February 2008 arXiv papers

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 <

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

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

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

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

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&#39;s binary fraction. The observations consist of two fields: the primary science field, a single ACS pointing centered approximately 5&#39; from the cluster center; and the parallel field, a single WFPC2 field centered on the cluster center. Using the

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

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

The &#34;Carina Flare&#34; 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&#39;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 tha

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

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

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 $μ$m to 50 $μ$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. Fit

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 $γ$ alongside inverse temperature

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

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

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&#39;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 se

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

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 &#34;Stability and Hopf bifurcation in a hexagonal governor system&#34;, 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 b

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

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&#39;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

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&#39;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 vibrationa

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

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

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

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 &#34;holographic quantum computer&#34; 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 acc

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

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 $π$ and $π/2$. This allows to use properties of Tits metric known for CAT(0)-space without metric itself.

Lars Fritz, Joerg Schmalian, Markus Mueller, Subir Sachdev

We describe electrical transport in ideal single-layer graphene at zero applied bias. There is a crossover from collisionless transport at frequencies larger than k_B T/hbar (T is the temperature) to collision-dominated transport at lower frequencies. The d.c. conductivity is computed by the solution of a quantum Boltzmann equation. Due to a logarithmic sing

S. A. Emelyanov

Further experiments showed the incorrectness of proposed interpretation.

L. Yungelson, J. -P. Lasota

We consider evolutionary models for the population of short-period (<10 hr) low-mass black-hole binaries (LMBHBs) and compare them with observations of soft X-ray transients (SXTs). We show that assuming strongly reduced magnetic braking (as suggested by us before for low-mass semidetached binaries) the calculated masses and effective temperatures of seconda

Itaï Ben Yaacov

We give a general framework for the treatment of perturbations of types and structures in continuous logic, allowing to specify which parts of the logic may be perturbed. We prove that separable, elementarily equivalent structures which are approximately $\aleph_0$-saturated up to arbitrarily small perturbations are isomorphic up to arbitrarily small perturb

Philippe Delorme, Xavier Delfosse, Loic Albert, Etienne. Artigau

We report the discovery of CFBDS J005910.90-011401.3 (hereafter CFBDS0059), the coolest brown dwarf identified to date. We found CFBDS0059 using i&#39; and z&#39; images from the Canada-France-Hawaii Telescope (CFHT), and present optical and near-infrared photometry, Keck laser guide star adaptive optics imaging, and a complete near-infrared spectrum, from 1

Anton Galajinsky, Olaf Lechtenfeld, Kirill Polovnikov

N=4 superconformal multi-particle quantum mechanics on the real line is governed by two prepotentials, U and F, which obey a system of partial differential equations linear in U and generalizing the Witten-Dijkgraaf-Verlinde-Verlinde (WDVV) equation for F. Putting U=0 yields a class of models (with zero central charge) which are encoded by the finite Coxeter

Masahiro N. Machida

Cloud evolution for various metallicities is investigated by three-dimensional nested grid simulations, in which the initial ratio of rotational to gravitational energy of the host cloud β_0 (=10^-1 - 10^-6) and cloud metallicity Z (=0 - Z_\odot) are parameters. Starting from a central number density of n = 10^4 cm^-3, cloud evolution for 48 models is calcul

Luis J. Alias, Ana Hurtado, Vicente Palmer

Some analysis on the Lorentzian distance in a spacetime with controlled sectional (or Ricci) curvatures is done. In particular, we focus on the study of the restriction of such distance to a spacelike hypersurface satisfying the Omori-Yau maximum principle. As a consequence, and under appropriate hypotheses on the (sectional or Ricci) curvatures of the ambie

Christopher Gaul, Cord Axel Müller

We consider elementary excitations of an interacting Bose-Einstein condensate in the mean-field framework. As a building block for understanding the dynamics of systems comprising interaction and disorder, we study the scattering of Bogoliubov excitations by a single external impurity potential. A numerical integration of the Gross-Pitaevskii equation shows

Takayuki Nozawa, Toshiyuki Kondo

Several cellular automata (CA) models have been developed to simulate self-organization of multiple levels of structures. However, they do not obey microscopic reversibility and conservation laws. In this paper, we describe the construction of a reversible lattice molecular automata (RLMA) model, which simulates molecular interaction and self-organization of

J. Spinelly, E. R. Bezerra de Mello

In this paper we investigate the vacuum polarization effects associated with quantum fermionic charged fields in a generalized $(d+1)-$dimensional cosmic string space-times considering the presence of a magnetic flux along the string. In order to develop this analysis we calculate a general expression for the respective Green function, valid for several diff

Christian Kassel, Christophe Reutenauer

We define a self-map Pal: F_2 --> F_2 of the free group on two generators a, b, using automorphisms of F_2 that form a group isomorphic to the braid group B_3. The map Pal restricts to de Luca&#39;s right iterated palindromic closure on the submonoid generated by a, b, and is continuous for the profinite topology on F_2. The values of Pal are palindromes and

