Adam, P. Klimas, J. Sanchez-Guillen, A. Wereszczynski

Some models providing shell-shaped static solutions with compact support (compactons) in 3+1 and 4+1 dimensions are introduced, and the corresponding exact solutions are calculated analytically. These solutions turn out to be topological solitons, and may be classified as maps $S^3 \to S^3$ and suspended Hopf maps, respectively. The Lagrangian of these model

Mark F. Flanagan

It is shown that a large class of communication systems which admit a sum-product algorithm (SPA) based receiver also admit a corresponding linear-programming (LP) based receiver. The two receivers have a relationship defined by the local structure of the underlying graphical model, and are inhibited by the same phenomenon, which we call &#39;pseudoconfigura

Huy-Viet Nguyen, Stefano de Gironcoli

Recently there has been a renewed interest in the calculation of exact-exchange and RPA correlation energies for realistic systems. These quantities are main ingredients of the so-called EXX/RPA+ scheme which has been shown to be a promising alternative approach to the standard LDA/GGA DFT for weakly bound systems where LDA and GGA perform poorly. In this pa

M. Ostilli, J. F. F. Mendes

Given a network and a partition in communities, we consider the issues &#34;how communities influence each other&#34; and &#34;when two given communities do communicate&#34;. Specifically, we address these questions in the context of small-world networks, where an arbitrary quenched graph is given and long range connections are randomly added. We prove that,

P. Jaming, M. Matolcsi, P. Móra, F. Szöllősi

We exhibit an infinite family of {\it triplets} of mutually unbiased bases (MUBs) in dimension 6. These triplets involve the Fourier family of Hadamard matrices, $F(a,b)$. However, in the main result of the paper we also prove that for any values of the parameters $(a,b)$, the standard basis and $F(a,b)$ {\it cannot be extended to a MUB-quartet}. The main no

M. Bonomi, D. Branduardi, G. Bussi, C. Camilloni

Here we present a program aimed at free-energy calculations in molecular systems. It consists of a series of routines that can be interfaced with the most popular classical molecular dynamics (MD) codes through a simple patching procedure. This leaves the possibility for the user to exploit many different MD engines depending on the system simulated and on t

Michael Brunnbauer, Bernhard Hanke

For several instances of metric largeness like enlargeability or having hyperspherical universal covers, we construct non-large vector subspaces in the rational homology of finitely generated groups. The functorial properties of this construction imply that the corresponding largeness properties of closed manifolds depend only on the image of their fundament

J. B. Glattfelder, S. Battiston

We present a methodology to extract the backbone of complex networks based on the weight and direction of links, as well as on nontopological properties of nodes. We show how the methodology can be applied in general to networks in which mass or energy is flowing along the links. In particular, the procedure enables us to address important questions in econo

Amir Leshem, Omri Gat

We study the emergence of macrorealism in a harmonic oscillator subject to consecutive measurements of a squeezed action. Since the harmonic oscillator dynamics admits a hidden trajectory formulation, the assumptions of macrorealism are violated only by the measurement process. We demonstrate a breakdown of macrorealism in a wide parameter range that is maxi

Lin Mei, Weimin Yuan, Xiaobo Dong

Active galactic nuclei (AGN) in low surface brightness galaxies (LSBGs) have received little attention in previous studies. In this paper, we present detailed spectral analysis of 194 LSBGs from the Impey et al. (1996) APM LSBG sample which have been observed spectroscopically by the Sloan Digital Sky Survey Data Release 5 (SDSS DR5). Our elaborate spectral

T. Zh. Esirkepov, S. V. Bulanov, M. Kando, A. S. Pirozhkov

An ultra-bright high-intensity X- and gamma-radiation source is proposed. A high-density thin plasma slab, accelerating in the radiation pressure dominant regime by a co-propagating ultra-intense electromagnetic wave, reflects a counter-propagating relativistically strong electromagnetic wave, producing strongly time-compressed and intensified radiation due

C. Bernhard, A. J. Drew, L. Schulz, V. K. Malik

We present a muon spin rotation (\muSR) study of the magnetic and superconducting properties of single crystals of electron-doped BaFe2-xCoxAs2 with x=0.08, 0.20, and 0.25 (Tc=9, 25 and 20K) and of polycrystalline hole-doped Pr1-xSrxFeAsO with x=0 and 0.2 (Tc=15 K). In the former series we observe some interesting parallels with the electron doped SmFeAsO1-x

