April 2009 arXiv papers — page 4

Orsolya Kálmán, Tamás Kiss, Péter Földi

We propose a scheme to implement the one-dimensional coined quantum walk with electrons transported through a two-dimensional network of spintronic semiconductor quantum rings. The coin degree of freedom is represented by the spin of the electron, while the discrete position of the walker corresponds to the label of the rings in one of the spatial directions

Michael Blank

A new class of exclusion type processes acting in continuum with synchronous updating is introduced and studied. Ergodic averages of particle velocities are obtained and their connections to other statistical quantities, in particular to the particle density (the so called Fundamental Diagram) is analyzed rigorously. The main technical tool is a "dynamic

L. Sriramkumar

This article provides an introductory review of inflation and cosmological perturbation theory. I begin by motivating the need for an epoch of inflation during the early stages of the radiation dominated era, and describe how inflation is typically achieved using scalar fields. Then, after an overview of linear cosmological perturbation theory, I derive the

Michal Karpinski, Czeslaw Radzewicz, Konrad Banaszek

We report experimental determination of the phase-matching function for type-II three-wave mixing in a periodically poled KTiOPO_4 waveguide in the 792-815 nm spectral region. The measurement was performed by sum-frequency generation of spectrally tuned fundamental components. Strong dependence of the observed signal on the excited spatial modes in the waveg

E. Y. Shchekinova

This paper has been withdrawn by the author due to a errors in figure 3,4

G. Bårdsen, E. Tölö, A. Harju

We have studied the spin structure of circular four-electron quantum rings using tunable confinement potentials. The calculations were done using the exact diagonalization method. Our results indicate that ringlike systems can have oscillatory flips between ferromagnetic and antiferromagnetic behaviour as a function of the magnetic field. Furthermore, at con

Anika C. Pflanzer, Sascha Zöllner, Peter Schmelcher

We study the ground-state properties and quantum dynamics of few-boson mixtures with strong inter-species repulsion in one-dimensional traps. If one species localizes at the center, e.g., due to a very large mass compared to the other component, it represents an effective barrier for the latter and the system can be mapped onto identical bosons in a double w

Markus Lazar

In this paper we present the equations of motion of a moving screw dislocation in the framework of the translation gauge theory of dislocations. In the gauge field theoretical formulation, a dislocation is a massive gauge field. We calculate the gauge field theoretical solutions of a uniformly moving screw dislocation. We give the subsonic and supersonic sol

H. Bartosik, J. Klepp, C. Schmitzer, S. Sponar

We performed an experimental test of the Kochen-Specker theorem based on an inequality derived from the Peres-Mermin proof, using spin-path (momentum) entanglement in a single neutron system. Following the strategy proposed by Cabello et al. [Phys. Rev. Lett. 100, 130404 (2008)], a Bell-like state was generated and three expectation values were determined. T

Tobias Hurth, Werner Porod

We consider scenarios with large flavour violating entries in the squark mass matrices focusing on the mixing between second and third generation squarks. These entries govern both, flavour violating low energy observables on the one hand and squark and gluino decays on the other hand. We first discuss the constraints on the parameter space due to the recent

M. Pizzi

The Hawking radiation in the semi-classical approach is re-considered. In the so-called "Angheben method" for the calculation of the imaginary part of the action it was missed the temporal part contribution. This has been recently noticed by Akhmedov et \textsl{al.}, but also there the time part was not properly considered, the sign being reversed. W

Hartmut Weiss

We develop the deformation theory of hyperbolic cone-3-manifolds with cone-angles less than $2π$, i.e. contained in the interval $(0,2π)$. In the present paper we focus on deformations keeping the topological type of the cone-manifold fixed. We prove local rigidity for such structures. This gives a positive answer to a question of A. Casson.

Youngman Kim, Yumi Ko, Sang-Jin Sin

We study the density driven symmetry breaking in holographic superconductors by considering the positive mass squared case. We show that even for the positive $m^2$, a scalar condensation still forms, provided the chemical potential is high enough. As $m^2$ increases, the phase space folds due to the non-linearity of the equations of motion, and two nearby p

Bin Chen, Qing-Guo Huang

We construct the general renormalizable actions for the scalar field and the gauge field at a Lifshitz point characterized by the dynamical critical exponent $z$. The Lorentz invariance is broken down in the UV region, but is recovered in the IR limit. Even though the theories are UV complete, the speed of light is related to the momentum by $z(k/M)^{z-1}$ w

