April 2009 arXiv papers — page 18

Majid Fozunbal

We consider the problem of recognizing a vocabulary--a collection of words (sequences) over a finite alphabet--from a potential subsequence of one of its words. We assume the given subsequence is received through a deletion channel as a result of transmission of a random word from one of the two generic underlying vocabularies. An exact maximum a posterior (

Henry Crapo

We sketch the outlines of Gian Carlo Rota's interaction with the ideas that Hermann Grassmann developed in his Ausdehnungslehre of 1844 and 1862, as adapted and explained by Giuseppe Peano in 1888. This leads us past what Rota variously called 'Grassmann-Cayley algebra', or 'Peano spaces', to the Whitney algebra of a matroid, and finally

M. Vestergaard, Patrick S. Osmer

We present mass functions of distant actively accreting supermassive black holes residing in luminous quasars discovered in the Large Bright Quasar Survey, the Bright Quasar Survey, and the Fall Equatorial Stripe of the Sloan Digital Sky Survey (SDSS). The quasars cover a wide range of redshifts (0 <~ z <= 5) and were subject to different selection criteria

Gabriella De Lucia

In the past decades, different approaches have been developed in order to link the physical properties of galaxies to the dark matter haloes in which they reside. In this review, I give a brief overview of methods, aims, and limits of these techniques, with particular emphasis on semi-analytic models of galaxy formation. For these models, I also provide a br

Leanne D. Duffy, Karl van Bibber

We review the current status of axions as dark matter. Motivation, models, constraints and experimental searches are outlined. The axion remains an excellent candidate for the dark matter and future experiments, particularly the Axion Dark Matter eXperiment (ADMX), will cover a large fraction of the axion parameter space.

T. Nguyen, N. A. Souchlas, P. C. Tandy

Using a ladder-rainbow kernel previously established for light quark hadron physics, we explore the extension to masses and electroweak decay constants of ground state pseudoscalar and vector quarkonia and heavy-light mesons in the c- and b-quark regions. We make a systematic study of the effectiveness of a constituent mass concept as a replacement for a hea

Leonid Bedratyuk

Let $\mathcal{I}_{d_1,d_2}$ and $\mathcal{C}_{d_1,d_2}$ be the algebras of joint invariants and joint covariants of the two binary forms of degrees $d_1$ and $d_2.$ Formulas for computation of the Poincaré series $\mathcal{PI}_{d_1,d_2}(z),$ $ \mathcal{PC}_{d_1,d_2}(z)$ of the algebras is found. By using these formulas, we have computed the series for $d_1,d

Christophe Gissinger, Emmanuel Dormy, Stephan Fauve

We present direct numerical simulations of reversals of the magnetic field generated by swirling flows in a spherical domain. In agreement with a recent model, we observe that coupling dipolar and quadrupolar magnetic modes by an asymmetric forcing of the flow generates field reversals. In addition, we show that this mechanism strongly depends on the value o

Fabiana Faustini, Sergio Molinari, Leonardo Testi, Jan Brand

[Abridged] Twenty-six high-luminosity IRAS sources believed to be collection of stars in the early phases of high-mass star formation have been observed in the NIR (J, H, K) to characterize the clustering properties of their young stellar population and gain insight into the initial conditions of star formation in these clusters (Initial Mass Function [IMF],

Chris Gioran, Ioannis Kontoyiannis

The compression-complexity trade-off of lossy compression algorithms that are based on a random codebook or a random database is examined. Motivated, in part, by recent results of Gupta-Verdú-Weissman (GVW) and their underlying connections with the pattern-matching scheme of Kontoyiannis&#39; lossy Lempel-Ziv algorithm, we introduce a non-universal version o

Feng-Kun Guo, Christoph Hanhart, Ulf-G. Meißner

In recent years, many heavy mesons and charmonia were observed which do not fit in the conventional quark model expectations. Some of them are proposed to be hadronic molecules. Here we investigate the consequences of heavy quark spin symmetry on these heavy meson hadronic molecules. Heavy quark spin symmetry enables us to predict new heavy meson molecules a

Merlin C. Davies, Luc Marleau

We study various properties of a one parameter mass term for the Skyrme model, originating from the works of Kopeliovich, Piette and Zakrzewski, through the use of axially symmetric solutions obtained numerically by simulated-annealing. These solutions allow us to observe asymptotic behaviors of the B=2 binding energies that differ to those previously obtain

