February 2008 arXiv papers — page 4

Christos Tryfonas, Dimitris Papamichail, Andrew Mehler, Steven Skiena

We examine the problem of accepting a new request for a pre-stored VBR video stream that has been smoothed using any of the smoothing algorithms found in the literature. The output of these algorithms is a piecewise constant-rate schedule for a Variable Bit-Rate (VBR) stream. The schedule guarantees that the decoder buffer does not overflow or underflow. The

Giovanni Falcone

The bare-dressed technique is, for the first time, used in collision theory. The approach is valid for classical as well for quantum binary elastic collisions in the non relativistic regime. The same formalism can be used for inelastic collisions, when the particles undergo only a change of their internal quantum states during the collision process. All kine

A. V. Chubukov, M. R. Norman

Recent Raman scattering data in B_{1g} and B_{2g} geometries in the superconducting state of underdoped cuprates were interpreted as evidence for two distinct energy gaps. We argue that these data can be equally well explained within a one gap scenario if final state interactions are taken into account. In particular, we show that they can account for the di

I. C. Shih, T. J. Maccarone, A. Kundu, S. E. Zepf

We present a study of the X-ray spectral properties of the highly variable X-ray emitting black hole in a globular cluster in the elliptical galaxy NGC 4472. The XMM-Newton spectrum of the source in its bright epoch is well described by a multiple blackbody model with a characteristic temperature $kT_{in}\approx$ 0.2 keV. The spectrum of an archival Chandra

P. Kocabova, P. Stovicek

We consider an invariant quantum Hamiltonian $H=-Δ_{LB}+V$ in the $L^{2}$ space based on a Riemannian manifold $\tilde{M}$ with a countable discrete symmetry group $Γ$. Typically, $\tilde{M}$ is the universal covering space of a multiply connected Riemannian manifold $M$ and $Γ$ is the fundamental group of $M$. On the one hand, following the basic step of th

Linhua Jiang, Xiaohui Fan, M. Vestergaard

We report on 293 quasars with strong NIV] lambda 1486 or NIII] lambda 1750 emission lines (rest-frame equivalent width > 3 Å) at 1.7 < z < 4.0 selected from the Sloan Digital Sky Survey (SDSS) Fifth Data Release. These nitrogen-rich (N-rich) objects comprise ~1.1% of the SDSS quasars. The comparison between the N-rich quasars and other quasars shows that the

Rajiv Soundararajan, Sriram Vishwanath

In this paper, the sum capacity of the Gaussian Multiple Input Multiple Output (MIMO) Cognitive Radio Channel (MCC) is expressed as a convex problem with finite number of linear constraints, allowing for polynomial time interior point techniques to find the solution. In addition, a specialized class of sum power iterative waterfilling algorithms is determine

R. Keith Ellis, Walter T. Giele, Zoltan Kunszt

The unitarity method for calculating one-loop amplitudes provides algorithms of polynomial complexity. This is primarily beneficial for the computation of multi-leg one loop amplitudes and it is therefore of great interest to develop a numerical implementation of the unitarity method. We describe a recently-developed, efficient, semi-numerical unitarity meth

J. -L. Lecouey, N. A. Orr, F. M. Marques, N. L. Achouri

The low-lying level structure of the unbound system $^{16}$B has been investigated via single-proton removal from a 35 MeV/nucleon $^{17}$C beam. The coincident detection of the beam velocity $^{15}$B fragment and neutron allowed the relative energy of the in-flight decay of $^{16}$B to be reconstructed. The resulting spectrum exhibited a narrow peak some 85

A. Mallios, P. P. Ntumba

Given an arbitrary sheaf $\mathcal{E}$ of $\mathcal{A}$-modules (or $\mathcal{A}$-module in short) on a topological space $X$, we define \textit{annihilator sheaves} of sub-$\mathcal{A}$-modules of $\mathcal{E}$ in a way similar to the classical case, and obtain thereafter the analog of the \textit{main theorem}, regarding classical annihilators in module th

M. F. Bietenholz

VLBI is the only technology that will allow sub-milliarcsecond resolution imaging in the near future. As such, it is the only way to image expanding supernovae in nearby galaxies. Such images potentially allow us to study the early evolution of neutron stars or black holes left behind by core-collapse supernovae, the circumstellar wind history of the superno

A. Carrassi, S. Vannitsem, C. Nicolis

Data assimilation schemes are confronted with the presence of model errors arising from the imperfect description of atmospheric dynamics. These errors are usually modeled on the basis of simple assumptions such as bias, white noise, first order Markov process. In the present work, a formulation of the sequential extended Kalman filter is proposed, based on