H. Oberhofer, J. Blumberger

We present a plane-wave basis set implementation of charge constrained density functional molecular dynamics (CDFT-MD) for simulation of electron transfer reactions in condensed phase systems. Following earlier work of Wu et al. Phys. Rev. A 72, 024502 (2005), the density functional is minimized under the constraint that the charge difference between donor a

Raka Dona Ray Mandal, Sushan Konar, Mira Dey, Jishnu Dey

The single glitch observed in PSR B1821-24, a millisecond pulsar in M28, is unusual on two counts. First, the magnitude of this glitch is at least an order of magnitude smaller ($Δν/ ν\sim 10^{-11}$) than the smallest glitch observed to date. Secondly, all other glitching pulsars have strong magnetic fields with $B \gsim 10^{11} G$ and are young, whereas PSR

Kenta Kiuchi, Yuichiro Sekiguchi, Masaru Shibata, Keisuke Taniguchi

General relativistic simulations for the merger of binary neutron stars are performed as an extension of a previous work\cite{Shibata:2006nm}. We prepare binary neutron stars with a large initial orbital separation and employ the moving-puncture formulation, which enables to follow merger and ringdown phases for a long time, even after black hole formation.

Amin Aminzadeh Gohari, Venkat Anantharam

The best known inner bound on the two-receiver general broadcast channel without a common message is due to Marton [3]. This result was subsequently generalized in [p. 391, Problem 10(c) 2] and [4] to broadcast channels with a common message. However the latter region is not computable (except in certain special cases) as no bounds on the cardinality of its

Pierdomenico Paolino, Bruno Tiribilli, Ludovic Bellon

Measurements of the deflection induced by thermal noise have been performed on a rectangular atomic force microscope cantilever in air. The detection method, based on polarization interferometry, can achieve a resolution of 1E-14 m/rtHz in the frequency range 1 kHz ? 800 kHz. The focused beam from the interferometer probes the cantilever at different positio

Wontae Kim, Edwin J. Son

In the dimensionally reduced model of the 2+1 dimensional cosmological massive gravity, we obtain the central charges of the two types of the black hole based on the entropy function method. One is for the BTZ black hole and the other one is actually for the warped AdS$_3$ black hole.

Alejandro Ayala, Adnan Bashir, Alfredo Raya, Angel Sánchez

Working in the linear sigma model with quarks, we compute the finite-temperature effective potential in the presence of a weak magnetic field, including the contribution of the pion ring diagrams and considering the sigma as a classical field. In the approximation where the pion self-energy is computed perturbatively, we show that there is a region of the pa

Anne Shiu, Bernd Sturmfels

Siphons in a chemical reaction system are subsets of the species that have the potential of being absent in a steady state. We present a characterization of minimal siphons in terms of primary decomposition of binomial ideals, we explore the underlying geometry, and we demonstrate the effective computation of siphons using computer algebra software. This lea

Kang Kim, Kunimasa Miyazaki, Shinji Saito

We study slow dynamics of particles moving in a matrix of immobile obstacles using molecular dynamics simulations. The glass transition point decreases drastically as the obstacle density increases. At higher obstacle densities, the dynamics of mobile particles changes qualitatively from glass-like to a Lorentz-gas-like relaxation. This crossover is studied

Dachun Yang, Yuan Zhou

Let ${\mathcal X}$ be an RD-space with $μ({\mathcal X})=\infty$, which means that ${\mathcal X}$ is a space of homogeneous type in the sense of Coifman and Weiss and its measure has the reverse doubling property. In this paper, we characterize the atomic Hardy spaces $H^p_{\rm at}(\{\mathcal X})$ of Coifman and Weiss for $p\in(n/(n+1),1]$ via the radial maxi

Enrique Vazquez-Semadeni, Gilberto C. Gomez, A. Katharina Jappsen, Javier Ballesteros-Paredes

We investigate the properties of "star forming regions" in a previously published numerical simulation of molecular cloud formation out of compressive motions in the warm neutral atomic interstellar medium, neglecting magnetic fields and stellar feedback. In this simulation, the velocity dispersions at all scales are caused primarily by infall motions rather

Jihun Park, Joonyeong Won

We classify all the effective anticanonical divisors on weak del Pezzo surfaces. Through this classification we obtain the smallest number among the log canonical thresholds of effective anticanonical divisors on a given Gorenstein canonical del Pezzo surface.