Althea V. Moorhead, Eric B. Ford

The observed extrasolar planets possess both large masses (with a median M sin i of 1.65 MJ) and a wide range in orbital eccentricity (0 < e < 0.94). As planets are thought to form in circumstellar disks, one important question in planet formation is determining whether, and to what degree, a gaseous disk affects an eccentric planet&#39;s orbit. Recent studi

Kim K. Nilsson, Klaus Meisenheimer, Nicholas Bond, Eric Gawiser

This publication contains the conference summary of the Understanding Lyman-alpha Emitters conference held at the Max Planck Institute for Astronomy in Heidelberg October 6 - 10, 2008. The scope of the conference was to bring together most of the scientists working in the field of Lyman-alpha emitters, whether at low or high redshift, or on observational or

Andrew P. Hearin, Andrew R. Zentner

Forthcoming projects such as the DES, a JDEM, and LSST, aim to measure weak lensing shear correlations with unprecedented accuracy. Weak lensing observables are sensitive to both the distance-redshift relation and the growth of structure in the Universe. If the cause of accelerated cosmic expansion is dark energy within general relativity (GR), both cosmic d

Sara L. Ellison, Sebastian Lopez

The Complete Optical and Radio Absorption Line System (CORALS) survey has previously been used to demonstrate that the number density, gas and metals content of z>1.6 damped Lyman alpha systems is not significantly under-estimated in magnitude limited surveys. In this paper, a sample of strong MgII absorbers selected from the optically complete 0.7 < z < 1.6

Changrim Ahn, Chanju Kim, Eric V. Linder

Cosmological constant behavior can be realized as solutions of the Dirac-Born-Infeld (DBI) action within Type IIB string theory and the AdS/CFT correspondence. We derive a family of attractor solutions to the cosmological constant that arise purely from the &#34;relativistic&#34; nature of the DBI action without an explicit false vacuum energy. We also find

Mario Pasquato, Michele Trenti, Guido De Marchi, Michael Gill

[abridged] Theoretical investigations have suggested the presence of Intermediate Mass Black Holes (IMBHs, with masses in the 100-10000 Msun range) in the cores of some Globular Clusters (GCs). In this paper we present the first application of a new technique to determine the presence or absence of a central IMBH in globular clusters that have reached energy

Shariq Bashir, Saad Razzaq, Umer Maqbool, Sonya Tahir

Handling missing values in training datasets for constructing learning models or extracting useful information is considered to be an important research task in data mining and knowledge discovery in databases. In recent years, lot of techniques are proposed for imputing missing values by considering attribute relationships with missing value observation and

Shariq Bashir, Saad Razzaq, Umer Maqbool, Sonya Tahir

The quality of training data for knowledge discovery in databases (KDD) and data mining depends upon many factors, but handling missing values is considered to be a crucial factor in overall data quality. Today real world datasets contains missing values due to human, operational error, hardware malfunctioning and many other factors. The quality of knowledge

Shariq Bashir, Zahoor Jan, Abdul Rauf Baig

Real world datasets are sparse, dirty and contain hundreds of items. In such situations, discovering interesting rules (results) using traditional frequent itemset mining approach by specifying a user defined input support threshold is not appropriate. Since without any domain knowledge, setting support threshold small or large can output nothing or a large

Shariq Bashir, Abdul Rauf Baig

Mining frequent itemset using bit-vector representation approach is very efficient for dense type datasets, but highly inefficient for sparse datasets due to lack of any efficient bit-vector projection technique. In this paper we present a novel efficient bit-vector projection technique, for sparse and dense datasets. To check the efficiency of our bit-vecto

Y. -J. Lin, A. R. Perry, R. L. Compton, I. B. Spielman

We describe an apparatus for quickly and simply producing $\Rb87$ Bose-Einstein condensates. It is based on a magnetic quadrupole trap and a red detuned optical dipole trap. We collect atoms in a magneto-optical trap (MOT) and then capture the atom in a magnetic quadrupole trap and force rf evaporation. We then transfer the resulting cold, dense cloud into a

Eric D&#39;Hoker, John Estes, Michael Gutperle, Darya Krym

We present a one-parameter deformation of the AdS_{4} x S^{7} vacuum, which is a regular solution in M-theory, invariant under SO(2,2) x SO(4) x SO(4), and which preserves 16 supersymmetries. The solution corresponds to a holographic realization of a Janus-like interface/defect theory, despite the absence of a dilaton in M-theory. The 2+1-dimensional CFT dua