V. Gogokhia

The physical meaning of a mass gap introduced by Jaffe and Witten is to be responsible for the large-scale (low-energy/momentum), i.e., the non-perturbative structure of the true QCD vacuum. In order to make the existence of a mass gap pefrectly clear it is defined as the difference between the regularized full gluon self-energy and its subtracted (also regu

M. Ausloos

A comparison of two english texts from Lewis Carroll, one (Alice in wonderland), also translated into esperanto, the other (Through a looking glass) are discussed in order to observe whether natural and artificial languages significantly differ from each other. One dimensional time series like signals are constructed using only word frequencies (FTS) or word

C. Gutierrez, S. Lloyd, B. Pires

There exist uniquely ergodic affine interval exchange transformations of [0,1] with flips having wandering intervals and such that the support of the invariant measure is a Cantor set.

G. Contopoulos, M. Harsoula

We distinguish two types of stickiness in systems of two degrees of freedom (a) stickiness around an island of stability and (b) stickiness in chaos, along the unstable asymptotic curves of unstable periodic orbits. We studied these effects in the standard map with a rather large nonlinearity K=5, and we emphasized the role of the asymptotic curves U, S from

C. Gould, S. Mark, K. Pappert, G. Dengel

This paper reports on a detailed magnetotransport investigation of the magnetic anisotropies of (Ga,Mn)As layers produced by various sources worldwide. Using anisotropy fingerprints to identify contributions of the various higher order anisotropy terms, we show that the presence of both a [100] and a [110] uniaxial anisotropy in addition to the primary ([100

H. Kashiwaya, T. Matsumoto, S. Kashiwaya, H. Shibata

Energy level quantization (ELQ) is studied to clarify the macroscopic quantum dynamics of the d-wave Josephson junction (JJ). The influences of the nodal quasiparticles of d-wave superconductivity on the damping effect are numerically evaluated on the basis of a phenomenological model. The calculation, based on realistic parameters for a Bi2Sr2CaCu2O8+d (Bi2

S. Thorwirth, M. E. Harding, D. Muders, J. Gauss

High-level quantum-chemical calculations are reported at the MP2 and CCSD(T) levels of theory for the equilibrium structure and the harmonic and anharmonic force fields of diacetylene, HCCCCH. The calculations were performed employing Dunning&#39;s hierarchy of correlation-consistent basis sets cc-pVXZ, cc-pCVXZ, and cc-pwCVXZ, as well as the ANO2 basis set

Gernot J. Pauschenwein, Gerhard Kahl

We give evidence that particles interacting via the simple, radially symmetric square-shoulder potential can self-organize in highly complex, low-symmetry lattices, forming thereby clusters, columns, or lamellae; only at high pressure compact, high-symmetry structures are observed. Our search for these ordered equilibrium structures is based on ideas of gene

Solomija Buk, Ján Mačutek, Andrij Rovenchak

We investigate the grapheme-phoneme relation in Ukrainian and some properties of the Ukrainian version of the Cyrillic alphabet.

S. G. Lebedev

This review is described some new results in the studies of anomalous electromagnetic of thin carbon films. Starting with historical sketch of studies of superconductivity and electromagnetic in carbonaceous materials the efforts of such persons as the Nobel Prize winners Vitaly L.Ginzburg and W.A.Little, the Polish outstanding scientist K.Antonowicz, the Am

J. Kuipers, G. T. Barkema

In many systems, the time scales of the microscopic dynamics and macroscopic dynamics of interest are separated by many orders of magnitude. Examples abound, for instance nucleation, protein folding, and chemical reactions. For these systems, direct simulation of phase space trajectories does not efficiently determine most physical quantities of interest. Th

Guillaume Aubrun

The concept of $\e$-randomizing quantum channels has been introduced by Hayden, Leung, Shor and Winter in connection with approximately encrypting quantum states. They proved using a discretization argument that sets of roughly $d \log d$ random unitary operators provide examples of such channels on $\C^d$. We show that a simple trick improves the efficiency

Christine Plumejeaud, Jean-Marc Vincent, Claude Grasland, Jérôme Gensel

The HyperCarte research group wishes to offer a new cartographic tool for spatial analysis of social data, using the potential smoothing method. The purpose of this method is to view the spreading of phenomena&#39;s in a continuous way, at a macroscopic scale, basing on data sampled on administrative areas. We aim to offer an interactive tool, accessible via

