arXiv papers from February 2008

J. L. Christiansen, E. Albin, K. A. James, J. Goldman

We search Hubble Space Telescope Treasury Program images collected as part of the Great Observatories Origins Deep Survey for pairs of galaxies consistent with the gravitational lensing signature of a cosmic string. Our technique includes estimates of the efficiency for finding the lensed galaxy pair. In the north (south) survey field we find no evidence out

D0 Collaboration, V. Abazov

We present results from a study of p-pbar -> W(gamma) + X events utilizing data corresponding to 0.7 fb^{-1} of integrated luminosity at sqrt(s) = 1.96 TeV collected by the D0 detector at the Fermilab Tevatron Collider. We set limits on anomalous WWgamma couplings at the 95% C.L. The one dimensional 95% C.L. limits are 0.49 < kappa_{gamma} < 1.51 and -0.12 <

A. T. Costa, R. B. Muniz, M. S. Ferreira

Magnetic moments dilutely dispersed in a metallic host tend to be coupled through the conduction electrons of the metal. This indirect exchange coupling, known to occur for a variety of magnetic materials embedded in several different metallic structures, is of rather long range, especially for low-dimensional structures like carbon nanotubes. Motivated by r

Zbigniew Chajecki, Mike Lisa

It is important to understand, in detail, two-pion correlations measured in p+p and d+A collisions. In particular, one wishes to understand the femtoscopic correlations, in order to compare to similar measurements in heavy ion collisions. However, in the low-multiplicity final states of these systems, global conservation laws generate significant N-body corr

Brian Jackson, Richard Greenberg, Rory Barnes

Extra-solar planets close to their host stars have likely undergone significant tidal evolution since the time of their formation. Tides probably dominated their orbital evolution once the dust and gas had cleared away, and as the orbits evolved there was substantial tidal heating within the planets. The tidal heating history of each planet may have contribu

Raphael Zentner

We study generalisations to the structure groups U(n) of the familiar (abelian) Seiberg-Witten monopole equations on a four-manifold $X$ and their moduli spaces. For $n=1$ one obtains the classical monopole equations. For $n > 1$ our results indicate that there should not be any non-trivial gauge-theoretical invariants which are obtained by the scheme `evalu

Raphael Zentner

A famous conjecture in gauge theory mathematics, attributed to Witten, suggests that the polynomial invariants of Donaldson are expressible in terms of the Seiberg-Witten invariants if the underlying four-manifold is of simple type. Mathematicians have sought a proof of the conjecture by means of a `cobordism program' involving $PU(2)$ monopoles. A higher ra

G. B. Lesovik

It this paper we consider various methods for measuring current fluctuations. It is shown, that the {\it temporal} zero-point fluctuations of current are measurable in a natural set-ups.

G. G. Williams, P. A. Milne, H. S. Park, S. D. Barthelmy

We provide an overview of the robotic Super-LOTIS (Livermore Optical Transient Imaging System) telescope and present results from gamma-ray burst (GRB) afterglow observations using Super-LOTIS and other Steward Observatory telescopes. The 0.6-m Super-LOTIS telescope is a fully robotic system dedicated to the measurement of prompt and early time optical emiss

G. B. Lesovik, R. Loosen

We consider a measurement of finite-frequency current fluctuations, using a resonance circuit as a model for the detector. We arrive at an expression for the measurable response in terms of the current-current correlators which differs from the standard (symmetrized) formula. The possibility of detection of vacuum fluctuations is discussed.

Johan Alwall, My-Phuong Le, Mariangela Lisanti, Jay G. Wacker

This letter describes how to perform searches over the complete kinematically-allowed parameter space for new pair-produced color octet particles that each subsequently decay into two jets plus missing energy at the Tevatron. This letter shows that current searches can miss otherwise discoverable spectra of particles due to CMSSM-motivated cuts. Optimizing t

Patrick Brosnan, Ramesh Sreekantan

We affirmatively answer a conjecture in the preprint ``Essential dimension and algebraic stacks,'' proving that the essential dimension of an abelian variety over a number field is infinite.

Simon Murphy

This management summary provides an outline of a commercial spreadsheet review process. The aim of this process is to ensure remedial or enhancement work can safely be undertaken on a spreadsheet with a commercially acceptable level of risk of introducing new errors.