M. G. Faux, S. J. Gates,, T. Hubsch

A minimal representation of the N = 8 extended worldline supersymmetry, known as the `ultra-multiplet', is closely related to a family of supermultiplets with the same, E(8) chromotopology. We catalogue their effective symmetries and find a Spin(4) x Z(2) subgroup common to them all, which explains the particular basis used in the original construction.

F. T. Brandt, J. Frenkel, D. G. C. McKeon, J. B. Siqueira

We derive a closed form expression for the sum of all the infrared divergent contributions to the free-energy of a gas of gravitons. An important ingredient of our calculation is the use of a gauge fixing procedure such that the graviton propagator becomes both traceless and transverse. This has been shown to be possible, in a previous work, using a general

K. Blaum, Sz. Nagy, G. Werth

The technique of Penning trap mass spectrometry is briefly reviewed particularly in view of precision experiments on unstable nuclei, performed at different facilities worldwide. Selected examples of recent results emphasize the importance of high-precision mass measurements in various fields of physics.

H. L. Crawford, P. F. Mantica, J. S. Berryman, R. Broda

$β$ decay of the $^{61}$Cr$_{37}$ ground state has been studied. A new half-life of 233 +/- 11 ms has been deduced, and seven delayed $γ$ rays have been assigned to the daughter, $^{61}$Mn$_{36}$. The low-energy level structure of $^{61}$Mn$_{36}$ is similar to that of the less neutron-rich $^{57,59}$Mn nuclei. The odd-A $_{25}$Mn isotopes follow the systema

Dirk Beyer, Alessandro Cimatti, Alberto Griggio, M. Erkan Keremoglu

The construction and analysis of an abstract reachability tree (ART) are the basis for a successful method for software verification. The ART represents unwindings of the control-flow graph of the program. Traditionally, a transition of the ART represents a single block of the program, and therefore, we call this approach single-block encoding (SBE). SBE may

George Tsatsaronis, Maria Halkidi, Emmanouel A. Giakoumakis

Open Source Software (OSS) often relies on large repositories, like SourceForge, for initial incubation. The OSS repositories offer a large variety of meta-data providing interesting information about projects and their success. In this paper we propose a data mining approach for training classifiers on the OSS meta-data provided by such data repositories. T

F. J. Montes Ruiz-Cabello, H. Kusumaatmaja, M. A. Rodriguez-Valverde, J. M. Yeomans

We model an infinitely long liquid bridge confined between two plates chemically patterned by stripes of same width and different contact angle, where the three-phase contact line runs, on average, perpendicular to the stripes. This allows us to study the corrugation of a contact line in the absence of pinning. We find that, if the spacing between the plates

N. Metwally

The susceptibility of the transformed information to the filed and system parameters is investigated for the Kane solid state computer. It has been shown, that the field polarization and the initial state of the system play the central roles on the abrupt and gradual quench of the purity and the fidelity. If the field and the initial state are in different p

Noriyuki Matsunaga, Michael W. Feast, John W. Menzies

JHKs magnitudes corrected to mean intensity are estimated for LMC type II Cepheids in the OGLE-III survey. Period-luminosity (PL) relations are derived in JHKs as well as in a reddening-free VI parameter. Within the uncertainties the BL Her stars (P < 4 d) and the W Vir stars (P = 4 to 20 d) are co-linear in these PL relations. The slopes of the infrared rel

Sergio S. Gomez, Rodolfo H. Romero

The binding energy of a negatively charged hydrogenic impurity with on- and off-center position in a spherical Gaussian quantum dot was calculated with the configuration interaction method. Our calculations show that $E_b$ is always positive for on-center impurities with a maximum near to the radius for one-electron stability of the potential well $R_c$. For

A. Adem, A. Bahri, F. R. Cohen, S. Gitler

Let $X_{\bullet}$ denote a simplicial space. The purpose of this note is to record a decomposition of the suspension of the individual spaces $X_n$ occurring in $X_{\bullet}$ in case the spaces $X_n$ satisfy certain mild topological hypotheses and where these decompositions are natural for morphisms of simplicial spaces. In addition, the summands of $X_n$ wh

David K. Lai, Constance M. Rockosi, Michael Bolte, Jennifer A. Johnson

As part of a program to measure abundance ratios in stars beyond 15 kpc from the Galactic center, we have discovered a metal-poor star in the outer halo with a unique chemical signature. We originally identified it in the Sloan Extension for Galactic Understanding and Exploration (SEGUE) survey as a distant metal-poor star. We obtained a follow-up spectrum u

