May 2010 arXiv papers — page 40

K. Sandstrom, O. Krause, H. Linz, E. Schinnerer

Using photometry of NGC 1097 from the Herschel PACS (Photodetector Array Camera and Spectrometer) instrument, we study the resolved properties of thermal dust continuum emission from a circumnuclear starburst ring with a radius ~ 900 pc. These observations are the first to resolve the structure of a circumnuclear ring at wavelengths that probe the peak (i.e.

Antonio De Felice, Jean-Marc Gerard, Teruaki Suyama

In order to classify modified gravity models according to their physical properties, we analyze the cosmological linear perturbations for f(R,G) theories (R being the Ricci scalar and G, the Gauss-Bonnet term) with a minimally coupled perfect fluid. For the scalar type perturbations, we identify in general six degrees of freedom. We find that two of these ph

Boris Pittel

For an ergodic Markov chain $\{X(t)\}$ on $\Bbb N$, with a stationary distribution $π$, let $T_n>0$ denote a hitting time for $[n]^c$, and let $X_n=X(T_n)$. Around 2005 Guy Louchard popularized a conjecture that, for $n\to \infty$, $T_n$ is almost Geometric($p$), $p=π([n]^c)$, $X_n$ is almost stationarily distributed on $[n]^c$, and that $X_n$ and $T_n$ are

Juan Arbiza, Santiago Mirazo, Hugo Fort

Viral quasispecies can be regarded as a swarm of genetically related mutants or a quasispecies (QS). A common formalism to approach QS is the replicator-mutator equation (RME). However, a problem with the RME is how to quantify the interaction coefficients between viral variants. Here, this is addressed by adopting an ecological perspective and resorting to

J. A. Braatz, M. J. Reid, E. M. L. Humphreys, C. Henkel

The Megamaser Cosmology Project (MCP) aims to determine H0 by measuring angular-diameter distances to galaxies in the Hubble flow using observations of water vapor megamasers in the circumnuclear accretion disks of active galaxies. The technique is based only on geometry and determines H0 in one step, independent of standard candles and the extragalactic dis

Aneesh V. Manohar

Reparametrization invariance relations are determined for the inclusive decay spectra of heavy hadrons. They connect the leading order result to the lambda_1 term, and the lambda_2 and rho_2 terms, and imply that the lambda_1 and rho_2 terms in the total rate occur in the combinations 1+lambda_1/(2m_Q^2) and lambda_2-rho_2/m_Q. The relations are satisfied by

Boris Pittel, Ji-A Yeum

We consider a random system of equations $x_i+x_j=b_{(i,j)} (\text{mod }2)$, $(x_u\in \{0,1\},\, b_{(u,v)}=b_{(v,u)}\in\{0,1\})$, with the pairs $(i,j)$ from $E$, a symmetric subset of $[n]\times [n]$. $E$ is chosen uniformly at random among all such subsets of a given cardinality $m$; alternatively $(i,j)\in E$ with a given probability $p$, independently of

Y. Boughaleb, M. Noureddine, R. Nassif

When interfaces between ordered domains are ordered clusters, frustration disappears. A phase with mixed ordered structures emerges but no length scale can be associated to. We show that sum of densities of each structure plays the role of order parameter. For, we consider a regular half full lattice with repulsive interaction extended to second neighboring

Drew Armstrong

In 2003, Haglund's {\sf bounce} statistic gave the first combinatorial interpretation of the $q,t$-Catalan numbers and the Hilbert series of diagonal harmonics. In this paper we propose a new combinatorial interpretation in terms of the affine Weyl group of type $A$. In particular, we define two statistics on affine permutations; one in terms of the Shi

G. W. Ford, Yang Gao, R. F. O'Connell

Entanglement, which is an essential characteristic of quantum mechanics, is the key element in potential practical quantum information and quantum communication systems. However, there are many open and fundamental questions (relating to entanglement measures, sudden death, etc.) that require a deeper understanding. Thus, we are motivated to investigate a si

A. Stutz, R. Launhardt, H. Linz, O. Krause

We present Herschel observations of the isolated, low-mass star-forming Bok globule CB244. It contains two cold sources, a low-mass Class 0 protostar and a starless core, which is likely to be prestellar in nature, separated by 90 arcsec (~ 18000 AU). The Herschel data sample the peak of the Planck spectrum for these sources, and are therefore ideal for dust