M. Dillon, B. T. Gaensicke, A. Aungwerojwit, P. Rodriguez-Gil

We present time resolved CCD photometry of 15 cataclysmic variables (CVs) identified by the Sloan Digital Sky Survey (SDSS). The data were obtained as part of the 2004/05 International Time Programme on La Palma. We discuss the morphology of the light curves and the CV subtypes and give accurate orbital periods for 11 systems. Nine systems are found below th

Wenxin Ding, Nicholas E. Bonesteel, Kun Yang

In this paper we calculate the block entanglement entropies of spin models whose ground states have perfect antiferromagnetic or ferromagnetic long-range order. In the latter case the definition of entanglement entropy is extended to properly take into account the ground state degeneracy. We find in both cases the entropy grows logarithmically with the block

Ayush Gupta, Edward F. Redish, David Hammer

We investigate the dynamics of how graduate students coordinate their mathematics and physics knowledge within the context of solving a homework problem for a plasma physics survey course. Students were asked to obtain the complex dielectric function for a plasma with a specified distribution function and find the roots of that expression. While all the 16 p

Keith Bishop

Much of what EuSpRIG discusses is concerned with the integrity of individual spreadsheets. In businesses, interlocking spreadsheets are regularly used to fill functional gaps in core administrative systems. The growth and deployment of such integrated spreadsheet SYSTEMS raises the scale of issues to a whole new level. The correct management of spreadsheet s

Kevin Lu, E. E. Brodsky, H. P. Kavehpour

Fragile materials ranging from sand to fire-retardant to toothpaste are able to exhibit both solid and fluid-like properties across the jamming transition. Unlike ordinary fusion, systems of grains, foams and colloids jam and cease to flow under conditions that still remain unknown. Here we quantify jamming via a thermodynamic approach by accounting for the

Kevin J. Carlin

The setting is the representation theory of a simply connected, semisimple algebraic group over a field of positive characteristic. There is a natural transformation from the wall-crossing functor to the identity functor. The kernel of this transformation is a left exact functor. This functor and its first derived functor are evaluated on the global sections

Gilberto Corso, Aderaldo I. L. Araujo, Adriana M. Almeida

A recent problem in community ecology lies in defining structures behind matrices of species interactions. The interest in this area is to quantify the nestedness degree of the matrix after its maximal packing. In this work we evaluate nestedness using the sum of all distances of the occupied sites to the vertex of the matrix. We calculate the distance for t

Edward Lee

We review some recent results on the modularity of non-rigid Calabi-Yau threefolds.

D. S. Davis, H. B. Richer, J. Anderson, J. P. Brewer

Using Hubble Space Telescope (HST) observations of the globular cluster NGC6397, we constrain the cluster's binary fraction. The observations consist of two fields: the primary science field, a single ACS pointing centered approximately 5' from the cluster center; and the parallel field, a single WFPC2 field centered on the cluster center. Using the exquisit

R. K. S. Yadav, L. R. Bedin, G. Piotto, J. Anderson

The solar-age open cluster M67 (C0847+120, NGC2682) is a touchstone in studies of the old Galactic disk. Despite its outstanding role, the census of cluster membership for M67 at fainter magnitudes and their properties are not well-established. Using the proprietary and archival ESO data, we have obtained astrometric, photometric, and radial velocities of st

Eugene Vasiliev, Maxim Zelnikov

The evolution of dark matter in central areas of galaxies is considered (the Milky Way is taken as an example). It is driven by scattering off of dark matter particles by bulge stars, their absorption by the supermassive black hole and self-annihilation. This process is described by diffusion equation in the phase space of energy and angular momentum. The eq

R. H. K. Kadala, P. G. Mercadante, J. K. Mizukoshi, Xerxes Tata

The branching fraction for the decays of gluinos to third generation quarks is expected to be enhanced in classes of supersymmetric models where either third generation squarks are lighter than other squarks, or in mixed-higgsino dark matter models constructed to be in concordance with the measured density of cold dark matter. In such scenarios, gluino produ

Martin Sahlén, Pedro T. P. Viana, Andrew R. Liddle, A. Kathy Romer

We forecast the constraints on the values of sigma_8, Omega_m, and cluster scaling relation parameters which we expect to obtain from the XMM Cluster Survey (XCS). We assume a flat Lambda-CDM Universe and perform a Monte Carlo Markov Chain analysis of the evolution of the number density of galaxy clusters that takes into account a detailed simulated selectio