Shariq Bashir, Abdul Rauf Baig

In this paper we present a novel hybrid (arraybased layout and vertical bitmap layout) database representation approach for mining complete Maximal Frequent Itemset (MFI) on sparse and large datasets. Our work is novel in terms of scalability, item search order and two horizontal and vertical projection techniques. We also present a maximal algorithm using t

Jens Kroeske

This thesis is concerned with the theory of invariant bilinear differential pairings on parabolic geometries. It introduces the concept formally with the help of the jet bundle formalism and provides a detailed analysis. More precisely, after introducing the most important notations and definitions, we first of all give an algebraic description for pairings

Shariq Bashir, Abdul Rauf Baig

Maximal frequent patterns superset checking plays an important role in the efficient mining of complete Maximal Frequent Itemsets (MFI) and maximal search space pruning. In this paper we present a new indexing approach, FastLMFI for local maximal frequent patterns (itemset) propagation and maximal patterns superset checking. Experimental results on different

I. Ispolatov, Michael Doebeli

We develop a model for speciation due to postzygotic incompatibility generated by autoimmune reactions. The model is based on predator-prey interactions between a host plants and their pathogens. Such interactions are often frequency-dependent, so that pathogen attack is focused on the most abundant plant phenotype, while rare plant types may escape pathogen

Chris Vuille, Jocelyn Dunn

The Klein-Gordon equations were recently solved in general relativity for the case of a plane-symmetric static massless scalar field with cosmological constant. By analytic continuation, time-dependent solutions can be obtained that correspond to cosmologies. These spacetimes are studied here, and include among them a solution exhibiting both early inflation

Bas Lemmens, Cormac Walsh

We show that the isometry group of a polyhedral Hilbert geometry coincides with its group of collineations (projectivities) if and only if the polyhedron is not an n-simplex with n>=2. Moreover, we determine the isometry group of the Hilbert geometry on the n-simplex, and find that it has the collineation group as an index-two subgroup. These results confirm

Paul C. Clark, Simon C. O. Glover, Ian A. Bonnell, Ralf S. Klessen

The observed slope at the high-mass end of the initial mass function (IMF) displays a remarkable universality in a wide variety of physical environments. We predict that competitive accretion, the ongoing accretion of gas from a common reservoir by a collection of protostellar cores, can provide a natural explanation for such a universal slope in star formin

Liviu I. Nicolaescu

We analyze a bead sliding game and relate it to some classical convex inequalities.

Zacky Choo, Victor Snaith

We derive a power series formula for the $p$-adic regulator on the higher dimensional algebraic K-groups of number fields. This formula is designed to be well suited to computer calculations and to reduction modulo powers of $p$. In addition we describe a series of regulator questions concerning higher dimensional K-theoretic analogues of conjectures of Gros

J. -L. Starck, J. M. Fadili, S. Digel, B. Zhang

The multiscale variance stabilization Transform (MSVST) has recently been proposed for Poisson data denoising. This procedure, which is nonparametric, is based on thresholding wavelet coefficients. We present in this paper an extension of the MSVST to 3D data (in fact 2D-1D data) when the third dimension is not a spatial dimension, but the wavelength, the en

Sergey P. Tarabrin, Sergey P. Vyatchanin

In this paper we demonstrate that a double Michelson interferometer with Fabry-Perot cavities in its arms is able to perform laser- and displacement-noise-free gravitational-wave (GW) detection if certain model assumptions are met. Assuming the input mirrors of a single Michelson/Fabry-Perot interferometer can be rigidly attached to beamsplitter on a central

Yannick Baraud

We use the generic chaining device proposed by Talagrand to establish exponential bounds on the deviation probability of some suprema of random processes. Then, given a random vector $ξ$ in $\R^{n}$ the components of which are independent and admit a suitable exponential moment, we deduce a deviation inequality for the squared Euclidean norm of the projectio

Thao Tran

F-polynomials and g-vectors were defined by Fomin and Zelevinsky to give a formula which expresses cluster variables in a cluster algebra in terms of the initial cluster data. A quantum cluster algebra is a certain noncommutative deformation of a cluster algebra. In this paper, we define and prove the existence of analogous quantum F-polynomials for quantum