Eric Gautier

Synthetic indices are used in Economics to measure various aspects of monetary inequalities. These scalar indices take as input the distribution over a finite population, for example the population of a specific country. In this article we consider the case of the French 2004 Wealth survey. We have at hand a partial measurement on the distribution of interes

Aïssa Allaoui, Suong V. Hoa, Martin D. Pugh

Carbon nanofibres (CNF) were dispersed into an epoxy resin using a combination of ultrasonication and mechanical mixing. The electronic transport properties of the resulting composites were investigated by means of impedance spectroscopy. It was found that a very low critical weight fraction (pc = 0.064 wt %) which may be taken to correspond to the formation

Shalom Eliahou, Michel Kervaire, Cédric Lecouvey

Let $K \subset L$ be a commutative field extension. Given $K$-subspaces $A,B$ of $L$, we consider the subspace $<AB>$ spanned by the product set $AB=\{ab \mid a \in A, b \in B\}$. If $\dim_K A = r$ and $\dim_K B = s$, how small can the dimension of $<AB>$ be? In this paper we give a complete answer to this question in characteristic 0, and more generally for

Saharon Shelah, Shimon Garti

We prove a Theorem about the relationship between the Depth of the ultraproduct of Boolean algebras, divided by an ultrafilter, and the products of the depths of each component. This answers (partly) an open problem of Monk.

D. Parker, V. Dupuis, F. Ladieu, J. -P. Bouchaud

In this paper we investigate the superspin glass behavior of a concentrated assembly of interacting maghemite nanoparticles and compare it to that of canonical atomic spin glass systems. ac versus temperature and frequency measurements show evidence of a superspin glass transition taking place at low temperature. In order to fully characterize the superspin

Manon Defosseux

We study some random interlaced configurations considering the eigenvalues of the main minors of Hermitian random matrices of the classical complex Lie algebras. We claim that these random configurations are determinantal and give their correlation kernels.

S. Britzen, R. C. Vermeulen, G. B. Taylor, R. M. Campbell

Context: This is the first of a series of papers presenting VLBI observations of the 293 Caltech-Jodrell Bank Flat-Spectrum (hereafter CJF) sources and their analysis. Aims: One of the major goals of the CJF is to make a statistical study of the apparent velocities of the sources. Methods: We have conducted global VLBI and VLBA observations at 5 GHz since 19

Vladimir Lapshin

The method of constructing of Grothendieck&#39;s topology basing on a neighbourhood grammar, defined on the category of syntax diagrams is described in the article. Syntax diagrams of a formal language are the multigraphs with nodes, signed by symbols of the language&#39;s alphabet. The neighbourhood grammar allows to select correct syntax diagrams from the

Al Mokhtar Lamsabhi, Otilia Mó, Manuel Yáñez, Jean-Claude Guillemin

The gas-phase reactions between Ni+ (2D5/2) and aminoacetonitrile, a molecule of prebiological interest as possible precursor of glycine, have been investigated by means of mass spectrometry techniques. The mass-analyzed ion kinetic energy (MIKE) spectrum reveals that the adduct ions [NCCH2NH2, Ni+] spontaneously decompose by loosing HCN, H2, and H2CNH, the

J. L. Zhang, L. N. Wang, J. G. Jiang, L. L. Zhang

The string relaxation equation (SRE) of the string model for the glass transition contains the well-known Debye and Rouse-Zimm relaxation equations. However, its initial condition, necessary to the model predictions of glassy dynamics, such as the mechanism of the universal primary alpha- and Johari-Goldstein beta-relaxations in glassformers, has not been so

Yvonne C. Unruh, Natalie A. Krivova, Sami K. Solanki, Jerald W. Harder

Aims: We test the reliability of the observed and calculated spectral irradiance variations between 200 and 1600 nm over a time span of three solar rotations in 2004. Methods: We compare our model calculations to spectral irradiance observations taken with SORCE/SIM, SoHO/VIRGO and UARS/SUSIM. The calculations assume LTE and are based on the SATIRE (Spectral

Giuseppe Maiella

I will present a short review of recent achievements in understanding the origin of the statistical properties versus the thermodynamical ones for Anti De Sitter space--time, ADS$_{n+1}$ from the point of view of the &#34;dual&#34; field theory defined on the boundary of ADS$_{n+1}$ conformal invariant, CFT$_n$. We try to convince the audience that the symme