Gianluca Calcagni, Giuseppe Nardelli

We study a class of nonlocal systems which can be described by a local scalar field diffusing in an auxiliary radial dimension. As examples p-adic, open and boundary string field theory are considered on Minkowski, Friedmann-Robertson-Walker and Euclidean metric backgrounds. Starting from distribution-like initial field configurations which are constant almo

Juan Carlos Bueno Sanchez, Mar Bastero-Gil, Arjun Berera, Konstantinos Dimopoulos

We study the low-temperature limit of warm inflation in a hilltop model. This limit remains valid up to the end of inflation, allowing an analytic description of the entire inflationary stage. In the weak dissipative regime, if the kinetic density of the inflaton dominates after inflation, low scale inflation is attained with Hubble scale as low as 1 GeV. In

J. R. Dawson, N. Mizuno, T. Onishi, N. M. McClure-Griffiths

The "Carina Flare" supershell, GSH 287+04-17, is a molecular supershell originally discovered in 12CO(J=1-0) with the NANTEN 4m telescope. We present the first study of the shell's atomic ISM, using HI 21 cm line data from the Parkes 64m telescope Southern Galactic Plane Survey. The data reveal a gently expanding, ~ 230 x 360 pc HI supershell that shows stro

A. W. Shafter, J. R. A. Davenport, T. Güth, S. Kattner

Time-resolved CCD photometry is presented of the V~17 optical counterpart of the newly-discovered, hard-X-ray-emitting polar Swift J2619.4+2619. A total of ~20 hr of data obtained over five nights in various bandpasses (B, V, R, and I) reveals a strong quasi-sinusoidal modulation in the light curve at a best-fitting period of 0.1254 d (3.01 hr), which we ass

Yu. A Kuperin, R. R. Schastlivtsev

The paper is devoted to elaboration of a novel specific indicator based on the modified Holder exponents. This indicator has been used for forecasting critical points of financial time series and crashes of the USA stock market. The proposed approach is based on the hypothesis, which claims that before market critical points occur the dynamics of financial t

Luca Sanguinetti, Michele Morelli, H. Vincent Poor

An efficient scheme for initial ranging has recently been proposed by X. Fu et al. in the context of orthogonal frequency-division multiple-access (OFDMA) networks based on the IEEE 802.16e-2005 standard. The proposed solution aims at estimating the power levels and timing offsets of the ranging subscriber stations (RSSs) without taking into account the effe

Francesco Cellarosi

We prove the existence of the limiting distribution for the sequence of denominators generated by continued fraction expansions with even partial quotients, which were introduced by F. Schweiger and studied also by C. Kraaikamp and A. Lopes. Our main result is proven following the strategy used by Ya. Sinai and C. Ulcigrai in their proof of a similar renewal

A. I. Toth, C. P. Moca, O. Legeza, G. Zarand

We generalize the spectral sum rule preserving density matrix numerical renormalization group (DM-NRG) method in such a way that it can make use of an arbitrary number of not necessarily Abelian, local symmetries present in the quantum impurity system. We illustrate the benefits of using non-Abelian symmetries by the example of calculations for the T-matrix

R. Aloisio, V. Berezinsky, S. Grigorieva

We present a systematic study of different methods for the analytic calculation of ultra-high energy nuclei diffuse spectra. Nuclei propagating in the intergalactic space are photo-disintegrated and decrease their Lorentz factor due to the interaction with cosmic microwave background and extragalactic background light. We calculate the evolution trajectories

Chandan Kumar, Lawrence H. Friedman

Epitaxial self-assembled quantum dots (SAQDs) are of both technological and fundamental interest, but their reliable manufacture still presents a technical challenge. To better understand the formation, morphology and ordering of epitaxial self-assembled quantum dots (SAQDs), it is essential to have an accurate model that can aid further experiments and pred

Jiansong Gao, Miguel Daal, Peter Day, Benjamin Mazin

We present measurements of the temperature-dependent frequency shift of five niobium superconducting coplanar waveguide microresonators with center strip widths ranging from 3 $\mu$m to 50 $\mu$m, taken at temperatures in the range 100-800 mK, far below the 9.2 K transition temperature of niobium. These data agree well with the two-level system (TLS) theory.