Luca Martinazzi, Mircea Petrache

Given a regular bounded domain $\Omega\subset\R{2m}$, we describe the limiting behavior of sequences of solutions to the mean field equation of order $2m$, $m\geq 1$, $$(-\Delta)^m u=\rho \frac{e^{2mu}}{\int_\Omega e^{2mu}dx}\quad\text{in}\Omega,$$ under the Dirichlet boundary condition and the bound $0<\rho\leq C$. We emphasize the connection with the probl

Zhichun Zhai

Let $b_α^{p}(\mathbb{R}^{1+n}_{+})$ be the space of solutions to the parabolic equation $\partial_{t}u+(-\triangle)^αu=0$ $(α\in(0, 1])$ having finite $L^{p}(\mathbb{R}^{1+n}_{+})$ norm. We characterize nonnegative Radon measures $μ$ on $\mathbb{R}^{1+n}_{+}$ having the property $\|u\|_{L^{q}(\mathbb{R}^{1+n}_{+},μ)}\lesssim \|u\|_{\dot{W}^{1,p}(\mathbb{R}^{

M. Goldin, D. Francisco, S. Ledesma

We present here a classical optics device based on an imaging architecture as analogy of a quantum system where the violation of the Bell inequality can be evidenced. In our case, the two qbits entangled state needed to obtain non classical correlations is encoded using an electromagnetic wave modulated in amplitude and phase. Computational states are repres

Diogo A. Gomes, Nara Jung, Artur O. Lopes

In this paper we study minimax Aubry-Mather measures and its main properties. We consider first the discrete time problem and then the continuous time case. In the discrete time problem we establish existence, study some of the main properties using duality theory and present some examples. In the continuous time case, we establish both existence and non-exi

Li Shi, Jianhua Zhou, Philip Kim, Adrian Bachtold

The temperature distributions in current-carrying carbon nanotubes have been measured with a scanning thermal microscope. The obtained temperature profiles reveal diffusive and dissipative electron transport in multi-walled nanotubes and in single-walled nanotubes when the voltage bias was higher than the 0.1-0.2 eV optical phonon energy. Over ninety percent

Pengtao Li, Zhichun Zhai

In this paper, we establish a link between Leray mollified solutions of the three-dimensional generalized Naiver-Stokes equations and mild solutions for initial data in the adherence of the test functions for the norm of $Q^{β,-1}_{α, loc}(\mathbb{R}^{3}).$ This result applies to the usual incompressible Navier-Stokes equations and deduces a known link.

K. L. DeRose, T. L. Bourke, R. A. Gutermuth, S. J. Wolk

We present adaptive optics (AO) near-infrared (JHKs) observations of the deeply embedded massive cluster RCW 38 using NACO on the VLT. Narrowband AO observations centered at wavelengths of 1.28, 2.12, and 2.17 micron were also obtained. The area covered by these observations is about 0.5 pc square, centered on the O star RCW 38 IRS2. We use the JHKs colors t

Andreas Cap, Josef Silhan

We construct an explicit scheme to associate to any potential symbol an operator acting between sections of natural bundles (associated to irreducible representations) for a so-called AHS-structure. Outside of a finite set of critical (or resonant) weights, this procedure gives rise to a quantization, which is intrinsic to this geometric structure. In partic

S. V. Borisenko, A. A. Kordyuk, V. B. Zabolotnyy, D. S. Inosov

Using angle-resolved photoemission spectroscopy (ARPES), we report on the direct observation of the energy gap in 2H-NbSe2 caused by the charge-density waves (CDW). The gap opens in the regions of the momentum space connected by the CDW vectors, which implies a nesting mechanism of CDW formation. In remarkable analogy with the pseudogap in cuprates, the dete

S. I. Eidelman

The current status of the Standard Model predictions for the muon anomalous magnetic moment is described. Various contributions expected in the Standard Model are discussed. After the reevaluation of the leading-order hadronic term based on the new \ep data, the theoretical prediction is more than three standard deviations lower than the experimental value.

Pengtao Li, Zhichun Zhai

We study the well-posedness and regularity of the generalized Navier-Stokes equations with initial data in a new critical space $Q_{α;\infty}^{β,-1}(\mathbb{R}^{n})=\nabla\cdot(Q_α^β(\mathbb{R}^{n}))^{n}, β\in({1/2},1)$ which is larger than some known critical homogeneous Besov spaces. Here $Q_α^β(\mathbb{R}^{n})$ is a space defined as the set of all measura

V. A. Cherepanov, S. I. Eidelman

We use experimental data on $e^+e^- \to η(η^{\prime})π^+π^-$ and conservation of vector current to estimate the branching fractions of $τ^-$ decay to $η(η^{\prime})π^-π^0ν_τ$. The obtained values are compared to the experimental results.