M. Casolino, The Pamela collaboration

PAMELA is a satellite borne experiment designed to study with great accuracy cosmic rays of galactic, solar, and trapped nature in a wide energy range (protons: 80 MeV-700 GeV, electrons 50 MeV-400 GeV). Main objective is the study of the antimatter component: antiprotons (80 MeV-190 GeV), positrons (50 MeV-270 GeV) and search for antimatter with a precision

A. M. Ghezelbash

We construct exact solutions to five-dimensional Einstein-Maxwell theory based on Atiyah-Hitchin space. The solutions cannot be written explicitly in a closed form, so their properties are investigated numerically. The five-dimensional metric is regular everywhere except on the location of original bolt in four-dimensional Atiyah-Hitchin base space. On each

M. T. Schuster, M. Marengo, J. L. Hora, G. G. Fazio

We present sub-arcsec angular resolution, high-Strehl ratio mid-IR adaptive optics images of the powerful OH/IR source and cool hypergiant NML Cyg at 8.8, 9.8 and 11.7 um. These images reveal once more the complexity in the dusty envelope surrounding this star. We spatially resolve the physical structures (radius ~0.14&#34;, ~240 AU adopting a distance of 1.

Daniel Kneezel, Igor Kriz

We compute the completion of the Verlinde algebra of a simply connected simple compact Lie group $G$ at the augmentation ideal of the representation ring. By results of Freed, Hopkins, Teleman and C.Dwyer and Lahtinen, this gives a computation of (non-equivariant) twisted $K$-theory of the free loop space of $BG$.

T. Schenkel, C. C. Lo, C. D. Weis, A. Schuh

The formation of quantum computer test structures in silicon by ion implantation enables the characterization of spin readout mechanisms with ensembles of dopant atoms and the development of single atom devices. We briefly review recent results in the characterization of spin dependent transport and single ion doping and then discuss the diffusion and segreg

S. Descotes-Genon, N. Offen

We summarize a recent calculation of the evolution kernels of the two-particle B-meson distribution amplitudes $ϕ_+$ and $ϕ_-$ taking into account three-particle contributions. In addition to a few phenomenological comments, we give as a new result the evolution kernel of the combination of three-particle distribution amplitudes $Ψ_A-Ψ_V$ and confirm constra

Cyril Allauzen, Mehryar Mohri

The problem of computing the edit-distance between a string and a finite automaton arises in a variety of applications in computational biology, text processing, and speech recognition. This paper presents linear-space algorithms for computing the edit-distance between a string and an arbitrary weighted automaton over the tropical semiring, or an unambiguous

D. A. Garanin

Dissipative spin-tunneling transitions at biased resonances in molecular magnets such as Mn-12 Ac are controlled by the dipolar field that can bring the system on and off resonance. It is shown that this leads to spin relaxation in form of propagating fronts of tunneling, with the dipolar field adjusting self-consistently to provide a zero bias within the fr

Bernard Badzioch, Wojciech Dorabiala, John R. Klein, Bruce Williams

We show that the smooth torsion of bundles of manifolds constructed by Dwyer, Weiss, and Williams satisfies the axioms for higher torsion developed by Igusa. As a consequence we obtain that the smooth Dwyer-Weiss-Williams torsion is proportional to the higher torsion of Igusa and Klein.

Nikolai Shaposhnikov, Lev Titarchuk, Philippe Laurent

We report on the Suzaku observation of neutron star low-mass X-ray binary Cygnus X-2 which reveals a presence of the iron K_alpha emission line. The line profile shows a significant red wing. This discovery increases the number of neutron star sources where red-skewed iron lines were observed and strongly suggests that this phenomenon is common not only in b

T. A. Kaplan

The ground state phase diagram is determined for the frustrated classical Heisenberg chain with added nearest-neighbor biquadratic exchange interactions. There appear ferromagnetic, incommensurate-spiral, and up-up-down-down phases; a lock-in transition occurs at the spiral boundary. The model contains an isotropic version of the ANNNI model; it is also clos

Sean M. Carroll, Heywood Tam, Ingunn Kathrine Wehus

We consider a theory of gravity in which a symmetric two-index tensor in Minkowski spacetime acquires a vacuum expectation value (vev) via a potential, thereby breaking Lorentz invariance spontaneously. When the vev breaks all the generators of the Lorentz group, six Goldstone modes emerge, two linear combinations of which have properties that are identical

Nadzeya Bedziuk, Aleh Yablonski

We consider an ordinary nonlinear differential equation with generalized coefficients as an equation in differentials in algebra of new generalized functions. Then the solution of such equation will be a new generalized function. In the article we formulate necessary and sufficient conditions when the solution of the given equation in algebra of new generali