A. M. Frolov, N. Kiriushcheva, S. V. Kuzmin

The Hamiltonian formulation of the tetrad gravity in any dimension higher than two, using its first order form when tetrads and spin connections are treated as independent variables, is discussed and the complete solution of the three dimensional case is given. For the first time, applying the methods of constrained dynamics, the Hamiltonian and constraints

J. S. Bagla, Girish Kulkarni, T. Padmanabhan

The epoch of reionization and formation of first stars are inter-linked topics that are of considerable interest. We use a simplified approach for studying formation of stars in collapsed haloes, and the resulting ionization of the inter-galactic medium (IGM). We consider a set of LCDM models allowed by observations of CMB temperature and polarization anisot

An-Ping Li

In this paper, we will present an algorithm to resolve the counterfeit coins problem in the case that the number of false coins is unknown in advance.

Zoé Chatzidakis, Ehud Hrushovski

In this paper we introduce a new invariant (the distant degree) for difference field extensions of finite transcendence degree, and we explore some of its properties. We also discuss a generalisation of this invariant and of the limit degree to groups with an automorphism.

Rodrigo G. Pereira, Steven R. White, Ian Affleck

We study the spectral function of interacting one-dimensional fermions for an integrable lattice model away from half-filling. The divergent power-law singularity of the spectral function near the single-particle or single-hole energy is described by an effective x-ray edge type model. At low densities and for momentum near the zone boundary, we find a secon

Syed A. Jafar

We identify the role of equal strength interference links as bottlenecks on the ergodic sum capacity of a $K$ user phase-fading interference network, i.e., an interference network where the fading process is restricted primarily to independent and uniform phase variations while the channel magnitudes are held fixed across time. It is shown that even though t

Tetsuya Ito

For a finite Thurston type ordering < of the braid group B_{n}, we introduce a new normal form of a dual positive braid which we call the C-normal form. This normal form extends Fromentin&#39;s rotating normal form and the author&#39;s C-normal form of positive braids. Using the C-normal form, we give a combinatorial description of the restriction of the ord

Henri Moscovici

We prove a local index formula for a class of twisted spectral triples of type III modeled on the transverse geometry of conformal foliations with locally constant transverse conformal factor. Compared with the earlier proof of the untwisted case, the novel aspect resides in the fact that the twisted analogues of the JLO entire cocycle and of its retraction

Eyal Gruss, Yaron Oz

We consider N=2 supergravity in four dimensions with small R^2 curvature corrections. We construct large charge extremal supersymmetric and non-supersymmetric black hole solutions in all space, and analyze their thermodynamic properties.

Paul Fendley, Matthew P. A. Fisher, Chetan Nayak

We explain how (perturbed) boundary conformal field theory allows us to understand the tunneling of edge quasiparticles in non-Abelian topological states. The coupling between a bulk non-Abelian quasiparticle and the edge is due to resonant tunneling to a zero mode on the quasiparticle, which causes the zero mode to hybridize with the edge. This can be refor

A. T. Deller, M. Bailes, S. J. Tingay

The double pulsar J0737-3039A/B is a unique system with which to test gravitational theories in the strong-field regime. However, the accuracy of such tests will be limited by knowledge of the distance and relative motion of the system. Here we present very long baseline interferometry observations which reveal that the distance to PSR J0737-3039A/B is 1150+

F. Crawford, D. R. Lorimer, B. M. Devour, B. P. Takacs

X-ray pulsations with a 6.85 s period were recently detected in the SMC and were subsequently identified as originating from the Be/X-ray binary system XTE J0103-728. The recent localization of the source of the X-ray emission has made a targeted search for radio pulsations from this source possible. The detection of pulsed radio emission from XTE J0103-728

Luis Gonzalez-Mestres

The implications of AUGER and HiRes results for patterns of Lorentz symmetry violation (LSV) are examined, focusing on weak doubly special relativity (WDSR). If the Greisen-Zatsepin-Kuzmin (GZK) cutoff is definitely confirmed, the mass composition of the highest-energy cosmic-ray spectrum will be a crucial issue to draw precise theoretical consequences from

Colin Bailey, Joseph Oliveira

We show that the variety of symmetric implication algebras is generated from cubic implication algebras and Boolean algebras. We do this by developing the notion of a locally symmetric implication algebra that has properties similar to cubic implication algebras and provide a representation of these algebras as subalgebras of a product of a cubic implication

Sunil Chebolu, Ján Mináč

In this paper we concentrate on the relations between the structure of small Galois groups, arithmetic of fields, Bloch-Kato conjecture, and Galois groups of maximal pro-$p$-quotients of absolute Galois groups.