Ronald Brown

The classifying space of a crossed complex generalises the construction of Eilenberg-Mac Lane spaces. We show how the theory of fibrations of crossed complexes allows the analysis of homotopy classes of maps from a free crossed complex to such a classifying space. This gives results on the homotopy classification of maps from a CW-complex to the classifying

A. A. Abdujabbarov, B. J. Ahmedov, V. G. Kagramanova

The exact solution for the electromagnetic field occuring when the Kerr-Taub-NUT compact object is immersed (i) in an originally uniform magnetic field aligned along the axis of axial symmetry (ii) in dipolar magnetic field generated by current loop has been investigated. Effective potential of motion of charged test particle around Kerr-Taub-NUT gravitation

Vladimir Baranovsky

We consider the algebraization problem for principal bundles with reductive structure group, defined on the complement of a closed subset Z in a proper formal scheme. We show that, when Z is of codimension at least 3, an algebraization always exists. For codimension 2 we show that an algebraization exists precisely when a certain additional condition is sati

R. Bernabei, P. Belli, F. Cappella, R. Cerulli

Some extensions of the Standard Model provide Dark Matter candidate particles with sub-GeV mass. These Light Dark Matter particles have been considered for example in Warm Dark Matter scenarios (e.g. the keV scale sterile neutrino, axino or gravitino). Moreover MeV scale DM candidates have been proposed in supersymmetric models and as source of the 511 keV l

Brendan Farrell, Thomas Strohmer

We consider linear time-varying channels with additive white Gaussian noise. For a large class of such channels we derive rigorous estimates of the eigenvalues of the correlation matrix of the effective channel in terms of the sampled time-varying transfer function and, thus, provide a theoretical justification for a relationship that has been frequently obs

P. Marconcini, M. Macucci, G. Iannaccone, B. Pellegrini

We report the results of an analysis, based on a straightforward quantum-mechanical model, of shot noise suppression in a structure containing cascaded tunneling barriers. Our results exhibit a behavior that is in sharp contrast with existing semiclassical models for this particular type of structure, which predict a limit of 1/3 for the Fano factor as the n

Francesco Buscemi

The action of a channel on a quantum system, when non trivial, always causes deterioration of initial quantum resources, understood as the entanglement initially shared by the input system with some reference purifying it. One effective way to measure such a deterioration is by measuring the loss of coherent information, namely the difference between the ini

Shane T. Jensen, Kenneth E. Shirley, Abraham J. Wyner

The use of statistical modeling in baseball has received substantial attention recently in both the media and academic community. We focus on a relatively under-explored topic: the use of statistical models for the analysis of fielding based on high-resolution data consisting of on-field location of batted balls. We combine spatial modeling with a hierarchic

Andrew C. Doherty, Stephen D. Bartlett

Quantum computation can proceed solely through single-qubit measurements on an appropriate quantum state, such as the ground state of an interacting many-body system. We investigate a simple spin-lattice system based on the cluster-state model, and by using nonlocal correlation functions that quantify the fidelity of quantum gates performed between distant q

Xiaoyang Gu, Jack H. Lutz, Elvira Mayordomo

We exhibit a polynomial time computable plane curve GAMMA that has finite length, does not intersect itself, and is smooth except at one endpoint, but has the following property. For every computable parametrization f of GAMMA and every positive integer n, there is some positive-length subcurve of GAMMA that f retraces at least n times. In contrast, every co

Kei Takeuchi, Masayuki Kumon, Akimichi Takemura

We study multistep Bayesian betting strategies in coin-tossing games in the framework of game-theoretic probability of Shafer and Vovk (2001). We show that by a countable mixture of these strategies, a gambler or an investor can exploit arbitrary patterns of deviations of nature&#39;s moves from independent Bernoulli trials. We then apply our scheme to asset

Andreas Nunnenkamp, Ana Maria Rey

We investigate the effects of rotation on one-dimensional ultracold bosons confined to optical ring lattices. First, we show that there exists a critical rotation frequency at which the ground state of a weakly-interacting and integer-filled atomic gas is fragmented into a macroscopic superposition state with different circulation. Second, we point out sever

Moustapha Diaby

This paper has been withdrawn because Theorem 21 and Corollary 22 are in error; The modeling idea is OK, but it needs 9-dimensional variables instead of the 8-dimensional variables defined in notations 6.9. Examples of the correct model (with 9-index variables) are: (1) Diaby, M., &#34;Linear Programming Formulation of the Set Partitioning Problem,&#34; Inte

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

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

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&#39; involving $PU(2)$ monopoles. A highe

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.

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

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.

Patrick Brosnan, Ramesh Sreekantan

We affirmatively answer a conjecture in the preprint ``Essential dimension and algebraic stacks,&#39;&#39; 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.

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

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

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.

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

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

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

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

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

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

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

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&#39; 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 di

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

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

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.

G. Falqui, G. Ortenzi

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

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

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

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