Hans Jockers, Masoud Soroush

In this work we compute relative periods for B-branes, realized in terms of divisors in a compact Calabi-Yau hypersurface, by means of direct integration. Although we exemplify the method of direct integration with a particular Calabi-Yau geometry, the recipe automatically generalizes for divisors in other Calabi-Yau geometries as well. From the calculated r

C. Mund, O. Legeza, R. M. Noack

We examine the phase diagram of the half-filled one-dimensional extended Hubbard model using quantum information entropies within the density-matrix renormalization group. It is well known that there is a charge-density-wave phase at large nearest-neighbor and small on-site Coloumb repulsion and a spin-density-wave at small nearest-neighbor and large on-site

Mikhail J. Atallah, Marina Blanton, Michael T. Goodrich, Stanislas Polu

This paper studies a discrepancy-sensitive approach to dynamic fractional cascading. We provide an efficient data structure for dominated maxima searching in a dynamic set of points in the plane, which in turn leads to an efficient dynamic data structure that can answer queries for nearest neighbors using any Minkowski metric. We provide an efficient data st

G. Domenech, H. Freytes, C. de Ronde

Many worlds interpretations (MWI) of quantum mechanics avoid the measurement problem by considering every term in the quantum superposition as actual. A seemingly opposed solution is proposed by modal interpretations (MI) which state that quantum mechanics does not provide an account of what `actually is the case&#39;, but rather deals with what `might be th

Robert D. Edwards

This article is one of three highly influential articles on the topology of manifolds written by Robert D. Edwards in the 1970&#39;s but never published. Organizers of the Workshops in Geometric Topology (http://www.uwm.edu/~craigg/workshopgtt.htm) with the support of the National Science Foundation have facilitated the preparation of electronic versions of

Kavan Modi, E. C. G. Sudarshan

In a recent letter one of us pointed out how differences in preparation procedures for quantum experiments can lead to non-trivial differences in the results of the experiment. The difference arise from the initial correlations between the system and environment. Therefore, any quantum experiment that is prone to the influences from the environment must be p

Johan Öinert

In this paper we provide necessary and sufficient conditions for strongly group graded rings to be simple. For a strongly group graded ring $R = \bigoplus_{g\in G} R_g$ the grading group $G$ acts, in a natural way, as automorphisms of the commutant of the neutral component subring $R_e$ in $R$ and of the center of $R_e$. We show that if $R$ is a strongly $G$

F. von Oppen, F. Guinea, E. Mariani

Smoothly varying lattice strain in graphene affects the Dirac carriers through a synthetic gauge field. When the lattice strain is time dependent, as in connection with phononic excitations, the gauge field becomes time dependent and the synthetic vector potential is also associated with an electric field. We show that this synthetic electric field has obser

Vincenzo Di Gennaro, Davide Franco

Let $Z$ be a closed subscheme of a smooth complex projective complete intersection variety $Y\subseteq \Ps^N$, with $dim Y=2r+1\geq 3$. We describe the Néron-Severi group $NS_r(X)$ of a general smooth hypersurface $X\subset Y$ of sufficiently large degree containing $Z$.

Fanny Kassel

Let G be the set of k-points of a connected semisimple algebraic group of k-rank one over a nonarchimedean local field k. We describe all finitely generated torsion-free discrete subgroups of G\times G acting properly discontinuously and cocompactly on G by left and right multiplication. We prove that after a small deformation in G\times G such a discrete su

R. Paškauskas, G. De Ninno

We propose an efficient method to compute Lyapunov exponents and Lyapunov eigenvectors of long-range interacting many-particle systems, whose dynamics is described by the Vlasov equation. We show that an expansion of a distribution function using Hermite modes (in momentum variable) and Fourier modes (in configuration variable) converges fast if an appropria

Eros Mariani, Felix von Oppen

Motivated by recent experiments, we investigate the electron-vibron coupling in suspended carbon nanotube quantum dots, starting with the electron-phonon coupling of the underlying graphene layer. We show that the coupling strength depends sensitively on the type of vibron and is strongly sample dependent. The coupling strength becomes particularly strong wh

Benoit Bertrand, Erwan Brugallé

We construct a polynomial of degree d in two variables whose Hessian curve has (d-2)^2 connected components using Viro patchworking. In particular, this implies the existence of a smooth real algebraic surface of degree d in RP^3 whose parabolic curve is smooth and has d(d-2)^2 connected components.