Ch. Blomers, Th. Schapers, T. Richter, R. Calarco

We report on low-temperature magnetotransport measurements on InN nanowires, grown by plasma-assisted molecular beam epitaxy. The characteristic fluctuation pattern observed in the conductance was employed to obtain information on phase-coherent transport. By analyzing the root-mean-square and the correlation field of the conductance fluctuations at various

Eunan J. McEniry, Thomas Frederiksen, Tchavdar N. Todorov, Daniel Dundas

A dynamical method for inelastic transport simulations in nanostructures is compared with a steady-state method based on non-equilibrium Green&#39;s functions. A simplified form of the dynamical method produces, in the steady state in the weak-coupling limit, effective self-energies analogous to those in the Born Approximation due to electron-phonon coupling

Ambar Jain, Ignazio Scimemi, Iain W. Stewart

Far above threshold the production process e^+e^-to t t-bar can be analyzed using effective field theories. In this talk we consider the invariant mass distribution of top-jets and report about our computation of the two-loop heavy quark jet-function. This is a key part of a next-to-next-to-leading order analysis, and already allows for a resummation of all

Antonio D&#39;Arrigo, Elena De Leo, Giuliano Benenti, Giuseppe Falci

We study a dephasing channel with memory, modelled by a Markov chain. We show that even weak memory effects have a detrimental impact on the performance of quantum error correcting schemes designed for uncorrelated errors. We also discuss an alternative scheme that takes advantage of memory effects to protect quantum information.

Marcel Ausloos, Mircea Gligor

The Cluster Variation Method known in statistical mechanics and condensed matter is revived for weighted bipartite networks. The decomposition of a Hamiltonian through a finite number of components, whence serving to define variable clusters, is recalled. As an illustration the network built from data representing correlations between (4) macro-economic feat

Thibault Damour, Marc Lilley

The aim of these lectures is to give an introduction to several topics which lie at the intersection of string theory, gravity theory and gravity phenomenology. One successively reviews: (i) the &#34;membrane&#34; approach to the dissipative dynamics of classical black holes, (ii) the current experimental tests of gravity, and their theoretical interpretatio

Ignacio Negueruela, J. Simon Clark, Paul A. Crowther, Lucy Hadfield

With a dynamical mass M_dyn ~ 1.3x10e5 M_sun and a lower limit M_cl>5x10e4 M_sun from star counts, Westerlund 1 is the most massive young open cluster known in the Galaxy and thus the perfect laboratory to study massive star evolution. We have developed a comprehensive spectral classification scheme for supergiants based on features in the 6000-9000A range,

Geza Kovacs

With the aid of stellar atmosphere models, we derive iron abundances [Fe/H] from the OGLE B, V, I photometry on the Magellanic Cloud Cepheids. We show that in both clouds the average metallicities of the first overtone variables are lower than those of the fundamental ones (by ~0.2 and ~0.3 dex in the LMC and SMC, respectively). Consequently, there is a corr

J. B. Satinover, D. Sornette

In the Minority, Majority and Dollar Games (MG, MAJG, $G), synthetic agents compete for rewards, at each time-step acting in accord with the previously best-performing of their limited sets of strategies. Different components and/or aspects of real-world financial markets are modelled by these games. In the MG, agents compete for scarce resources; in the MAJ

L. Lahoche, I. Luk&#39;yanchuk, G. Pascoli

Bounded charges induced by the polarization gradient in finite-size ferroelectrics are known to produce the unfavorable depolarization electric field that suppresses the uniform ferroelectric state. To reduce the depolarization energy the non-uniform vortex (toroidal) state is formed inside ferroelectric nano-particles, nano-disks, and nano-rods. Based on se

Urmas Haud

Traditionally IVC and HVC were defined to be concentrations of HI gas, with line-of-sight velocities that are inconsistent with data on the differential rotation of the Galaxy. We demonstrate that IVCs and HVCs can be identified from certain density enhancements in (V_C, FWHM) distribution of Gaussians, representing the Galactic HI 21 cm radio lines. We stud

A. Boccaletti, G. Chauvin, P. Baudoz, J. -L. Beuzit

Observations of low-mass companions for which the dynamical masses are well constrained help to improve the calibration of evolutionary models. Such observations thereby provide more confidence in the estimation of the mass of a companion using the photometric methods expected for the next generation of planet finder instruments. The commissioning of a new c

Kazuo Fujikawa

All the geometric phases are shown to be topologically trivial by using the second quantized formulation. The exact hidden local symmetry in the Schrödinger equation, which was hitherto unrecognized, controls the holonomy associated with both of the adiabatic and non-adiabatic geometric phases. The second quantized formulation is located in between the first

Iasson Karafyllis

In the present work, sufficient conditions for global stabilization of nonlinear uncertain systems by means of discrete-delay static output feedback are presented. Illustrating examples show the efficiency of the proposed control strategy.