D. Cormier, S. C. Madden, S. Hony, A. Contursi

We present Herschel/PACS spectroscopic maps of the dwarf galaxy NC4214 observed in 6 far infrared fine-structure lines: [C II] 158mu, [O III] 88mu, [O I] 63mu, [O I] 146mu, [N II] 122mu, and [N II] 205mu. The maps are sampled to the full telescope spatial resolution and reveal unprecedented detail on ~ 150 pc size scales. We detect [C II] emission over the w

B. Ashok, T. K. Patra

We discuss how phase-transitions may be detected in computationally hard problems in the context of Anytime Algorithms. Treating the computational time, value and utility functions involved in the search results in analogy with quantities in statistical physics, we indicate how the onset of a computationally hard regime can be detected and the transit to hig

Jan Forbrich, Achim Tappe, Thomas Robitaille, August A. Muench

When studying the evolutionary stages of protostars that form in clusters, the role of any intracluster medium cannot be neglected. High foreground extinction can lead to situations where young stellar objects (YSOs) appear to be in earlier evolutionary stages than they actually are, particularly when using simple criteria like spectral indices. To address t

Thomas Henning, Hendrik Linz, Oliver Krause, Sarah Ragan

Infrared-dark clouds (IRDCs) are the precursors to massive stars and stellar clusters. G011.11-0.12 is a well-studied filamentary IRDC, though, to date, the absence of far-infrared data with sufficient spatial resolution has limited the understanding of the structure and star-formation activity. We use Herschel to study the embedded population of young pre-

Shamayita Ray

We consider different extensions of the standard model which can give rise to the small active neutrino masses through seesaw mechanisms, and their mixing. These tiny neutrino masses are generated at some high energy scale by the heavy seesaw fields which then get sequentially decoupled to give an effective dimension-5 operator. The renormalization group evo

H. Linz, O. Krause, H. Beuther, Th. Henning

The intermediate-mass star-forming core UYSO 1 has previously been found to exhibit intriguing features. While deeply embedded and previously only identified by means of its (sub-)millimeter emission, it drives two powerful, dynamically young, molecular outflows. Although the process of star formation has obviously started, the chemical composition is still

J. L. Dunn, C. Stahl, Y. Reshitnyk, W. Sim

Theoretical and experimental work have not provided a consistent picture of the phase diagram of the nearly ideal Ising ferromagnet LiHoF4 in a transverse magnetic field. Using a newly fabricated capacitive dilatometer, we have investigated the thermal expansion and magnetostriction of LiHoF4 in magnetic fields applied perpendicular to the Ising direction. C

Michael Wick, Andrew McCallum, Gerome Miklau

Probabilistic databases play a crucial role in the management and understanding of uncertain data. However, incorporating probabilities into the semantics of incomplete databases has posed many challenges, forcing systems to sacrifice modeling power, scalability, or restrict the class of relational algebra formula under which they are closed. We propose an a

Joel N. Bregman, Michael E. Anderson, Xinyu Dai

The metallicity in galaxy clusters is expected to originate from the stars in galaxies, with a population dominated by high mass stars likely being the most important stellar component, especially in rich clusters. We examine the relationship between the metallicity and the prominence of galaxies as measured by the star to baryon ratio, M$_*$/M$_{bary}$. Cou

Michael L. Brown, Richard A. Battye

We propose a new technique for weak gravitational lensing in the radio band making use of polarization information. Since the orientation of a galaxy's polarized emission is both unaffected by lensing and is related to the galaxy's intrinsic orientation, it effectively provides information on the unlensed galaxy position angle. We derive a new weak l

Marta M. Cassiano, Pierre Kaufmann, Rogerio Marcon, Amauri S. Kudaka

Solar observations in the mid-infrared 8-14 μ\m band continuum were carried out with cadence of 5 frames per second, in December 2007. Rapid small heated sources, with typical duration of the order of seconds, were found on the bright plage-like areas around sunspots, in association with relatively weak GOES soft X-ray bursts. This work presents the analysis

Kenneth Maussang, G. Edward Marti, Tobias Schneider, Philipp Treutlein

We measure atom number statistics after splitting a gas of ultracold 87Rb atoms in a purely magnetic double-well potential created on an atom chip. Well below the critical temperature for Bose-Einstein condensation T_c, we observe reduced fluctuations down to -4.9dB below the atom shot noise level. Fluctuations rise to more than +3.8dB close to T_c, before r