Frazer N. Owen, G. E. Morrison

We present the results of spectroscopy using HYDRA on the WIYN 3.5m telescope of objects in the deep SWIRE radio field. The goal of the project was to determine spectroscopic redshifts for as many of the brighter objects in the field as possible, especially those detected in the radio and at 24 microns. These redshifts are primarily being used in studies of

Revnivtsev M., Sazonov S., Churazov E., Forman W.

An unresolved X-ray glow (at energies above a few kiloelectronvolts) was discovered about 25 years ago and found to be coincident with the Galactic disk -the Galactic ridge X-ray emission. This emission has a spectrum characteristic of a 1e8 K optically thin thermal plasma, with a prominent iron emission line at 6.7 keV. The gravitational well of the Galacti

Luciano Mari, Marco Rigoli, Alberto G. Setti

In this paper we obtain generalized Keller-Osserman conditions for wide classes of differential inequalities on weighted Riemannian manifolds of the form $L u\geq b(x) f(u) \ell(|\nabla u|)$ and $L u\geq b(x) f(u) \ell(|\nabla u|) - g(u) h(|\nabla u|)$, where $L$ is a non-linear diffusion-type operator. Prototypical examples of these operators are the $p$-La

William B. Sparks, James Hough, Thomas A. Germer, Feng Chen

The identification of a universal biosignature that could be sensed remotely is critical to the prospects for success in the search for life elsewhere in the universe. A candidate universal biosignature is homochirality, which is likely to be a generic property of all biochemical life. Due to the optical activity of chiral molecules, it has been hypothesized

Alessandro Fontana

This paper deals with a model of cellular growth called &#34;Epigenetic Tracking&#34;, whose key features are: i) distinction bewteen &#34;normal&#34; and &#34;driver&#34; cells; ii) presence in driver cells of an epigenetic memory, that holds the position of the cell in the driver cell lineage tree and represents the source of differentiation during develop

Eman Hamza, Spyridon Michalakis, Bruno Nachtergaele, Robert Sims

We consider quantum spin systems defined on finite sets $V$ equipped with a metric. In typical examples, $V$ is a large, but finite subset of Z^d. For finite range Hamiltonians with uniformly bounded interaction terms and a unique, gapped ground state, we demonstrate a locality property of the corresponding ground state projector. In such systems, this groun

M. Godart, A. Noels, M. -A. Dupret

Thanks to their past history on the main sequence phase, supergiant massive stars develop a convective shell around the helium core. This intermediate convective zone (ICZ) plays an essential role in governing which g-modes are excited. Indeed a strong radiative damping occurs in the high density radiative core but the ICZ acts as a barrier preventing the pr

Bang-Rong Zhou

The color number $N_c$-dependence of the interplay between quark-antiquark condensates $<\bar{q}q>$ and diquark condensates $<qq>$ in vacuum in two-flavor four-fermion interaction models is researched. The results show that the $G_S$-$H_S$ (the coupling constant of scalar $(\bar{q}q)^2$-scalar $(qq)^2$ channel) phase diagrams will be qualitatively consistent

Y. Revaz, D. Pfenniger, F. Combes, F. Bournaud

The near proportionality between HI and dark matter in outer galactic disks prompted us to run N-body simulations of galactic disks in which the observed gas content is supplemented by a dark gas component representing between zero and five times the visible gas content. While adding baryons in the disk of galaxies may solve some issues, it poses the problem

Jadran Vrabec, J. Gross

A systematic investigation on vapor-liquid equilibria (VLE) of dipolar and quadrupolar fluids is carried out by molecular simulation to develop a new Helmholtz energy contribution for equations of state (EOS). Twelve two-center Lennard-Jones plus point dipole and point quadrupole model fluids (2CLJDQ) are studied for different reduced dipolar moments mu^{*2}

Y. Revaz, P. Jablonka, T. Sawala, V. Hill

We present a large sample of fully self-consistent hydrodynamical Nbody/Tree-SPH simulations of isolated dwarf spheroidal galaxies (dSphs). It has enabled us to identify the key physical parameters and mechanisms at the origin of the observed variety in the Local Group dSph properties. The initial total mass (gas + dark matter) of these galaxies is the main

Jose Bioucas-Dias

This paper presents a new linear hyperspectral unmixing method of the minimum volume class, termed \emph{simplex identification via split augmented Lagrangian} (SISAL). Following Craig&#39;s seminal ideas, hyperspectral linear unmixing amounts to finding the minimum volume simplex containing the hyperspectral vectors. This is a nonconvex optimization problem