Bruno Leibundgut

The extreme luminosity and their fairly unique temporal behaviour have made supernovae a superb tool to measure distances in the universe. As complex astrophysical events they provide interesting insights into explosion physics, explosive nucleosynthesis, hydrodynamics of the explosion and radiation transport. They are an end product of stellar evolution and

S. Vokal, A. D. Kovalenko, A. M. Kondratenko, M. A. Kondratenko

The physical spin program at high $p_T$ region and energies $s^{1/2}_{NN} \sim 10 GeV$ is discussed. It&#39;s shown that cumulative processes, color transparency problem and polarization phenomenons directly connect with properties new form of the nuclear matter as Color Quark Condensate(CQC). Studies of CQC one of the most important physical problem and can

T. Alonso-Albi, A. Fuente, R. Bachiller, R. Neri

We have carried out observations at millimeter and centimeter wavelengths towards VV Ser using the Plateau de Bure Interferometer and the Very Large Array. This allows us to compute the SED from near infrared to centimeter wavelengths. The modeling of the full SED has provided insight into the dust properties and a more accurate value of the disk mass. The m

S. Nehls, A. Hakenjos, M. J. Arts, J. Bluemer

Radio pulses are emitted during the development of air showers, where air showers are generated by ultra-high energy cosmic rays entering the Earth&#39;s atmosphere. These nanosecond short pulses are presently investigated by various experiments for the purpose of using them as a new detection technique for cosmic particles. For an array of 30 digital radio

I. Ya. Korenblit

We studied the effect of strong electric current on spin waves interacting relativistically with the current. The spin-wave spectrum is calculated at arbitrary direction of the wave vector. It is shown that the alternating Hall current generated by the alternating magnetic moment of the spin waves, reduces the spin-wave damping. At strong enough unpolarized

Satoko Sawada-Satoh, Seiji Kameno, Kayoko Nakamura, Daichi Namikawa

We present multi-frequency simultaneous VLBA observations at 15, 22 and 43 GHz towards the nucleus of the nearby radio galaxy NGC 1052. These three continuum images reveal a double-sided jet structure, whose relative intensity ratios imply that the jet axis is oriented close to the sky plane. The steeply rising spectra at 15-43 GHz at the inner edges of the

S. Britzen, R. C. Vermeulen, R. M. Campbell, G. B. Taylor

Context: This is the second of a series of papers presenting VLBI observations of the 293 Caltech-Jodrell Bank Flat-Spectrum (hereafter CJF) sources and their analysis. Aims: To obtain a consistent motion dataset large enough to allow the systematic properties of the population to be studied. Methods: We present the detailed kinematic analysis of the complet

Y. N Huang, J. L. Zhang, L. L. Zhang, L. N. Wang

We presented that the relaxation of n coupling molecules in a molecular string exhibits n individual relaxation modes (RMs), each mode being characterized by a definite relaxation time and amplitude according to the string model. The n RMs behaving a single relaxation at high temperature, evolves to two relaxation species, at low temperature, with different

Spyridon Kitsionas, Anthony P. Whitworth, Ralf S. Klessen

We present results of hydrodynamic simulations of star formation triggered by cloud-cloud collisions. During the early stages of star formation, low-mass objects form by gravitational instabilities in protostellar discs. A number of these low-mass objects are in the sub-stellar mass range, including a few objects of planetary mass. The disc instabilities tha

Juan A. Valiente Kroon

It is shown how the gauge of the ``regular finite initial value problem at spacelike infinity&#39;&#39; can be used to construct a certain type of estimates for the Maxwell field propagating on a Schwarzschild background. These estimates are constructed with the objective of obtaining information about the smoothness near spacelike and null infinity of a wid

MirFaez Miri, Ramin Golestanian

The coupling between corrugated surfaces due to the lateral Casimir force is employed to propose a nanoscale mechanical device composed of two racks and a pinion. The noncontact nature of the interaction allows for the system to be made frustrated by choosing the two racks to move in the same direction and forcing the pinion to choose between two opposite di