Karin Baur, Lutz Hille

Let $\Aa_t$ be the directed quiver of type $\Aa$ with $t$ vertices. For each dimension vector $d$ there is a dense orbit in the corresponding representation space. The principal aim of this note is to use just rank conditions to define the irreducible components in the complement of the dense orbit. Then we compare this result with already existing ones by K

Archil Gulisashvili, Josep Vives

We consider uncorrelated Stein-Stein, Heston, and Hull-White models and their perturbations by compound Poisson processes with jump amplitudes distributed according to a double exponential law. Similar perturbations of the Black-Scholes model were studied by S. Kou. For perturbed stochastic volatility models, we obtain two-sided estimates for the stock price

D. A. Naylor, E. Dartois, E. Habart, A. Abergel

Aims. To follow the species chemistry arising in diverse sources of the Galaxy with Herschel. Methods. SPIRE FTS sparse sampled maps of the Orion bar & compact HII regions G29.96-0.02 and G32.80+0.19 have been analyzed. Results. Beyond the wealth of atomic and molecular lines detected in the high-resolution spectra obtained with the FTS of SPIRE in the Orion

Mark S. Grinshpon, Peter A. Linnell, Michael J. Puls

Let G be an infinite discrete group of type FP-infinity and let p>1 be a real number. We prove that the l^p-homology and cohomology groups of G are either 0 or infinite dimensional. We also show that the cardinality of the p-harmonic boundary of a finitely generated group is either 0, 1, or infinity.

Charles Bonatto, Eduardo Bica

We derive fundamental, structural, and photometric parameters of 15 overlooked Ruprecht (hereafter Ru) star clusters by means of 2MASS photometry and field-star decontamination. Ru\,1, 10, 23, 26, 27, 34, 35, 37, 41, 54, 60, 63, 66, and 152 are located in the third Galactic quadrant, while Ru\,174 is in the first. With the constraints imposed by the field-de

A. Semenov

We present a new version 3.1 of the LanHEP software package. New features of the program include tools for the models with extra dimensions, implementation of the particle classes for FeynArts output and using templates with LanHEP statements.

Michael I. Buchoff

Effective field theories provide a formalism for categorizing low-energy effects of a high-energy fundamental theory in terms of the low-energy degrees of freedom. This process has been well established in mapping the fundamental theory of QCD in terms of the hadronic degrees of freedom, which allows for quantitative connections and predictions between hardr

David Aristoff, Charles Radin

We introduce a model of granular matter and use a stress ensemble to analyze shearing. Monte Carlo simulation shows the model to exhibit a second order phase transition, associated with the onset of dilatancy.

A. Cetoli, E. Lundh

We investigate the behavior of a two dimensional array of Bose-Einstein condensate tubes described by means of a Bose-Hubbard Hamiltonian. Using a Wannier function expansion for the wavefunction in each tube, we compute the Bose-Hubbard parameters related to two different longitudinal potentials, periodic and quasiperiodic. We predict that - upon increasing

Jo Stanley, Gerard Briscoe

The European Commission has the power to inspire, initiate and sponsor huge transnational projects to an extent impossible for most other entities. These projects can address universal themes and develop well-being models that are valuable across a diversity of societies and economies. It is a universal fact that SMEs in all countries provide a substantial p

L. V. E. Koopmans

A tomographic method is described to quantify the three-dimensional power-spectrum of the ionospheric electron-density fluctuations based on radio-interferometric observations by a two-dimensional planar array. The method is valid to first-order Born approximation and might be applicable to correct observed visibilities for phase variations due to the imprin

Georgios Roumpos, Michael D. Fraser, Andreas Löffler, Sven Höfling

In a homogeneous two-dimensional system at non-zero temperature, although there can be no ordering of infinite range, a superfluid phase is predicted for a Bose liquid. The stabilization of phase in this superfluid regime is achieved by the formation of bound vortex-antivortex pairs. It is believed that several different systems share this common behaviour,

A. Doff, A. A. Natale

There are quasi-conformal theories, like the Minimal and Ultraminimal Technicolor models, which may break dynamically the gauge symmetry of the Standard Model and at the same time are compatible with electroweak precision data. The main characteristic of this type of models is their fermionic content in one or more higher dimensional representations, therefo

Terence J Tarnowsky

Enhanced fluctuations and correlations have been observed in the phase transitions of many systems. Their appearance at the predicted QCD phase transition (especially near the expected critical point) may provide insight into the nature of the phase transition. Recent results from the STAR experiment will be presented with a focus on particle ratio (K/$π$ an