Hai Wang*, Xudong Yang, Shujing Li, Chunhong Zhang

The laser spectroscopy with a narrow linewidth and high signal to noise ratio (S/N) is very important in the precise measurement of optical frequencies. Here, we present a novel high-resolution backward resonance Bragg-scattering (RBS) spectroscopy from a population difference grating (PDG). The PDG is formed by a standing-wave (SW) pump field in thermal 87R

Gimmy Alex Fernandez Ramirez, Jadran Vrabec, Hans Hasse

Self- and binary Maxwell-Stefan diffusion coefficients were determined by equilibrium molecular dynamics simulations with the Green-Kubo method. This study covers self-diffusion coefficients at liquid states for eight pure fluids, i.e. F$_2$, N$_2$, CO$_2$, CS$_2$, C$_2$H$_6$, C$_2$H$_4$, C$_2$H$_2$ and SF$_6$ as well as Maxwell-Stefan diffusion coefficients

G. A. Fernandez, J. Vrabec, H. Hasse

Self diffusion coefficients and binary Maxwell-Stefan diffusion coefficients were determined by equilibrium molecular dynamics simulations with the Green-Kubo method. The study covers five pure fluids: neon, argon, krypton, xenon, and methane and three binary mixtures: argon+krypton, argon+xenon, and krypton+xenon. The fluids are modeled by spherical Lennard

Florencio Balboa Usabiaga, Daniel Duque

The identification of the interfacial molecules in fluid-fluid equilibrium is a long-standing problem in the area of simulation. We here propose a new point of view, making use of concepts taken from the field of computational geometry, where the definition of the &#34;shape&#34; of a set of point is a well-known problem. In particular, we employ the $α$-sha

Jaime Angulo, Marcia Scialom, Carlos Banquet

This paper has various goals: first, we develop a local and global well-posedness theory for the regularized Benjamin-Ono equation in the periodic setting, second, we show that the Cauchy problem for this equation (in both periodic and non-periodic case) cannot be solved by an iteration scheme based on the Duhamel formula for negative Sobolev indices, third,

T. Merker, J. Vrabec, H. Hasse

A molecular model for carbon dioxide is assessed regarding vapor-liquid quilibrium properties.Large deviations, being above 15 %, are found for vapor pressure and saturated vapor density in the entire temperature range.

Andreas Walther, Atia Amari, Stefan Kröll, Alexey Kalachev

The effects of high optical depth phenomena, such as superradiance, are investigated in potential quantum memory materials. The results may have relevance for several schemes, including CRIB, AFC and EIT-based quantum memories, which are based on using ensembles as storage media. It is shown that strong superradiant effects, manifested as decay rates larger

Josep J. Masdemont, Luis Ortiz-Gracia

This paper proposes a new methodology to compute Value at Risk (VaR) for quantifying losses in credit portfolios. We approximate the cumulative distribution of the loss function by a finite combination of Haar wavelets basis functions and calculate the coefficients of the approximation by inverting its Laplace transform. In fact, we demonstrate that only a f

Simon P Goodwin, M B N Kouwenhoven

We show that the same initial mass function (IMF) can result from very different modes of star formation from very similar underlying core and/or system mass functions. In particular, we show that the canonical IMF can be recovered from very similar system mass functions, but with very different mass ratio distributions within those systems. This is a conseq

B. Eckl, J. Vrabec, H. Hasse

An optimized molecular model for ammonia, which is based on a previous work of Kristoef et al., Mol. Phys. 97 (1999) 1129--1137, is presented. Improvements are achieved by including data on geometry and electrostatics from quantum mechanical calculations in a first model. Afterwards the parameters of the Lennard-Jones potential, modeling dispersive and repul

Natalya A. Zimbovskaya, Maija M. Kuklja

We theoretically analyzed inelastic effects in the electron transport through molecular junctions originating from electron-vibron interactions. The molecular bridge was simulated by a periodic chain of identical interacting hydrogen-like atoms providing a set of energy states for the electron tunneling. To avoid difficulties inevitably arising when advanced

Frédéric Hélein

This text is the extended version of a talk given at the conference Geometry, Topology, QFT and Cosmology hold from May 28 to May 30, 2008 at the Observatoire de Paris. We explore the notion of solder (or soldering form) in differential geometry and propose an alternative interpretation of it, motivated by the search of an accurate mathematical description o