M. Asorey, P. Facchi, V. I. Man&#39;ko, G. Marmo

We introduce several possible generalizations of tomography for quadratic surfaces. We analyze different types of elliptic, hyperbolic and hybrid tomograms. In all cases it is possible to consistently define the inverse tomographic map. We find two different ways of introducing tomographic sections. The first method operates by deformations of the standard R

Santabrata Das, Indranil Chattopadhyay

Rotating accretion flow may undergo centrifugal pressure mediated shock transition even in presence of various dissipative processes, such as viscosity and cooling mechanism. The extra thermal gradient force along the vertical direction in the post shock flow drives a part of the accreting matter as bipolar outflows which are believed to be the precursor of

Catherine Quilliet, Shirin Ataei Talebi, David Rabaud, Jos Kaefer

A 2D foam can be characterised by its distribution of bubble areas, and of number of sides. Both distributions have an average and a width (standard deviation). There are therefore at least two very different ways to characterise the disorder. The former is a geometrical measurement, while the latter is purely topological. We discuss the common points and di

Sergey V. Golovin

Partially invariant solution to (2+1)D shallow water equation is constructed and investigated. The solution describes an extension of a stripe, bounded by linear source and drain of fluid. Realizations of smooth flow and of hydraulic jump are possible. Particle trajectories and sonic characteristics on the obtained solution are calculated.

Chi-Hang Lam, M. T. Lung, Leonard M. Sander

Accelerated algorithms for simulating the morphological evolution of strained heteroeptiaxy based on a ball and spring lattice model in three dimensions are explained. We derive exact Green&#39;s function formalisms for boundary values in the associated lattice elasticity problems. The computational efficiency is further enhanced by using a superparticle sur

Jun-ichi Nakashima, Shuji Deguchi, Hiroshi Imai, Athol Kemball

IRAS 19312+1950 is a unique SiO maser source, exhibiting a rich set of molecular radio lines, although SiO maser sources are usually identified as oxygen-rich evolved stars, in which chemistry is relatively simple comparing with carbon-rich environments. The rich chemistry of IRAS 19312+1950 has raised a problem in circumstellar chemistry if this object is r

Birendra Kumar Nayak, Sudhakar Sahoo

In this paper an algorithm is designed which generates in-equivalent Boolean functions of any number of variables from the four Boolean functions of single variable. The grammar for such set of Boolean function is provided. The Turing Machine that accepts such set is constructed.

Zhi Quan, Shuguang Cui, Ali H. Sayed, H. Vincent Poor

Spectrum sensing is an essential enabling functionality for cognitive radio networks to detect spectrum holes and opportunistically use the under-utilized frequency bands without causing harmful interference to legacy networks. This paper introduces a novel wideband spectrum sensing technique, called multiband joint detection, which jointly detects the signa

Jarrod R. Hurley, Michael M. Shara, Harvey B. Richer, Ivan R. King

We present N-body models to complement deep imaging of the metal-poor core-collapsed cluster NGC6397 obtained with the Hubble Space Telescope. All simulations include stellar and binary evolution in-step with the stellar dynamics and account for the tidal field of the Galaxy. We focus on the results of a simulation that began with 100000 objects (stars and b

Peter Andru, Alexei Botchkarev

Ontario (Canada) Health System stakeholders support the idea and necessity of the integrated source of data that would include both clinical (e.g. diagnosis, intervention, length of stay, case mix group) and financial (e.g. cost per weighted case, cost per diem) characteristics of the Ontario healthcare system activities at the patient-specific level. At pre

Jakob Stix

Period and index of a curve $X/K$ over a $p$-adic local field $K$ such that the fundamental group $π_1(X/K)$ admits a splitting are shown to be powers of $p$. As a consequence, examples of curves over number fields are constructed where having sections is obstructed locally at a $p$-adic place. Hence the section conjecture holds for these curves as there are

Tohru Nagao, Shunji Sasaki, Roberto Maiolino, Celestine Grady

We present a new photometric search for high-z galaxies hosting Population III (PopIII) stars based on deep intermediate-band imaging observations obtained in the Subaru Deep Field (SDF), by using Suprime-Cam on the Subaru Telescope. By combining our new data with the existing broad-band and narrow-band data, we searched for galaxies which emit strongly both

Robert J Taggart

We present abstract inhomogeneous Strichartz estimates for dispersive operators, extending previous work by M. Keel and T. Tao on the one hand, and generalising results of D. Foschi, M. Vilela, M. Nakamura and T. Ozawa on the other hand. It is shown that these abstract estimates imply new inhomogeneous Strichartz estimates for the wave equation and some Schr