Jack Raymond, David Saad

Composite systems, where couplings are of two types, a combination of strong dilute and weak dense couplings of Ising spins, are examined through the replica method. The dilute and dense parts are considered to have independent canonical disordered or uniform bond distributions; mixing the models by variation of a parameter $\gamma$ alongside inverse tempera

Pierre Gaspard, Thomas Gilbert

We consider the motion of many confined billiard balls in interaction and discuss their transport and chaotic properties. In spite of the absence of mass transport, due to confinement, energy transport can take place through binary collisions between neighbouring particles. We explore the conditions under which relaxation to local equilibrium occurs on time

L. Mouchliadis, A. L. Ivanov

We propose and analyze a k-filtering effect which gives rise to the drastic difference between the actual spatial coherence length of quasi-two-dimensional (quasi-2D) excitons or microcavity (MC) polaritons in planar nanostructures and that inferred from far-field optical measurements. The effect originates from the conservation of in-plane wavevector k in t

Nikodem J. Poplawski

A general affine connection has enough degrees of freedom to describe the classical gravitational and electromagnetic fields in the metric-affine formulation of gravity. The gravitational field is represented in the Lagrangian by the symmetric part of the Ricci tensor, while the classical electromagnetic field is represented geometrically by the tensor of ho

Sophie Morel

The goal of this paper is to calculate the trace of the composition of a Hecke correspondence and a (high enough) power of the Frobenius at a good place on the intersection cohomology of the Satake-Baily-Borel compactification of certain Shimura varieties, to stabilize the result for Shimura varieties associated to unitary groups over $\mathbb{Q}$ and to giv

Tamas Keviczky, Karl Henrik Johansson

We investigate convergence properties of a proposed distributed model predictive control (DMPC) scheme, where agents negotiate to compute an optimal consensus point using an incremental subgradient method based on primal decomposition as described in Johansson et al. [2006, 2007]. The objective of the distributed control strategy is to agree upon and achieve

Alex E. Bernardini, O. Bertolami

A perturbative approach for arbitrary choices of the equation of state of the universe is introduced in order to treat scenarios for mass varying neutrinos (MaVaN's) coupled to the dark sector. The generalized criterion for the applicability of such an approach is expressed through a constraint on the coefficient of the linear perturbation on the dark sector

Sandro Silva e Costa

In this work the modified Chaplygin gas is related to a cosmological scalar field. Analytical results, more general than the solutions previously shown in the literature, are presented for the case when the curvature is absent, and one entirely new particular result is shown for a case where there is curvature. Also, it is emphasized here that one interestin

M. Gomes, J. R. Nascimento, A. Yu. Petrov, A. J. da Silva

We study the possibility of establishing the dual equivalence between the noncommutative Maxwell-Chern-Simons theory and the noncommutative self-dual theory. It turns to be that whereas in the commutative case the Maxwell-Chern-Simons theory can be mapped into the sum of the self-dual theory and the Chern-Simons theory, in the noncommutative case such a mapp

E. Sabbi, J. S. Gallagher, L. J. Smith, D. F. de Mello

Deep images taken with the Wide Field Channel of the Advanced Camera for Surveys on board the Hubble Space Telescope provide the basis for study the resolved stellar population of the M81 companion dwarf irregular galaxy Holmberg IX. Based on color-magnitude diagrams the stellar population toward Holmberg IX contains numerous stars with ages of <~200 Myr as

Matthew Macauley, Henning S. Mortveit

Graph dynamical systems (GDSs) can be used to describe a wide range of distributed, nonlinear phenomena. In this paper we characterize cycle equivalence of a class of finite GDSs called sequential dynamical systems SDSs. In general, two finite GDSs are cycle equivalent if their periodic orbits are isomorphic as directed graphs. Sequential dynamical systems m

V. Del Duca, E. W. N. Glover

By taking the high-energy limit of the two-loop and the three-loop four-point amplitudes in the maximally supersymmetric N=4 Yang-Mill theory (MSYM), we test the validity of the loop expansion of the high-energy amplitude, beyond the next-to-leading-logarithmic (NLL) accuracy. We compute the three-loop Regge trajectory, and the two-loop and three-loop coeffi

Jorge Sotomayor, Luis Fernando Mello, Denis de Carvalho Braga

This paper pursues the study carried out by the authors in "Stability and Hopf bifurcation in a hexagonal governor system", focusing on the codimension one Hopf bifurcations in the hexagonal Watt governor differential system. Here are studied the codimension two, three and four Hopf bifurcations and the pertinent Lyapunov stability coefficients and bifurcati