Søren K. Boldsen

In this paper we prove stability results for the homology of the mapping class group of a surface. We get a stability range that is near optimal, and extend the result to twisted coefficients.

Gil Kalai

In this paper we consider adversarial noise models that will fail quantum error correction and fault-tolerant quantum computation. We describe known results regarding high-rate noise, sequential computation, and reversible noisy computation. We continue by discussing highly correlated noise and the &#34;boundary,&#34; in terms of correlation of errors, of th

Gerasim Kokarev

We study a variational problem for the first Schrodinger eigenvalue on closed Riemannian surfaces. More precisely, we explore concentration-compactness properties of sequences formed by its extremal potentials.

E. Minguzzi

It is proved that in a distinguishing spacetime the horismos relation E^+=J^+\I^+ generates the causal relation J^+. In other words two causally related events are joined by a chain of horismotically related events, or again, the causal relation is the smallest transitive relation containing the horismos relation. The result is sharp in the sense that distin

Marco S. Bianchi, Silvia Penati, Alberto Romagnoni, Massimo Siani

Renormalizable nonanticommutative SYM theories with chiral matter in the adjoint representation of the gauge group have been recently constructed in [arXiv:0901.3094]. In the present paper we focus on the U*(1) case with matter interacting through a cubic superpotential. For a single flavor, in a superspace setup and manifest background covariant approach we

Zhichun Zhai

We obtain Strichartz estimates for the fractional heat equations by using both the abstract Strichartz estimates of Keel-Tao and the Hardy-Littlewood-Sobolev inequality. We also prove an endpoint homogeneous Strichartz estimate via replacing $ L^{\infty}_{x}(\mathbb{R}^{n})$ by $BMO_{x}(\mathbb{R}^{n})$ and a parabolic homogeneous Strichartz estimate. Meanwh

F. Annibali, M. Tosi, M. Monelli, M. Sirianni

(Abridged). We present HST photometry of the late-type dwarf galaxy NGC 1705 observed with the WFPC2 in the U and B bands, and with the ACS/HRC in the U, V, and I bands. We cross-correlate these data with previous ones acquired with the WFPC2 in V and I and derive multiband Color-Magnitude diagrams (CMDs) of the cross-identified individual stars and candidat

B. Toen, G. Vezzosi

This is a companion paper our previous submission &#34;\infty-categories monoidales rigides et caracteres de Chern&#34;, in which we give a comparison between functions on the derived loop space of a smooth scheme of caracteristic zero, and its algebraic de Rham cohomology. As a consequence we obtain functorial and multiplicative versions of the HKR decompos

S. F. King

In this talk we survey some of the recent promising developments in the search for the theory behind neutrino mass and mixing, and indeed all fermion masses and mixing. The talk is organized in terms of a neutrino mass models decision tree according to which the answers to experimental questions provide sign posts to guide us through the maze of theoretical

Yves Jouanneau, Christine Meyer, Jean Jakoncic, V. Stojanoff

In Sphingomonas CHY-1, a single ring-hydroxylating dioxygenase is responsible for the initial attack of a range of polycyclic aromatic hydrocarbons (PAHs) composed of up to five rings. The components of this enzyme were separately purified and characterized. The oxygenase component (ht-PhnI) was shown to contain one Rieske-type [2Fe-2S] cluster and one monon

Andreas Björklund, Thore Husfeldt, Petteri Kaski, Mikko Koivisto

We study the time and space complexity of matrix permanents over rings and semirings.

Simon N. M. Ruijsenaars

The Heun equation can be rewritten as an eigenvalue equation for an ordinary differential operator of the form $-d^2/dx^2+V(g;x)$, where the potential is an elliptic function depending on a coupling vector $g\in{\mathbb R}^4$. Alternatively, this operator arises from the $BC_1$ specialization of the $BC_N$ elliptic nonrelativistic Calogero-Moser system (a.k.

Youssef El-Khatib

We compute Greeks for stochastic volatility models driven by Brownian informations. We use the Malliavin method introduced for deterministic volatility models.