Nicolas Raimbaud

Thirty years after the birth of foliations in the 1950&#39;s, André Haefliger has introduced a special property satisfied by holonomy pseudogroups of foliations on compact manifolds, called compact generation. Up to now, this is the only general property known about holonomy on compact manifolds. In this article, we give a Morita-invariant generalization of

J Ju, Z Li, G Mu, H-H Wen

The structural details in Pr1-xSrxFeAsO (1111) superconducting system are analyzed using data obtained from synchrotron X-ray diffraction and the structural parameters are carefully studied as the system is moving from non-superconducting to hole-doped superconducting with the Sr concentration. Superconductivity emerges when the Sr doping amount reaches 0.22

V. I. Yukalov, E. P. Yukalova

An insulating optical lattice with double-well sites is considered. In the case of the unity filling factor, an effective Hamiltonian in the pseudospin representation is derived. A method is suggested for manipulating the properties of the system by varying the shape of the double-well potential. In particular, it is shown that the atomic imbalance can be va

Yongsheng Jiang, Huan-Song Zhou

We study the following Schrödinger-Poisson system (P_λ){ll} -Δu + V(x)u+λϕ(x) u =Q(x)u^{p}, x\in \mathbb{R}^3 \\ -Δϕ= u^2, \lim\limits_{|x|\to +\infty}ϕ(x)=0, u>0, where $λ\geqslant0$ is a parameter, $1 < p < +\infty$, $V(x)$ and $Q(x)$ are sign-changing or non-positive functions in $ L^{\infty}(\mathbb{R}^3)$. When $V(x)\equiv Q(x)\equiv1$, D.Ruiz \cite{Rui

Igor Chilingarian, Alexandra Novikova, Veronique Cayatte, Francoise Combes

Lenticular galaxies are believed to form by a combination of environmental effects and secular evolution. We study the nearby disc-dominated S0 galaxy NGC 6340 photometrically and spectroscopically to understand the mechanisms of S0 formation and evolution in groups. We use SDSS images to build colour maps and light profile of NGC 6340 which we decompose usi

Klaus Bongartz, Guido Frank, Isabel Wolters

We study minimal disjoint degenerations for representations of tame quivers. In particular, we prove that their codimensions are bounded by 2. Therefore a quiver is Dynkin resp. Euclidean resp. wild iff the codimensions are 1 resp. bounded by 2 resp. unbounded. We explain also that for tame quivers the complete classification of all minimal disjoint degenera

T. Marrodan Undagoitia, F. von Feilitzsch, L. Oberauer, W. Potzel

The fluorescence decay-time constants have been measured for several scintillator mixtures based on phenyl-o-xylylethane (PXE) and linear alkylbenzene (LAB) solvents. The resulting values are of relevance for the physics performance of the proposed large-volume liquid scintillator detector LENA (Low Energy Neutrino Astronomy). In particular, the impact of th

Shun Takeuchi, Shin Mineshige, Ken Ohsuga

Photon trapping and outflow are two key physics associated with the supercritical accretion flow. We investigate the conflict between these two processes based on two-dimensional radiation-hydrodynamic (RHD) simulation data and construct a simplified (radially) one-dimensional model. Mass loss due to outflow, which is not considered in the slim-disk model, w

J Bergli, Y M Galperin, B L Altshuler

The efficiency of the future devices for quantum information processing is limited mostly by the finite decoherence rates of the qubits. Recently a substantial progress was achieved in enhancing the time, which a solid-state qubit demonstrates a coherent dynamics. This progress is based mostly on a successful isolation of the qubits from external decoherence

T. Roy Choudhury

Reionization is a process whereby hydrogen (and helium) in the Universe is ionized by the radiation from first luminous sources. Theoretically, the importance of the reionization lies in its close coupling with the formation of first cosmic structures and hence there is considerable effort in modelling the process. We give a pedagogic overview of different a

Jen-Hsu Chang, Yu-Tung Chen

We investigate the integrable $(2+1)$-dimensional generalized dispersionless KP (GdKP) equation (or Manakov-Santinit system) from the Lax-Sato form. Several particular three-component reductions are considered so that the GdKP equation can be reduced to hydrodynamic systems. Then one can construct infinite exact solutions of GdKP by the generalized hodograph

Sanjiv Kumar Tiwari, P. Venkatakrishnan, Sanjay Gosain, Jayant Joshi

The force-free parameter $α$, also known as helicity parameter or twist parameter, bears the same sign as the magnetic helicity under some restrictive conditions. The single global value of $α$ for a whole active region gives the degree of twist per unit axial length. We investigate the effect of polarimetric noise on the calculation of global $α$ value and