Carmeliza Navasca, Michael Opperman, Timothy Penderghest, Christino Tamon

Braman [B08] described a construction where third-order tensors are exactly the set of linear transformations acting on the set of matrices with vectors as scalars. This extends the familiar notion that matrices form the set of all linear transformations over vectors with real-valued scalars. This result is based upon a circulant-based tensor multiplication

Annibale D'Ercole, Francesca D'Antona, Paolo Ventura, Enrico Vesperini

A large number of spectroscopic studies have provided evidence of the presence of multiple populations in globular clusters by revealing patterns in the stellar chemical abundances. This paper is aimed at studying the origin of these abundance patterns. We explore a model in which second generation (SG) stars form out of a mix of pristine gas and ejecta of t

G. J. Bendo, C. D. Wilson, M. Pohlen, M. Sauvage

We use Herschel Space Observatory data to place observational constraints on the peak and Rayleigh-Jeans slope of dust emission observed at 70-500 microns in the nearby spiral galaxy M81. We find that the ratios of wave bands between 160 and 500 microns are primarily dependent on radius but that the ratio of 70 to 160 micron emission shows no clear dependenc

V. A. Rubakov

We point out that there is a difference between the behavior of fermionic systems (and their holographic analogs) in a background axial vector field, on the one hand, and at finite chiral chemical potential, on the other. In the former case, the electric current induced by constant background axial field $A_0$ and magnetic field ${\bf B}$ vanishes, while in

C. W. Engelbracht, L. K. Hunt, R. A. Skibba, J. L. Hinz

Stellar density and bar strength should affect the temperatures of the cool (T ~ 20-30 K) dust component in the inner regions of galaxies, which implies that the ratio of temperatures in the circumnuclear regions to the disk should depend on Hubble type. We investigate the differences between cool dust temperatures in the central 3 kpc and disk of 13 nearby

Alberto Accomazzi, Michael J. Kurtz, Stephen S. Murray

Over the past decade, astronomers have been using an increasingly larger number of web-based applications and archives to conduct their research. However, despite the early success in creating links across projects and data centers, the promise of a single integrated digital library environment supporting e-science in astronomy has proven elusive. While some

H. M. Günther, N. Lewandowska, M. P. G. Hundertmark, H. Steinle

Classical T Tauri stars (CTTS) are young, late-type objects, that still accrete matter from a circumstellar disk. Analytical treatments and numerical simulations predict instabilities of the accretion shock on the stellar surface. We search for variability on timescales below a few minutes in the CTTS TW Hya and AA Tau. TW Hya was observed with SALTICAM on t

Emmanuel Breuillard, Ben Green, Terence Tao

We establish various results on the structure of approximate subgroups in linear groups such as SL_n(k) that were previously announced by the authors. For example, generalising a result of Helfgott (who handled the cases n = 2 and 3), we show that any approximate subgroup of SL_n(F_q) which generates the group must be either very small or else nearly all of

K. Byczuk, D. Vollhardt

In their preprint Anders et al. [arXiv:1004.0510] propose a crucial modification of the Bosonic Dynamical Mean-Field Theory (B-DMFT) derived by us [Phys. Rev. B 77, 235106 (2008)]. Here we show that the modification consists of two steps which, in fact, cancel each other. Consequently their self-consistency equations are identical to ours.

Brendan Hassett, Anthony Várilly-Alvarado, Patrick Varilly

We construct an explicit K3 surface over the field of rational numbers that has geometric Picard rank one, and for which there is a transcendental Brauer-Manin obstruction to weak approximation. To do so, we exploit the relationship between polarized K3 surfaces endowed with particular kinds of Brauer classes and cubic fourfolds.

F. Cannata, A. Yu. Kamenshchik

An exact solution describing the evolution of the type Bang-to-Rip with the phantom divide line crossing is constructed in the Chameleon cosmology model, based on two independent functions of the scalar field.