Alberto Aparici, Kyungwook Kim, Arcadi Santamaria, Jose Wudka

We discuss the phenomenology of the most general effective Lagrangian, up to operators of dimension 5, build with standard model fields and interactions including right-handed neutrinos. In particular we find there is a dimension 5 electroweak moment operator of right-handed neutrinos, not discussed previously in the literature, which could have interesting

Manuel Oriol

The music industry has huge troubles adapting to the new technologies. As many pointed out, when copying music is essentially free and socially accepted it becomes increasingly tempting for users to infringe copyrights and copy music from one person to another. The answer of the music industry is to outlaw a majority of citizens. This article describes how t

Alexey Boyarsky, Vadim Cheianov, Jürg Fröhlich

We present a list of possible effective theories which may describe a QHE edge at filling fraction $ν=5/2$. We show that there exist several abelian and non-abelian effective theories (apart from those discussed in the literature) compatible with the physical requirements imposed by the microscopic nature of the system. We compare predictions of these theori

Olaf Kittel

In the Minimal Supersymmetric Standard Model, physical phases of complex parameters lead to CP violation. We show how triple products of particle momenta or spins can be used to construct asymmetries, that allow us to probe these CP phases. To give specific examples, we discuss the production of neutralinos at the International Linear Collider. For the Large

Fabrizio Buscemi, Giuseppe Compagno

Quantum detection processes in QFT must play a key role in the description of quantum field correlations, such as the appearance of entanglement, and of causal effects. We consider the detection in the case of a simple QFT model with a suitable interaction to exact treatment, consisting of a quantum scalar field coupled linearly to a classical scalar source.

M. Orienti

It is currently accepted that compact and bright radio sources characterized by a convex spectrum peaking at frequencies ranging from 100 MHz to a few GHz are young objects. In this scenario, high frequency peaker (HFP) radio sources, with a turnover frequency higher than 5 GHz are good candidates to be extremely young radio sources with ages of up to a few

D. Mogilevtsev, T. Tyc, N. Korolkova

In this work we investigate an influence of decoherence effects on quantum states generated as a result of the cross-Kerr nonlinear interaction between two modes. For Markovian losses (both photon loss and dephasing), a region of parameters when losses still do not lead to destruction of non-classicality is identified. We emphasize the difference in impact o

Yun Liu, Jia Zhang

Nanoscale lithography on La$_{0.7}$Sr$_{0.3}$MnO$_{3}$ (LSMO) thin film surfaces has been performed by scanning tunneling microscopy under ambient conditions. From line-etching experiments we found that the line depth is increasing in a step-wise fashion with increasing bias voltage as well as with decreasing scan speed. On average, the depth of the etched l

Robert J. Buenker

The properties of light in the presence of electromagnetic and gravitational fields are compared. Once one takes account of the fact that clock rates vary with distance from a massive object, it is argued that in an absolute sense light frequencies remain constant in both interactions. It is also pointed out that the criterion used by Einstein for the angle

A M Stoneham

I propose that the need for sleep and the occurrence of dreams are intimately linked to the physical processes underlying the continuing replacement of cells and renewal of biomolecules during the lives of higher organisms. Since one major function of our brains is to enable us to react to attack, there must be truly compelling reasons for us to take them of

J. Pekala, P. Homola, B. Wilczynska, H. Wilczynski

Atmospheric scattering of light emitted by an air shower not only attenuates direct fluorescence light from the shower, but also contributes to the observed shower light. So far only direct and singly-scattered Cherenkov photons have been taken into account in routine analyses of the observed optical image of air showers. In this paper a Monte Carlo method o

R. L. Lovas, J. Szilasi

We give a new and complete proof of the following theorem, discovered by Detlef Laugwitz: (forward) complete and connected finite dimensional Finsler manifolds admitting a proper homothety are Minkowski vector spaces. More precisely, we show that under these hypotheses the Finsler manifold is isometric to the tangent Minkowski vector space of the fixed point

D. Salloch, U. Wieser, U. Kunze, T. Hackbarth

Injection-type ballistic rectifiers on Si/SiGe are studied with respect to the influence of gate voltage on the transfer resistance RT (output voltage divided by input current) for different positions of a local gate electrode. The rectifiers are trifurcated quantum wires with straight voltage stem and oblique current-injecting leads. Depending on the gate c

Bernhard Eckl, Jadran Vrabec, Hans Hasse

A parameterization strategy for molecular models on the basis of force fields is proposed, which allows a rapid development of models for small molecules by using results from quantum mechanical (QM) ab initio calculations and thermodynamic data. The geometry of the molecular models is specified according to the atom positions determined by QM energy minimiz