Alexander J. Silenko

A comparative analysis of the Mathisson-Papapetrou and Pomeransky-Khriplovich equations is presented. Motion of spinning particles and their spins in gravitational fields and noninertial frames is considered. The angular velocity of spin precession defined by the Pomeransky-Khriplovich equations depends on the choice of the tetrad. The connection of such a d

R. El Boubsi, O. Usmani, Ya. M. Blanter

We investigate strong mechanical feedback for the single-electron tunneling device coupled to an underdamped harmonic oscillator in the high-frequency case, when the mechanical energy of the oscillator exceeds the tunnel rate, and for weak coupling. In the strong feedback regime, the mechanical oscillations oscillated by the telegraph signal from the SET in

Qiang Zhang, Hiroki Takesue, Carsten Langrock, Xiuping Xie

We experimentally observed a Hong-Ou-Mandle dip with photon pairs generated in a periodically poled reverse-proton-exchange lithium niobate waveguide with an integrated mode demultiplexer at a wavelength of 1.5 um. The visibility of the dip in the experiment was 80% without subtraction of any noise terms at a peak pump power of 4.4 mW. The new technology dev

J. Tempere, S. N. Klimin, J. T. Devreese, V. V. Moshchalkov

Singlet pairing in a Fermi superfluid is frustrated when the amounts of fermions of each pairing partner are unequal. The resulting `imbalanced superfluid' has been realized experimentally for ultracold atomic gases with s-wave interactions. Inspired by high-temperature superconductivity, we investigate the case of d-wave interactions, and find marked differ

J. R. Maund

Linear spectropolarimetry is a ``photon-hungry'' observing technique, requiring a specific sequence of observations to determine the Stokes Q and U parameters. For dual-beam spectropolarimeters, the parameters can be ideally determined using observations at N=2 retarder plate positions. The additional polarization signal introduced by instrumental effects re

Boris Khesin, Paul Lee

We describe first integrals of geostrophic equations, which are similar to the enstrophy invariants of the Euler equation for an ideal incompressible fluid. We explain the geometry behind this similarity, give several equivalent definitions of the Poisson structure on the space of smooth densities on a symplectic manifold, and show how it can be obtained via

Deirdre Shoemaker, Birjoo Vaishnav, Ian Hinder, Frank Herrmann

We present a study of the gravitational waveforms from a series of spinning, equal-mass black hole binaries focusing on the harmonic content of the waves and the contribution of the individual harmonics to the signal-to-noise ratio. The gravitational waves were produced from two series of evolutions with black holes of initial spins equal in magnitude and an

Sergei Sergeenkov, Marcel Ausloos

A possible scenario for an ac Josephson effect initiated by the flow of dislocations through a mechanically loaded but electrically unbiased superconductor is proposed. The characteristic voltages due to the motion of dislocations in loaded (under the applied stress of 10^7N/m^2) YBCO crystals are estimated to be of the order of a few picovolts (which corres

Eiichi Matsuhashi, Vesko Valov

We say that a metrizable space $M$ is a Krasinkiewicz space if any map from a metrizable compactum $X$ into $M$ can be approximated by Krasinkiewicz maps (a map $g\colon X\to M$ is Krasinkiewicz provided every continuum in $X$ is either contained in a fiber of $g$ or contains a component of a fiber of $g$). In this paper we establish the following property o

G. Trimarchi, I. Leonov, N. Binggeli, Dm. Korotin

We present a joint implementation of dynamical-mean-field theory (DMFT) with the pseudopotential plane-wave approach, via Wannier functions, for the determination of the electronic properties of strongly correlated materials. The scheme uses, as input for the DMFT calculations, a tight-binding Hamiltonian obtained from the plane-wave calculations by projecti

Charles Knessl, Diego Dominici

We analyze asymptotically a differential-difference equation, that arises in a Markov-modulated fluid model. We use singular perturbation methods to analyze the problem with appropriate scalings of the two state variables. In particular, the ray method and asymptotic matching are used.

Anne Pellerin, Martin J. Meyer, Jason Harris, Daniela Calzetti

We present the first results of a new technique to detect, locate, and characterize young dissolving star clusters. Using HST/ACS archival images of the nearby galaxy IC2574, we performed stellar PSF photometry and selected the most massive stars as our first test sample. We used a group-finding algorithm on the selected massive stars to find cluster candida

Marco Brunella

These are lecture notes for a course to be held. They provide a full discussion of certain analytic aspects of the uniformisation theory of (singular) holomorphic foliations by curves on compact Kaehler manifolds, with emphasis on their consequences on positivity properties of the corresponding canonical bundles.