P. Panuzzo, N. Rangwala, A. Rykala, K. G. Isaak

We present the observations of the starburst galaxy M82 taken with the Herschel SPIRE Fourier Transform Spectrometer. The spectrum (194-671 μm) shows a prominent CO rotational ladder from J = 4-3 to 13-12 emitted by the central region of M82. The fundamental properties of the gas are well constrained by the high J lines observed for the first time. Radiative

J. Mao

Long-duration gamma-ray bursts(LGRBs) are believed to be linked with the star formation. We adopt a galactic evolution model, in which the star formation process inside the virialized dark halo at given redshift can be achieved. In this paper, the gamma-ray burst(GRB) host galaxies are assumed to be the star-forming galaxies within the small dark halos. The

Jan Staff, Rachid Ouyed

In this paper we consider a quark nova occurring inside an exploding star. The quark nova ejecta will shock when interacting with the stellar envelope. When this shock reaches the surface of the star, the energy is radiated away. We suggest that this energy may be seen in X-rays, and show here that this may explain some flares seen in the X-ray afterglow of

Martin Eckstein, Philipp Werner

We solve the impurity problem which arises within nonequilibrium dynamical mean-field theory for the Hubbard model by means of a self-consistent perturbation expansion around the atomic limit. While the lowest order, known as the non-crossing approximation (NCA), is reliable only when the interaction U is much larger than the bandwidth, low-order corrections

C. Ragone-Figueroa, M. Plionis, M. Merchan, S. Gottlober

We use dark matter haloes identified in the MareNostrum Universe and galaxy groups identified in the Sloan Data Release 7 galaxy catalogue, to study the relation between halo shape and halo dynamics, parametrizing out the mass of the systems. A strong shape-dynamics, independent of mass, correlation is present in the simulation data, which we find it to be d

Z. Elekes, Zs. Vajta, Zs. Dombradi, T. Aiba

The structure of neutron rich nitrogen nuclei has been studied by use of neutron removal reaction and inelastic scattering. Mass and charge deformations have been deduced for the first excited state of 21N, which indicates the partial persitence of the N=14 subshell closure in nitrogen isotopes. The spectroscopic information obtained on the structure of 19,2

Aleksandar Mikovic, Marko Vojinovic

We analyze the large-spin asymptotics of a class of spin-network wavefunctions of Euclidean Loop Quantum Gravity, which corresponds to a flat spacetime. A wavefunction from this class can be represented as a sum over the spins of an amplitude for a spin network whose graph is a composition of the the wavefunction spin network graph with the dual one-complex

S. Hony, F. Galliano, S. C. Madden, P. Panuzzo

We study the structure of the medium surrounding sites of high-mass star formation to determine the interrelation between the HII regions and the environment from which they were formed. The density distribution of the surroundings is key in determining how the radiation of the newly formed stars interacts with the surrounds in a way that allows it to be use

Na-na Pan, Xiao-ping Zheng

The authors try to probe the inner components of rapidly rotating compact stars such as the millisecond pulsar SAX J1808.4-3658 and the possible sub-millisecond pulsar XTE J1739-285 in their own way by comparing the genuine rotation frequencies under different theoretical models with the observational data, which may exert more stringent constraint on matter

Yair Goldberg, Ya'acov Ritov, Avishai Mandelbaum

We show how to construct the best linear unbiased predictor (BLUP) for the continuation of a curve in a spline-function model. We assume that the entire curve is drawn from some smooth random process and that the curve is given up to some cut point. We demonstrate how to compute the BLUP efficiently. Confidence bands for the BLUP are discussed. Finally, we a

Aleksandar Mijatović, Mikhail Urusov

We obtain a deterministic characterisation of the \emph{no free lunch with vanishing risk}, the \emph{no generalised arbitrage} and the \emph{no relative arbitrage} conditions in the one-dimensional diffusion setting and examine how these notions of no-arbitrage relate to each other.

Xiang-Dong Li

The author presented the results on the evolution of NS LMXBs and the formation of UCXBs(Ma & Li 2009 for details), and proposed a scenario for the formation of UCXBs from L/IMXBs with the aid of a CB disk in this work.

Stefan Weinzierl

In these lectures I will give an introduction to Feynman integrals. In the first part of the course I review the basics of the perturbative expansion in quantum field theories. In the second part of the course I will discuss more advanced topics: Mathematical aspects of loop integrals related to periods, shuffle algebras and multiple polylogarithms are cover

F. Martins, J. -F. Donati, W. L. F. Marcolino, J. -C. Bouret

We report the detection of a magnetic field on the Of?p star HD108. Spectropolarimetric observations conducted in 2007, 2008 and 2009 respectively with NARVAL@TBL and ESPaDOnS@CFHT reveal a clear Zeeman signature in the average Stokes V profile, stable on timescales of days to months and slowly increasing in amplitude on timescales of years. We speculate tha