James T. Radomski, Christopher Packham, N. A. Levenson, Eric Perlman

We present high spatial resolution mid-IR images of the nuclear region of NGC 5128 (Centaurus A). Images were obtained at 8.8 micron, N-band (10.4 micron), and 18.3 micron using the mid-IR imager/spectrometer T-ReCS on Gemini South. These images show a bright unresolved core surrounded by low-level extended emission. We place an upper limit to the size of th

Keisuke Goda, Osamu Miyakawa, Eugeniy E. Mikhailov, Shailendhar Saraf

The quantum nature of the electromagnetic field imposes a fundamental limit on the sensitivity of optical precision measurements such as spectroscopy, microscopy, and interferometry. The so-called quantum limit is set by the zero-point fluctuations of the electromagnetic field, which constrain the precision with which optical signals can be measured. In the

Pritiraj Mohanty

Quantum Nanomechanics is the emerging field which pertains to the mechanical behavior of nanoscale systems in the quantum domain. Unlike the conventional studies of vibration of molecules and phonons in solids, quantum nanomechanics is defined as the quantum behavior of the entire mechanical structure, including all of its constituents--the atoms, the molecu

Björn Engquist, Lexing Ying

This paper introduces a directional multiscale algorithm for the two dimensional $N$-body problem of the Helmholtz kernel with applications to high frequency scattering. The algorithm follows the approach in [Engquist and Ying, SIAM Journal on Scientific Computing, 29 (4), 2007] where the three dimensional case was studied. The main observation is that, for

Shesha Raghunathan, Todd Brun

A new engineering technique using continuous quantum measurement in conjunction with feed-forward is proposed to improve indistinguishability of a single-photon source. The technique involves continuous monitoring of the state of the emitter, processing the noisy output signal with a simple linear estimation algorithm, and feed forward to control a variable

Guo-meng Zhao, John Mann

We report magnetic susceptibility $χ(T)$ measurements on oxygen-isotope exchanged La$_{1-x}$Ca$_{x}$MnO$_{3+y}$ up to 700 K. The $1/χ(T)$ data show that the ferromagnetic exchange-energy $J$ depends strongly on the oxygen-isotope mass. The isotope effect on $J$ decreases with temperature up to 400 K and then increases again with temperature above 400 K. This

Hanna E. Makaruk, Robert Owczarek

Natural languages are described in this paper in terms of networks of synonyms: a word is identified with a node, and synonyms are connected by undirected links. Our statistical analysis of the network of synonyms in Polish language showed it is scale-free; similar to what is known for English. The statistical properties of the networks are also similar. Thu

N. Pinto-Neto, F. P. Poulis, J. M. Salim

We investigate if theories yielding bouncing cosmological models also generate wormhole solutions. We show that two of them present sensible traversable static wormhole solutions, while for the third possibility such solutions are absent.

John Mann, Pieder Beeli, Guo-meng Zhao

We have studied the oxygen-isotope effect on the superconducting transition temperature $T_{c}$ in overdoped Y$_{1-x}$Ca$_{x}$Ba$_{2}$Cu$_{3}$O$_{7-δ}$ with $x$ = 0.10, 0.20, and 0.25. We find the oxygen-isotope exponent $α_{O}$ to be small ($\sim$0.02) for $x$ = 0.10 but substantial ($\sim$0.1) for $x$ = 0.20 and 0.25. The doping level above which $α_{O}$ i

L. G. Gerchikov, G. F. Gribakin

We study the process of low-energy electron capture by the SF6 molecule. Our approach is based on the model of Gauyacq and Herzenberg [J. Phys. B 17, 1155 (1984)] in which the electron motion is coupled to the fully symmetric vibrational mode through a weakly bound or virtual s state. By tuning the two free parameters of the model, we achieve an accurate des

Jaroslav Albert, E. M. Chudnovsky

Mechanical stress causes motion of defects in solids. We show that in a type-II superconductor a moving dislocation generates a pattern of current that exerts the depinning force on the surrounding vortex lattice. Concentration of dislocations and the mechanical stress needed to produce critical depinning currents are shown to be within practical range. When

Cheng-Yu Kuo, Jeremy Lim, Ya-Wen Tang, Paul T. P. Ho

No mechanisms have hitherto been conclusively demonstrated to be responsible for initiating optically-luminous nuclear (Seyfert) activity in local disk galaxies. Only a small minority of such galaxies are visibly disturbed in optical starlight, with the observed disturbances being at best marginally stronger than those found in matched samples of inactive ga