Elvan Ceyhan

Spatial interaction between two or more classes or species has important implications in various fields and causes multivariate patterns such as segregation or association. Segregation occurs when members of a class or species are more likely to be found near members of the same class or conspecifics; while association occurs when members of a class or speci

Eric W. Greisen, Kristine Spekkens, Gustaaf A. van Moorsel

We present sensitive aperture synthesis observations of the nearby, late-type spiral galaxy NGC 6503, and produce HI maps of considerably higher quality than previous observations by van Moorsel & Wells (1985). We find that the velocity field, while remarkably regular, contains clear evidence for irregularities. The HI is distributed over an area much larger

D. F. Agterberg, Z. Zheng, S. Mukherjee

Reply to Ikeda (arXiv:0712.3341).

Jeffrey H. Shapiro, Seth Lloyd

Lloyd [1] proved that a large performance gain accrues from use of entanglement in single-photon target detection within a lossy, noisy environment when compared to what can be achieved with unentangled single-photon states. We show that the performance of Lloyd&#39;s &#34;quantum illumination&#34; system is, at best, equal to that of a coherent-state transm

G. Ghirlanda, L. Nava, G. Ghisellini, A. Celotti

We compare the spectral properties of 79 short and 79 long Gamma-Ray Bursts (GRBs) detected by BATSE and selected with the same limiting peak flux. Short GRBs have a low-energy spectral component harder and a peak energy slightly higher than long GRBs, but no difference is found when comparing short GRB spectra with those of the first 1-2 sec emission of lon

Soonkeon Nam, Jong-Dae Park

In an insightful approach, Robinson and Wilczek proposed that Hawking radiation can be obtained as the compensation of a breakdown of general covariance and gauge invariance and the radiation is a black body radiation at Hawking temperature. We apply this method to two types of black holes in three dimensional spacetime, which share the general form of the m

P Ao

Quantifying the adaptive landscape in a given dynamical processes has been one of most important goals in theoretical biology. It can have immediate implications for many dynamical properties, such as robustness and plasticity. Based on recent work here I give a nontechnical brief review of this powerful quantitative concept in biology. This concept was init

Amy Lien, Brian D. Fields

Large synoptic (repeated scan) imaging sky surveys are poised to observe enormous numbers of core-collapse supernovae. We quantify the discovery potential of upcoming projects, including DES, Pan-STARRS, and LSST. These surveys will map out the cosmic core-collapse supernova redshift distribution via direct counting, with very small statistical uncertainties

L. Heggland, B. De Pontieu, V. H. Hansteen

We present the results of numerical simulations of wave-induced magnetic reconnection in a model of the solar atmosphere. In the magnetic field geometry we study in this article, the waves, driven by a monochromatic piston and a driver taken from Hinode observations, induce periodic reconnection of the magnetic field, and this reconnection appears to help dr

C. Vignali, F. Fiore, A. Comastri, M. Brusa

Here we review some of the main issues related to multi-wavelength source identification and characterization, with particular emphasis on the field of X-ray surveys carried out over the last years. This complex and time-consuming process is going to represent one of the main difficulties over the coming years, when significantly larger surveys, both in area

S. Nandi, A. Kreyssig, Y. Lee, Yogesh Singh

Element-specific x-ray resonant magnetic scattering investigations were performed to determine the magnetic structure of Eu in EuRh2As2. In the temperature range from 46 K down to 6 K, an incommensurate antiferromagnetic (ICM)structure with a temperature dependent propagation vector (0 0 0.9) coexists with a commensurate antiferromagnetic (CM) structure. Ang

N. T. Huy, A. de Visser

We report the variation of ferromagnetic order in the pseudo-ternary compounds URh_{1-x}Co_{x}Ge (0 \leq x \leq 1). Magnetization and transport data taken on polycrystalline samples show that the Curie temperature T_{C} gradually increases with increasing Co content from a value of 9.5 K for URhGe to a maximum value of 20 K for x = 0.6 and then steadily decr

Miklós Csűrös, István Miklós

A phylogenetic birth-and-death model is a probabilistic graphical model for a so-called phylogenetic profile, i.e., the size distribution for a homolog gene family at the terminal nodes of a phylogeny. Profile datasets are used in bioinformatics analyses for the inference of evolutionary trees, and of functional associations between gene families, as well as

P. Romano, R. P. Mignani, S. Campana, A. Moretti

We present the BMW-Chandra source catalogue derived from Chandra ACIS-I observations (exposure time >10ks) public as of March 2003 by using a wavelet detection algorithm (Lazzati et al. 1999; Campana et al. 1999). The catalogue contains a total of 21325 sources, 16758 of which are serendipitous. Our sky coverage in the soft band (0.5-2 keV, S/N =3) is ~8 deg