Peter Olsson

A model of soft frictionless disks in two dimensions at zero temperature is simulated with a shearing dynamics to study various kinds of asymmetries in sheared systems. We examine both single particle properties, the spatial velocity correlation function, and a correlation function designed to separate clockwise and counter-clockwise rotational fields from o

Jakob Wachsmuth, Stefan Teufel

We derive the effective Hamiltonian for a quantum system constrained to a submanifold (the constraint manifold) of configuration space (the ambient space) in the asymptotic limit where the restoring forces tend to infinity. In contrast to earlier works we consider at the same time the effects of variations in the constraining potential and the effects of int

M. Sauvage, N. Sacchi, G. J. Bendo, A. Boselli

With appropriate spatial resolution, images of spiral galaxies in thermal infrared (~10 micron and beyond) often reveal a bright central component, distinct from the stellar bulge, superimposed on a disk with prominent spiral arms. ISO and Spitzer studies have shown that much of the scatter in the mid-infrared colors of spiral galaxies is related to changes

H. M. Cuppen, L. E. Kristensen, E. Gavardi

H2 formation is an important process in post-shock regions, since H2 is an active participant in the cooling and shielding of the environment. The onset of H2 formation therefore has a strong effect on the temperature and chemical evolution in the post shock regions. We recently developed a model for H2 formation on a graphite surface in warm conditions. The

J. M. Kirk, E. Polehampton, L. D. Anderson, J. -P. Baluteau

We use the SPIRE Fourier-Transform Spectrometer (FTS) on-board the ESA Herschel Space Telescope to analyse the submillimetre spectrum of the Ultra-compact HII region G29.96-0.02. Spectral lines from species including 13CO, CO, [CI], and [NII] are detected. A sparse map of the [NII] emission shows at least one other HII region neighbouring the clump containin

Men-Quan Liu, Ye-Fei Yuan

Based on the steady state equilibrium condition for neutron-proton-electron-positron gas in the neutrino-driven wind from protoneutron star, we estimate the initial electron fraction in the wind in a simple and effective way. We find that the condition in the wind might be propriate for the r-process nucleosynthesis.

Y. I. Izotov, N. G. Guseva, K. J. Fricke, G. Stasinska

Active galactic nuclei (AGNs) have typically been discovered in massive galaxies of high metallicity. We attempt to increase the number of AGN candidates in low metallicity galaxies. We present VLT/UVES and archival VLT/FORS1 spectroscopic and NTT/SUSI2 photometric observations of the low-metallicity emission-line galaxy Tol 2240-384 and perform a detailed s

Matheus P. Viana, Luciano da F. Costa

Since its recent introduction, the small-world effect has been identified in several important real-world systems. Frequently, it is a consequence of the existence of a few long-range connections, which dominate the original regular structure of the systems and implies each node to become accessible from other nodes after a small number of steps, typically o

Jordi Marzo, Kristian Seip

The norm of the Riesz projection from $L^\infty(\T^n)$ to $L^p(\T^n)$ is considered. It is shown that for $n=1$, the norm equals $1$ if and only if $p\le 4$ and that the norm behaves asymptotically as $p/(πe)$ when $p\to \infty$. The critical exponent $p_n$ is the supremum of those $p$ for which the norm equals $1$. It is proved that $2+2/(2^n-1)\le p_n <4$

Rumpa Choudhury, Bhaswati Mookerjea, H. C. Bhatt

We have investigated the young stellar population in and around SFO 38, one of the massive globules located in the northern part of the Galactic HII region IC 1396, using the Spitzer IRAC and MIPS observations (3.6 to 24 micron) and followed up with ground based optical photometric and spectroscopic observations. Based on the IRAC and MIPS colors and H-alpha

Sante Carloni, Rituparno Goswami, Peter K. S. Dunsby

We present a new approach of the reconstruction method based on the use of the cosmic parameters instead of a time law for the scale factor. This allows the derivation and analysis of a set of new non-trivial cosmological solutions for $f(R)$-gravity. A number of simple examples are given.

Peter Buser, John Conway, Peter Doyle, Klaus-Dieter Semmler

We give a number of examples of isospectral pairs of plane domains, and a particularly simple method of proving isospectrality. One of our examples is a pair of domains that are not only isospectral but homophonic: Each domain has a distinguished point such that corresponding normalized Dirichlet eigenfunctions take equal values at the distinguished points.