Guido Pezzini

Let G be a complex semisimple linear algebraic group, and X a wonderful G-variety. We determine the connected automorphism group of X and we calculate Luna's invariants of X under its action.

Rouzbeh Allahverdi, Anupam Mazumdar

In this clarifying note we discuss the late decay of an Affleck-Dine condensate by providing a no-go theorem that attributes to conserved global charges which are identified by the net particle number in fields which are included in the flat direction(s). For a rotating condensate, this implies that: (1) the net baryon/lepton number density stored in the con

L. Steinke, D. Schuh, M. Bichler, G. Abstreiter

Transport studies of a bent quantum Hall junction at integer filling factors show strongly insulating states at higher fields. In this paper we analyze the strongly insulating behavior as a function of temperature T and dc bias V, in order to classify the localization mechanisms responsible for the insulating state. The temperature dependence suggests a cros

G. Falqui, G. Ortenzi

We discuss how the Camassa-Holm hierarchy can be framed within the geometry of the Sato Grassmannian.

A. Marco Saitta, Michele Lazzeri, Matteo Calandra, Francesco Mauri

The occurrence of non-adiabatic effects in the vibrational properties of metals have been predicted since the 60's, but hardly confirmed experimentally. We report the first fully \emph{ab initio} calculations of non-adiabatic frequencies of a number of layer and conventional metals. We suggest that non-adiabatic effects can be a feature of the vibrational Ra

A. Winnberg, D. Engels, J. Brand, L. Baldacci

We wish to understand the reasons for the strong variability of H2O masers in circumstellar shells of late-type stars. We monitored RX Boo and SV Peg in the 22-GHz maser line of water vapour with single-dish telescopes. The monitoring period covered two decades for RX Boo (1987 -- 2007) and 12 years for SV Peg (1990 -- 1995, 2000 -- 2007). In addition, maps

V. V. Kirichenko, B. V. Novikov

The Brauer monoid is studied by the notion of 0-cohomology. We investigate the impact of invertible elements of modifications on the structure of the Brauer monoid, especially for finite fields.

A. Kuzmin, B. Ya. Losovsky, C. A. Jordan, F. Graham Smith

In separate series of observations of the Crab pulsar, pulse broadening due to scattering was measured at 111 MHz, and variations of dispersion due to pulse delay were measured at higher radio frequencies. In a remarkable event lasting 200 days a large increase occurred in both parameters and with similar time signatures. The increases in scattering and disp

Vincenzo Branchina, Hugo Faivre, Vincent Pangon

By following previous work on this subject, we investigate the issue of the instability of the electroweak vacuum against the top loop corrections by performing an accurate analysis of a Higgs-Yukawa model. We find that, when the physical cutoff is properly implemented in the theory, the potential does not exhibit any instability. Moreover, contrary to recen

G. Anetsberger, R. Rivière, A. Schliesser, O. Arcizet

Cavity-enhanced radiation-pressure coupling of optical and mechanical degrees of freedom gives rise to a range of optomechanical phenomena, in particular providing a route to the quantum regime of mesoscopic mechanical oscillators. A prime challenge in cavity optomechanics has however been to realize systems which simultaneously maximize optical finesse and

P. A. James, J. H. Knapen, N. S. Shane, I. K. Baldry

We present an analysis of the star formation properties of field galaxies within the local volume out to a recession velocity limit of 3000 km/s. A parent sample of 863 star-forming galaxies is used to calculate a B-band luminosity function. This is then populated with star formation information from a subsample of 327 galaxies, for which we have H alpha ima

Javier Munarriz, Juan J. Mazo, Fernando Falo

A simple flashing ratchet model in two dimensions is proposed to simulate the hand-over-hand motion of two head molecular motors like kinesin. Extensive Langevin simulations of the model are performed. Good qualitative agreement with the expected behavior is observed. We discuss different regimes of motion and efficiency depending of model parameters.