Michael J. Harrison

An elementary calculation shows that Landau diamagnetism becomes significantly altered and very large paramagnetic effects emerge at low temperature in nanoscale 2DEG strips penetrated by a perpendicular applied magnetic field and bounded by a parabolic potential, such as may arise from negative voltage applied to a split gate. These novel results are descri

Boris Haspot

This work is devoted to prove existence of global weak solutions for a general isothermal model of capillary fluids derived by J.- E Dunn and J. Serrin (1985) [6], which can be used as a phase transition model. We improve the results of [5] by showing the existence of global weak solution in dimension two for initial data in the energy space, close to a stab

Izabella Laba, Kelan Zhai

Nazarov, Peres and Volberg proved recently that the Favard length of the $n$-th iteration of the four-corner Cantor set is bounded from above by $n^{-c}$ for an appropriate $c$. We generalize this result to all product Cantor sets whose projection in some direction has positive 1-dimensional measure.

R. P. Mignani, F. Kerber, R. L. Smart, D. Vande Putte

Starting from the Strasbourg ESO Catalogue (SEC) of Planetary Nebulae (PNe), the largest PNe compilation available with ~ 1500 objects, we undertook a comprehensive study of the whole PN population, never carried out so far, only using on-line catalogues and data from public imaging surveys. The study includes the PN dynamics through their measured proper mo

Michael E. Wall, David A. Markowitz, Judah L. Rosner, Robert G. Martin

We have developed a mathematical model of transcriptional activation by MarA in Escherichia coli, and used the model to analyze measurements of MarA-dependent activity of the marRAB, sodA, and micF promoters in mar-rob- cells. The model rationalizes an unexpected poor correlation between the mid-point of in vivo promoter activity profiles and in vitro equili

J. -M. Grießmeier, A. Stadelmann, J. L. Grenfell, H. Lammer

Previous studies have shown that extrasolar Earth-like planets in close-in habitable zones around M-stars are weakly protected against galactic cosmic rays (GCRs), leading to a strongly increased particle flux to the top of the planetary atmosphere. Two main effects were held responsible for the weak shielding of such an exoplanet: (a) For a close-in planet,

Robert R. Gibson, W. N. Brandt, S. C. Gallagher, Donald P. Schneider

We examine the UV and X-ray properties of 256 radio-quiet SDSS quasars (QSOs) observed in X-rays with Chandra and/or XMM-Newton in order to study the relationship between QSOs with broad CIV absorption lines (BALs; width >2000 km/s) and those with CIV mini-BALs (here defined to have widths of 1000--2000 km/s). Our sample includes 42 BAL and 48 mini-BAL QSOs.

D. Boyer, O. López-Corona

We introduce a model of traveling agents ({\it e.g.} frugivorous animals) who feed on randomly located vegetation patches and disperse their seeds, thus modifying the spatial distribution of resources in the long term. It is assumed that the survival probability of a seed increases with the distance to the parent patch and decreases with the size of the colo

S. Giraud, R. Combescot

We consider the problem of a single particle interacting with $N$ identical fermions, at zero temperature and in one dimension. We calculate the binding energy as well as the effective mass of the single particle. We use an approximate method developed in the three-dimensional case, where the Hilbert space for the excited states of the $N$ fermions is restri

Ana B. Hungria, Paul A. Midgley, Beatriz H. Juarez, Christian Klinke

The crystallographic structure of CdSe nanoparticles attached to carbon nanotubes has been elucidated by means of high resolution transmission electron microscopy and high angle annular dark field scanning transmission electron microscopy tomography. CdSe rod-like nanoparticles, grown in solution together with carbon nanotubes, undergo a morphological transf

Ethan T. Vishniac

Simulations of the magnetorotational instability (MRI) in a homogeneous shearing box have shown that the asymptotic strength of the magnetic field declines steeply with increasing resolution. Here I model the MRI driven dynamo as a large scale dynamo driven by the vertical magnetic helicity flux. This growth is balanced by large scale mixing driven by a seco

Sandro Azaele, Jayanth R. Banavar, Amos Maritan

We derive exact solutions of simplified models for the temporal evolution of the protein concentration within a cell population arbitrarily far from the stationary state. We show that monitoring the dynamics can assist in modeling and understanding the nature of the noise and its role in gene expression and protein production. We introduce a new measure, the