U. Becciani, A. Costa, V. Antonuccio-Delogu, G. Caniglia

VisIVO is an integrated suite of tools and services specifically designed for the Virtual Observatory. This suite constitutes a software framework for effective visual discovery in currently available (and next-generation) very large-scale astrophysical datasets. VisIVO consists of VisiVO Desktop - a stand alone application for interactive visualization on s

Magali Florens, Bernard Sapoval, Marcel Filoche

Most of the studies on optimal transport are done for steady state regime conditions. Yet, there exists numerous examples in living systems where supply tree networks have to deliver products in a limited time due to the pulsatile character of the flow. This is the case for mammals respiration for which air has to reach the gas exchange units before the star

Benjamin Steinberg

We prove the Cerny conjecture for one-cluster automata with prime length cycle. Consequences are given for the hybrid Road-coloring-Cerny conjecture for digraphs with a proper cycle of prime length.

J. A. Digby-North, K. Nandra, E. S. Laird, C. C. Steidel

We present the results of spectroscopic, narrow-band and X-ray observations of a z=2.30 protocluster in the field of the QSO HS 1700+643. Using a sample of BX/MD galaxies, which are selected to be at z~2.2-2.7 by their rest-frame ultraviolet colours, we find that there are 5 protocluster AGN which have been identified by characteristic emission-lines in thei

Shannon Bishop

Fourier integral operators with sufficiently smooth phase act on the time-frequency content of functions. However time-frequency analysis has only recently been used to analyze these operators. In this paper, we show that if a Fourier integral operator has a smooth phase function and its symbol is well-localized in time and frequency, then the operator is Sc

N. Bucciantini, J. Arons, E. Amato

We present a new model for the spectral evolution of Pulsar Wind Nebulae inside Supernova Remnants. The model couples the long-term dynamics of these systems, as derived in the 1-D approximation, with a 1-zone description of the spectral evolution of the emitting plasma. Our goal is to provide a simplified theoretical description that can be used as a tool t

Ajanta Kundu, Sandip Sarkar

We demonstrate the ability of centre surround model for simulating the enhancement of contrast sensitivity through stochastic resonance observed in psychophysical experiments. We also show that this model could be used to simulate the contrast sensitivity function through stochastic resonance. The quality of the fit of measured contrast sensitivity function

E. F. Sheka, B. S. Razbirin, E. A. Nikitina D. K. Nelson

Conventionally, the Ih symmetry of fullerene C60 is accepted which is supported by numerous calculations. However, this conclusion results from the consideration of the molecule electron system, of its odd electrons in particular, in a close-shell approximation without taking the electron spin into account. Passing to the open-shell approximation has lead to

Z. Z. Sun, Alexander Lopez, John Schliemann

Nanomagnetism has recently attracted explosive attention, in particular, because of the enormous potential applications in information industry, e.g. new harddisk technology, race-track memory[1], and logic devices[2]. Recent technological advances[3] allow for the fabrication of single-domain magnetic nanoparticles (Stoner particles), whose magnetization dy

Clément Barraud, Pierre Seneor, Richard Mattana, Stéphane Fusil

Whereas spintronics brings the spin degree of freedom to electronic devices, molecular/organic electronics adds the opportunity to play with the chemical versatility. Here we show how, as a contender to commonly used inorganic materials, organic/molecular based spintronics devices can exhibit very large magnetoresistance and lead to tailored spin polarizatio

Guinevere Kauffmann, Cheng Li, Timothy M. Heckman

We have compiled a large sample of isolated central galaxies from the Sloan Digital Sky Survey, which do not have a neighbour of comparable brightness within a projected distance of 1 Mpc. We use the colours, luminosities and surface brightnesses of satellite galaxies in the vicinity of these objects to estimate their atomic gas content and to derive the ave

S. V. Syzranov, I. L. Aleiner, B. L. Altshuler, K. B. Efetov

The superconductor-insulator transition (SIT) in regular arrays of Josephson junctions is studied at low temperatures. Near the transition a Ginzburg-Landau type action containing the imaginary time is derived. The new feature of this action is that it contains a gauge field $Φ$ describing the Coulomb interaction and changing the standard critical behavior.