Fabien Tarissan, Matthieu Latapy, Christophe Prieur

Complex networks are at the core of an intense research activity. However, in most cases, intricate and costly measurement procedures are needed to explore their structure. In some cases, these measurements rely on link queries: given two nodes, it is possible to test the existence of a link between them. These tests may be costly, and thus minimizing their

Jiezhu Lin

The article gives a necessary and sufficient condition for a Frobenius manifold to be a CDV-structure. We show that there exists a positive definite CDV-structure on any semi-simple Frobenius manifold. We also compare three natural connections on a CDV-structure and conclude that the underlying Hermitian manifold of a non-trivial CDV-structure is not a Kahle

Oussama Allali, Matthieu Latapy, Clemence Magnien

Collecting information about user activity in peer-to-peer systems is a key but challenging task. We describe here a distributed platform for doing so on the eDonkey network, relying on a group of honeypot peers which claim to have certain files and log queries they receive for these files. We then conduct some measurements with typical scenarios and use the

F. Bagarello

In this paper we continue our systematic analysis of the operatorial approach previously proposed in an economical context and we discuss a {\em mixed} toy model of a simplified stock market, i.e. a model in which the price of the shares is given as an input. We deduce the time evolution of the portfolio of the various traders of the market, as well as of ot

J. Maíz Apellániz

It is currently common to use spatially unresolved multi-filter broad-band photometry to determine the masses of individual stellar clusters (and hence the cluster mass function, CMF). I analyze the stochastic effects introduced by the sampling of the stellar initial mass function (SIMF) in the derivation of the individual masses and the CMF and I establish

F. Bagarello, M. R. Abdollahpour, S. Triolo

We apply the orthonormalization procedure previously introduced by two of us and adopted in connection with coherent states to Gabor frames and other examples. For instance, for Gabor frames we show how to construct $g(x)\in L^2(\Bbb{R})$ in such a way the functions $g_{\underline n}(x)=e^{ian_1x}g(x+an_2)$, $\underline n\in\Bbb{Z}^2$ and $a$ some positive r

F. Bagarello

In this paper we continue our descriptions of stock markets in terms of some non abelian operators which are used to describe the portfolio of the various traders and other {\em observable} quantities. After a first prototype model with only two traders, we discuss a more realistic model of market with an arbitrary number of traders. For both models we find

Sanjeev K. Gupta, Prafulla K. Jha

A modified phonon confinement model considering the size distribution, an improved phonon dispersion curve and a confinement function is developed for the calculation of size dependent Raman spectra of the silicon (Si) nanocrystals. The model is capable in simultaneous calculation of the Raman shift, intensity and linewidth. The calculated size dependent red

Yuri Kondratiev, Yuri Kozitsky, Tanja Pasurek

Gibbs random fields corresponding to systems of real-valued spins (e.g. systems of interacting anharmonic oscillators) indexed by the vertices of unbounded degree graphs with a certain summability property are constructed. It is proven that the set of tempered Gibbs random fields is non-void and weakly compact, and that they obey uniform exponential integrab

A. Grüneis, J. Serrano, A. Bosak, M. Lazzeri

The two-dimensional mapping of the phonon dispersions around the $K$ point of graphite by inelastic x-ray scattering is provided. The present work resolves the longstanding issue related to the correct assignment of transverse and longitudinal phonon branches at $K$. We observe an almost degeneracy of the three TO, LA and LO derived phonon branches and a str

Nobutoshi Yasutake, Toshiki Maruyama, Toshitaka Tatsumi, Kenta Kiuchi

We study structures of general relativistic compact stars with exotic matter. Our study is based on axisymetric and stationary formalism including purely toroidal magnetic field. We also study the finite size effects of quark-hadron mixed phase on structures of magnetars. For hybrid stars, we find a characteristic distribution of magnetic field, which has a

A. Marin-Franch, A. Herrero, A. Lenorzer, F. Najarro

- Context: We present the results of a near-infrared photometric and spectroscopic study of the star forming region G61.48+0.09. - Aims: The purpose of this study is to characterize the stellar content of the cluster and to determine its distance, extinction, age and mass. - Methods: The stellar population was studied by using color-magnitude diagrams to sel

Giulia Gubitosi, Luca Pagano, Giovanni Amelino-Camelia, Alessandro Melchiorri

We show that the Cosmic Microwave Background (CMB) polarization data gathered by the BOOMERanG 2003 flight and WMAP provide an opportunity to investigate {\it in-vacuo} birefringence, of a type expected in some quantum pictures of space-time, with a sensitivity that extends even beyond the desired Planck-scale energy. In order to render this constraint more

Hong Guo, Y. P. Jing

We use a set of numerical N-body simulations to study the large-scale behavior of the reduced bispectrum of dark matter and compare the results with the second-order perturbation theory and the halo models for different halo mass functions. We find that the second-order perturbation theory (PT2) agrees with the simulations fairly well on large scales of k<0.