Michael Wilkinson, Bernhard Mehlig

After reviewing the difficulties faced by the conventional theory of planet formation (based upon the aggregation of microscopic dust particles), we describe an alternative hypothesis. We propose that planets form by gravitational collapse at the same time as the star about which they orbit. This &#39;concurrent collapse&#39; hypothesis avoids theoretical di

David Blanc, Mark W. Johnson, James M. Turner

The aim of this paper is to construct and examine three candidates for local-to-global spectral sequences for the cohomology of diagrams of algebras with directed indexing. In each case, the $E^2$ -terms can be viewed as a type of local cohomology relative to a map or an object in the diagram.

Ryan M. Wilson, Shai Ronen, Han Pu, John L. Bohn

We investigate the structure of trapped Bose-Einstein condensates (BECs) with long-range anisotropic dipolar interactions. We find that a small perturbation in the trapping potential can lead to dramatic changes in the condensate&#39;s density profile for sufficiently large dipolar interaction strengths and trap aspect ratios. By employing perturbation theor

Gary W. Gibbons, Steffen Gielen

The Petrov solution (for $Λ=0$) and the Kaigorodov-Ozsváth solution (for $Λ<0$) provide examples of vacuum solutions of the Einstein equations with simply-transitive isometry groups. We calculate the boundary stress-tensor for the Kaigorodov-Ozsváth solution in the context of the adS/CFT correspondence. By giving a matrix representation of the Killing algebr

Soumen Mandal, R. C. Budhani

The isothermal magnetoresistance [R($θ$)] of [001] and [110] epitaxial films of La$_{2 / 3}$Sr$_{1 / 3}$MnO$_{3}$ measured as a function of the angle $θ$ between current ($\vec{I}$) and magnetic field ($\vec{H}$), both in the plane of the film, is measured at several temperatures between 10 and 300K. The magnetic easy axis of these polytypes is intimately re

Genya Takeda, Ryosuke Kita, Frederic A. Rasio

Many recent observational studies have concluded that planetary systems commonly exist in multiple-star systems. At least ~20% of the known extrasolar planetary systems are associated with one or more stellar companions. The orbits of stellar binaries hosting planetary systems are typically wider than 100 AU and often highly inclined with respect to the plan

Marco Cavaglia, Benjamin Harms

In this paper we discuss a method of generating supersymmetric solutions of the Einstein equations. The method involves the embedding of one supersymmetric spacetime into another. We present two examples with constituent spacetimes which support &#34;charges&#34;, one of which was known previously and the other of which is new. Both examples have PP-waves as

Alistair Savage

Henriques and Kamnitzer have defined a commutor for the category of crystals of a finite-dimensional complex reductive Lie algebra that gives it the structure of a coboundary category (somewhat analogous to a braided monoidal category). Kamnitzer and Tingley then gave an alternative definition of the crystal commutor, using Kashiwara&#39;s involution on Verm

Eric Greenwood, Dejan Stojkovic

We investigate gravitational collapse in the context of quantum mechanics. We take primary interest in the behavior of the collapse near the horizon and near the origin (classical singularity) from the point of view of an infalling observer. In the absence of radiation, quantum effects near the horizon do not change the classical conclusions for an infalling

Martin H. Weissman

Smooth irreducible representations of tori over local fields have been parameterized by Langlands, using class field theory and Galois cohomology. This paper extends this parameterization to central extensions of such tori, which arise naturally in the setting of nonlinear covers of reductive groups.

P. Kotetes, G. Varelogiannis

We study the electromagnetic response of a chiral ${\rm d_{xy}+id_{x^2-y^2}}$ charge density wave state. Due to parity (${\cal P}$) and time reversal (${\cal T}$) violation, Chern-Simons terms emerge in the effective action of the U(1) gauge field. As a consequence electric and magnetic fields are coupled providing the possibility of observing the Spontaneou

Eugen Paal

Triple closure of the infinitesimal translations of an analytic Moufang loop is inquired. This property is equivalent to reductivity and relates Mal&#39;tsev algebras to the Lie triple systems.

Ivan Agullo, J. Fernando Barbero G., Jacobo Diaz-Polo, Enrique Fernandez-Borja

We give a practical method to exactly compute black hole entropy in the framework of Loop Quantum Gravity. Along the way we provide a complete characterization of the relevant sector of the spectrum of the area operator, including degeneracies, and determine the number of solutions to the projection constraint analytically. We use a computer implementation o