Ivo Sachs, Andreas Wipf

The temperature dependence of the order parameter of the Schwinger model is calculated in the euclidean functional integral approach. For that we solve the model on a finite torus and let the spatial extension tend to infinity at the end of the computations. The induced actions, fermionic zero-modes, relevant Green functions and Wilson loop correlators on th

Alessandro Calamai, Massimo Furi, Alfonso Vignoli

Given any continuous self-map f of a Banach space E over K (where K is R or C) and given any point p of E, we define a subset sigma(f,p) of K, called spectrum of f at p, which coincides with the usual spectrum sigma(f) of f in the linear case. More generally, we show that sigma(f,p) is always closed and, when f is C^1, coincides with the spectrum sigma(f&#39

G. Katsaros, P. Spathis, M. Stoffel, F. Fournel

The epitaxial growth of germanium on silicon leads to the self-assembly of SiGe nanocrystals via a process that allows the size, composition and position of the nanocrystals to be controlled. This level of control, combined with an inherent compatibility with silicon technology, could prove useful in nanoelectronic applications. Here we report the confinemen

Takahisa Igata, Tatsuhiko Koike, Hideki Ishihara

We discuss constants of motion of a particle under an external field in a curved spacetime, taking into account the Hamiltonian constraint which arises from reparametrization invariance of the particle orbit. As the necessary and sufficient condition for the existence of a constant of motion, we obtain a set of equations with a hierarchical structure, which

Ilkka Kylänpää, Tapio T. Rantala

Full quantum statistical $NVT$ simulation of the five-particle system H$_3^+$ has been carried out using the path integral Monte Carlo method. Structure and energetics is evaluated as a function of temperature up to the thermal dissociation limit. The weakly density dependent dissociation temperature is found to be around $4000$ K. Contributions from the qua

M Baldo, LM Robledo, P. Schuck, X. Viñas

In recent years impressive progress has been made in the development of highly accurate energy density functionals, which allow to treat medium-heavy nuclei. In this approach one tries to describe not only the ground state but also the first relevant excited states. In general, higher accuracy requires a larger set of parameters, which must be carefully chos

M. G. Poghosyan

We study UA5 published data on $p\bar{p}$ interaction cross-sections and on charged particles pseudorapidity distribution in single-diffractive, non-single diffractive and inelastic events and investigate their consistency/inconsistency.

Xavier Calmet

The aim of this article is to review the recent developments in the phenomenology of quantum gravity at the Large Hadron Collider. We shall pay special attention to four-dimensional models which are able to lower the reduced Planck mass to the TeV region and compare them to models with a large extra-dimensional volume. We then turn our attention to reviewing

Yipeng Liu, Qun Wan

Too high sampling rate is the bottleneck to wideband spectrum sensing for cognitive radio (CR). As the survey shows that the sensed signal has a sparse representation in frequency domain in the mass, compressed sensing (CS) can be used to transfer the sampling burden to the digital signal processor. An analog to information converter (AIC) can randomly sampl

Yipeng Liu, Qun Wan, Xiaoli Chu

This paper presents a power-efficient mask-constrained ultra-wideband (UWB) waveform design with radio channel effects taken into consideration. Based on a finite impulse response (FIR) filter, we develop a convex optimization model with respect to the autocorrelation of the filter coefficients to optimize the transmitted signal power spectrum, subject to a

Pawel Romanczuk, Felix Mueller, Lutz Schimansky-Geier

We consider overdamped Brownian dynamics in a periodic potential with temporally oscillating amplitude. We analyze the transport which shows effective diffusion enhanced by the oscillations and derive approximate expressions for the diffusion coefficient. Furthermore we analyze the effect of the oscillating potential on the transport if additionally a consta

Emmanuel Lhuillier, Emmanuel Rosencher, Isabelle Ribet-Mohamed, Alexandru Nedelcu

Dark current is shown to be significantly reduced in quantum well infrared photodetectors in the tunneling regime, i.e. at very low temperature, by shifting the dopant impurity layers away from the central part of the wells. This result confirms that the interwell tunneling current is dominated by charged impurity scattering in usual structures. The experime

H. S. Nataraj, B. K. Sahoo, B. P. Das, D. Mukherjee

The electric dipole moment (EDM) enhancement factor of atomic Tl is of considerable interest as it has been used in determining the most accurate intrinsic electron EDM limit to date. However, the value of this quantity varies from $-179$ to $-1041$ in different approximations. In view of the large uncertainties associated with many of these calculations, we

L. Prechtel, S. Manus, D. Schuh, W. Wegscheider

We apply a pump- and probe-scheme to coplanar stripline circuits to investigate the photocurrent response of GaAs photoswitches in time and space. We find a displacement current pulse, as has been reported earlier. A time-delayed second pulse is interpreted by a transport current. A time-of-flight analysis allows us to determine the velocity of the photogene