Alessandro Mossa, Josep Maria Huguet, Felix Ritort

We present two examples of how single-molecule experimental techniques applied to biological systems can give insight into problems within the scope of equilibrium and nonequilibrium mesoscopic thermodynamics. The first example is the mapping of the free energy landscape of a macromolecule, the second the experimental verification of Crooks' fluctuation theo

D0 Collaboration, V. Abazov

We present measurements of the top quark mass in ttbar candidate events with two final state leptons using 1 inverse fb of data collected by the D0 experiment. Our data sample is selected by requiring two fully identified leptons or by relaxing one lepton requirement to an isolated track if at least one jet is tagged as a b jet. The top quark mass is extract

G. Miniutti, A. C. Fabian, W. N. Brandt, L. C. Gallo

We report a dramatic variability event in the X-ray history of the Narrow-Line quasar PHL 1092 (z=0.396). Our latest 2008 XMM-Newton observation reveals a flux drop of ~200 with respect to the previous observation performed about 4.5 years earlier, and a drop of ~135 with respect to its historical flux. Despite the huge X-ray variation, the UV flux remains c

Bernhard Eckl, Martin Horsch, Jadran Vrabec, Hans Hasse

At the Institute for Thermodynamics and Thermal Process Engineering (ITT) about 100 molecular models for pure substances have been developed so far. These models reproduce vapor pressure, saturated liquid density, and enthalpy of vaporization with a technical accuracy of less than 5%, less than 1%, and less than 5% deviation compared to experimental data, re

Pierre Lesaffre, Steven A. Balbus, Henrik Latter

We run mean-field shearing-box numerical simulations with a temperature-dependent resistivity and compare them to a reduced dynamical model. Our simulations reveal the co-existence of two quasi-steady states, a `quiet&#39; state and an `active&#39; turbulent state, confirming the predictions of the reduced model. The initial conditions determine on which sta

N. M. R. Peres, Shan-Wen Tsai, J. E. Santos, R. M. Ribeiro

We study the local density of states at and around a substituting impurity and use these results to compute current versus bias characteristic curves of Scanning Tunneling Microscopy (STM) experiments done on the surface of graphene. This allow us to detect the presence of substituting impurities on graphene. The case of vacancies is also analyzed. We find t

Franz X. Bronold, H. Fehske, H. Kersten, H. Deutsch

We recently questioned the treatment of a dust particle as a perfect absorber for electrons and ions and proposed a surface model for the charge of a dust particle in a quiescent plasma which combines the microscopic physics at the grain boundary (sticking into and desorption from external surface states) with the macrophysics of the discharge (plasma collec

A. De Falco, R. Arnaldi, K. Banicz, K. Borer

NA60 measured dimuon production in p-A and In-In collisions at the CERN SPS. This paper presents a high statistics measurement of $\phi$ meson production in In-In collisions at 158 AGeV. Both the transverse momentum, rapidity, decay angular distributions and the absolute yield were measured as a function of centrality. The results are compared to previous me

C. Joblin, O. Berne, A. Simon, G. Mulas

Polycyclic Aromatic Hydrocarbons (PAHs) are considered as a major constituent of interstellar dust. They have been proposed as the carriers of the Aromatic Infrared Bands (AIBs) observed in emission in the mid-IR. They likely have a significant contribution to various features of the extinction curve such as the 220 nm bump,the far-UV rise and the diffuse in

Fredrik Kuivinen

Let $(L; \sqcap, \sqcup)$ be a finite lattice and let $n$ be a positive integer. A function $f : L^n \to \mathbb{R}$ is said to be submodular if $f(\tup{a} \sqcap \tup{b}) + f(\tup{a} \sqcup \tup{b}) \leq f(\tup{a}) + f(\tup{b})$ for all $\tup{a}, \tup{b} \in L^n$. In this paper we study submodular functions when $L$ is a diamond. Given oracle access to $f$