M. I. Dykman, V. N. Smelyanskiy

Dynamics of a system that performs a large fluctuation to a given state is essentially deterministic: the distribution of fluctuational paths peaks sharply at a certain optimal path along which the system is most likely to move. For the general case of a system driven by colored Gaussian noise, we provide a formulation of the variational problem for optimal

Daniel Alpay, Mamadou Mboup

We give a new characterization of character-automorphic Hardy spaces of order 2 and of their contractive multipliers in terms of de Branges Rovnyak spaces. Keys tools in our arguments are analytic extension and a factorization result for matrix-valued analytic functions due to Leech.

P. Achenbach, L. Nungesser, J. Pochodzalla

Multi-layered scintillating fibre arrays read-out are commonly used as high resolution charged particle hodoscopes. Fibres of a column along the geometrical trajectory of incident particles are typically grouped to one pixel of a multi-channel read-out device. In some applications the incident particles will cross the detection plane with large angles w.r.t.

Hael Collins, R. Holman

We study some of the roles for unparticles in an inflationary universe. Unparticles by themselves are not appropriate for generating the primordial perturbations since their power spectrum does not match what has been inferred from observations. In fact, when the scaling dimension for the unparticles exceeds three-halves, the unparticle power spectrum diverg

S. L. Cornish, N. G. Parker, A. M. Martin, T. E. Judd

We propose the use of bright matter-wave solitons formed from Bose-Einstein condensates with attractive interactions to probe and study quantum reflection from a solid surface at normal incidence. We demonstrate that the presence of attractive interatomic interactions leads to a number of advantages for the study of quantum reflection. The absence of dispers

A. A. Kostin, B. V. Novikov

In this work we construct an extension for the category of 0-modules by analogy with [H.-J. Baues and G. Wirshing, Cohomology of small categories, J. Pure Appl. Algebra, 38(1985), 187-211]. The 0-cohomology functor becomes a derived functor in the extended category. As an application of this construction we calculate the cohomological dimension of so-called

S. A. Mikhailov, K. Ziegler

Graphene is a recently discovered carbon based material with unique physical properties. This is a monolayer of graphite, and the two-dimensional electrons and holes in it are described by the effective Dirac equation with a vanishing effective mass. As a consequence, electromagnetic response of graphene is predicted to be strongly non-linear. We develop a q

Anirban Chakraborti, Marco Patriarca

We discuss the equivalence between kinetic wealth-exchange models, in which agents exchange wealth during trades, and mechanical models of particles, exchanging energy during collisions. The universality of the underlying dynamics is shown both through a variational approach based on the minimization of the Boltzmann entropy and a complementary microscopic a

Martin Ilgner, Richard P. Nelson

Protostellar accretion discs have cool, dense midplanes where externally originating ionisation sources such as X-rays or cosmic rays are unable to penetrate. This suggests that for a wide range of radii, MHD turbulence can only be sustained in the surface layers where the ionisation fraction is sufficiently high. A dead zone is expected to exist near the mi

Luke Drury, Felix Aharonian

We discuss the reported detection by the MILAGRO experiment of localised hot spots in the cosmic ray arrival distribution and the difficulty of interpreting these observations. A model based on secondary neutron production in the heliotail is shown to fail. An alternative model based on loss-cone leakage through a magnetic trap from a local source region is

Bhavin Patel, Ajay Kumar Rai, P. C. Vinodkumar

Heavy flavor baryons containing single and double charm (beauty) quarks with light flavor combinations are studied using the hyper central description of the three-body problem. The confinement potential is assumed as hyper central coulomb plus power potential with power index $\upsilon$. The ground state masses of the heavy flavor, $J^P={1/2}^+$ and ${3/2}^

J. -M. Virey, D. Talon-Esmieu, A. Ealet, P. Taxil

Constraining simultaneously the Dark Energy(DE) equation of state and the curvature of the Universe is difficult due to strong degeneracies. To circumvent this problem when analyzing data it is usual to assume flatness to constrain DE, or conversely, to assume that DE is a cosmological constant to constrain curvature. In this paper, we quantify the impact of

Ulrich Haboeck, Vyacheslav Kulagin

We consider continuous extensions of minimal rotations on a locally connected compact group X by arbitrary locally compact Lie groups and prove regularity (i.e. the existence of orbit closures which project onto the whole basis X) in certain special situations beyond the already known nilpotent case. We further discuss an open question on cocycles acting on

Karl Tordrup, Antonio Negretti, Klaus Molmer

We propose that a single mesoscopic ensemble of trapped polar molecules can support a "holographic quantum computer" with hundreds of qubits encoded in collective excitations with definite spatial phase variations. Each phase pattern is uniquely addressed by optical Raman processes with classical optical fields, while one- and two-qubit gates are accomplishe

V. A. Atanasov, V. S. Gerdjikov, G. G. Grahovski, N. A. Kostov

A three-component nonlinear Schrodinger-type model which describes spinor Bose-Einstein condensate (BEC) is considered. This model is integrable by the inverse scattering method and using Zakharov-Shabat dressing method we obtain three types of soliton solutions. The multi-component nonlinear Schrodinger type models related to symmetric spaces C.I Sp(4)/U(2)

Javier R. Goicoechea, Olivier Berne, Maryvonne Gerin, Christine Joblin

We present the detection and characterization of a peculiar low-mass protostar (IRAS 22129+7000) located ~0.4 pc from Ced 201 Photodissociation Region (PDR) and ~0.2 pc from the HH450 jet. The cold circumstellar envelope surrounding the object has been mapped through its 1.2 mm dust continuum emission with IRAM-30m/MAMBO. The deeply embedded protostar is cle

Mirela Damian

It is a standing open question to decide whether the Yao-Yao structure for unit disk graphs (UDGs) is a length spanner of not. This question is highly relevant to the topology control problem for wireless ad hoc networks. In this paper we make progress towards resolving this question by showing that the Yao-Yao structure is a length spanner for UDGs of bound

K. Pappert, C. Gould, M. Sawicki, J. Wenisch

This paper discusses transport methods for the investigation of the (Ga,Mn)As magnetic anisotropy. Typical magnetoresistance behaviour for different anisotropy types is discussed, focusing on an in depth discussion of the anisotropy fingerprint technique and extending it to layers with primarily uniaxial magnetic anisotropy. We find that in all (Ga,Mn)As fil

Martin Hömberg, Marcus Müller

Mean-field techniques provide a rather accurate description of single-chain conformations in spatially inhomogeneous polymer systems containing interfaces or surfaces. Intermolecular correlations, however, are not described by the mean-field approach and information about the distribution of distance between different molecules is lost. Based on the knowledg

Timm Krueger, Matthias Neubert, Christof Wetterich

We investigate non-linear, spherically symmetric solutions to the coupled system of a quintessence field and Einstein gravity. In the presence of a scalar potential, we find regular solutions that to an outside observer very closely resemble Schwarzschild black holes. However, these cosmon lumps have neither a horizon nor a central singularity. A stability a

V. S. Gerdjikov, A. Kostov, T. I. Valchev

A three- and five-component nonlinear Schrodinger-type models, which describe spinor Bose-Einstein condensates (BEC's) with hyperfine structures F=1 and F=2 respectively, are studied. These models for particular values of the coupling constants are integrable by the inverse scattering method. They are related to symmetric spaces of BD.I-type SO(2r+1)/(SO(2)

Osame Kinouchi, Rosa W. Diez-Garcia, Adriano J. Holanda, Pedro Zambianchi

Food is an essential part of civilization, with a scope that ranges from the biological to the economic and cultural levels. Here we study the statistics of ingredients and recipes taken from Brazilian, British, French, and Medieval cookbooks. We find universal distributions with scale invariant behavior. We propose a copy-mutate process to model culinary ev

M. Tucci, J. A. Rubiño-Martin, R. Rebolo, R. Genova-Santos

We present an analysis of the spectral properties of the extragalactic radio sources in the nearly-complete VSA sample at 33GHz. Data from different surveys are used to study source spectra between 1.4 and 33GHz. We find that, in general, spectra can not be well described by a single power law in the range of frequencies considered. In particular, most of th

B. Czerny, A. Siemiginowska, A. Janiuk, A. C. Gupta

We select a sample of 10 radio-quiet quasars with confirmed intranight optical variability and with available X-ray data. We compare the variability properties and the broad band spectral constraints to the predictions of intranight variability by three models: (i) irradiation of an accretion disk by a variable X-ray flux (ii) an accretion disk instability (

P. D. Andreev

Let $X$ be a non-compact proper Busemann space. We introduce a collection of binary relations on its ideal boundaries generalizing comparison of Tits metric with two key values $\pi$ and $\pi/2$. This allows to use properties of Tits metric known for CAT(0)-space without metric itself.