June 2007 arXiv papers — page 42

James R. Lee, Assaf Naor, Yuval Peres

We show that an infinite weighted tree admits a bi-Lipschitz embedding into Hilbert space if and only if it does not contain arbitrarily large complete binary trees with uniformly bounded distortion. We also introduce a new metric invariant called Markov convexity, and show how it can be used to compute the Euclidean distortion of any metric tree up to unive

Jeremy Marzuola, Jason Metcalfe, Daniel Tataru

In this article we study global-in-time Strichartz estimates for the Schrödinger evolution corresponding to long-range perturbations of the Euclidean Laplacian. This is a natural continuation of a recent article of the third author, where it is proved that local smoothing estimates imply Strichartz estimates. In the aforementioned paper, the third author pro

N. Bastian, I. Konstantopoulos, L. J. Smith, G. Trancho

We present a detailed study of the stellar cluster M82F, using multi-band high resolution HST imaging and deep ground based optical slit and integral field spectroscopy. Using the imaging we create colour maps of the cluster and surrounding region in order to search for substructure. We find a large amount of substructure, which we interpret as the result of

R. J. White, J. M. Gabor, L. A. Hillenbrand

We present high-dispersion (R~16,000) optical (3900-8700 A) spectra of 390 stars obtained with the Palomar 60 inch telescope. The majority of stars observed are part of the Spitzer Legacy Science Program "The Formation and Evolution of Planetary Systems." Through detailed analysis we determine stellar properties for this sample, including radial and

Adam Logan, Ronald van Luijk

In this paper we present a new method to show that a principal homogeneous space of the Jacobian of a curve of genus two is nontrivial. The idea is to exhibit a Brauer-Manin obstruction to the existence of rational points on a quotient of this principal homogeneous space. In an explicit example we apply the method to show that a specific curve has infinitely

Maury Goodman

A magnetic detector such as MINOS which is measuring the sign of muons has to deal with issues of bending, which depend on the magnetic field configuration, and multiple scattering, which depends on the amount of material which is traversed. Above some momentum which depends on these factors, the momentum cannot be resolved. Issues related to measurement of

Philip Schreiner, Maury Goodman

MINOS is the first large magnetic detector deep underground and is the first to measure the muon charge ratio with high statistics in the region near 1 TeV.\cite{bib:adamson} An approximate formula for the muon charge ratio can be expressed in terms of $ε_π$ = 115 GeV, $ε_K$ = 850 GeV and $\ec$. The implications for K production in the atmosphere will be dis

Ya. B. Bazaliy

Current induced precession states in spin-transfer devices are studied in the case of large easy plane anisotropy (present in most experimental setups). It is shown that the effective one-dimensional planar description provides a simple qualitative understanding of the emergence and evolution of such states. Switching boundaries are found analytically for th

Christy A. Tremonti, John Moustakas, Aleksandar M. Diamond-Stanic

Numerical simulations suggest that active galactic nuclei (AGNs) play an important role in the formation of early-type galaxies by expelling gas and dust in powerful galactic winds and quenching star formation. However, the existence of AGN feedback capable of halting galaxy-wide star formation has yet to be observationally confirmed. To investigate this que

L. R. Arnaut

We investigate the effects of relatively rapid variations of the boundaries of an overmoded cavity on the stochastic properties of its interior acoustic or electromagnetic field. For quasi-static variations, this field can be represented as an ideal incoherent and statistically homogeneous isotropic random scalar or vector field, respectively. A physical mod

Sangwook Park, Patrick O. Slane, John P. Hughes, Koji Mori

We report on observations of the Galactic supernova remnant (SNR) G299.2$-$2.9 with the {\it Chandra X-Ray Observatory}. The high resolution images with {\it Chandra} resolve the X-ray-bright knots, shell, and diffuse emission extending beyond the bright shell. Interior to the X-ray shell is faint diffuse emission occupying the central regions of the SNR. Sp

Andrew L. Haynes, Clare E. Parnell

Null points are important locations in vector fields, such as a magnetic field. A new technique (a trilinear method for finding null points) is presented for finding null points over a large grid of points, such as those derived from a numerical experiment. The method was designed so that the null points found would agree with any fieldlines traced using the

Tommaso Treu, Jong-Hak Woo, Matthew A. Malkan, Roger D. Blandford

We combine Hubble Space Telescope images of a sample of 20 Seyfert galaxies at z=0.36 with spectroscopic information from the Keck Telescope to determine the black hole mass - spheroid luminosity relation (M-L), the Fundamental Plane (FP) of the host galaxies and the M-sigma relation. Assuming pure luminosity evolution, we find that the host spheroids had sm

Andrew C. Mshar, Jane C. Charlton, Ryan S. Lynch, Chris Churchill

We consider the evolution of strong (W_r(2796) > 0.3A) MgII absorbers, most of which are closely related to luminous galaxies. Using 20 high resolution quasar spectra from the VLT/UVES public archive, we examine 33 strong MgII absorbers in the redshift range 0.3 < z < 2.5. We compare and supplement this sample with 23 strong MgII absorbers at 0.4 < z < 1.4 o

D. Farrah, J. Bernard-Salas, H. W. W. Spoon, B. T. Soifer

(Abridged) We present R~600, 10-37um spectra of 53 ULIRGs at z<0.32, taken using the IRS on board Spitzer. All of the spectra show fine structure emission lines of Ne, O, S, Si and Ar, as well as molecular Hydrogen lines. Some ULIRGs also show emission lines of Cl, Fe, P, and atomic Hydrogen, and/or absorption features from C_2H_2, HCN, and OH. We employ dia

Maury Goodman

Two neutrino mixing angles have been measured, and much of the neutrino community is turning its attention to the unmeasured mixing angle, $\quq$, whose best limit comes from the reactor neutrino experiment CHOOZ.\cite{bib:chooz} New two detector reactor neutrino experiments are being planned, along with more ambitious accelerator experiments, to measure or

F. Ginelli, P. Poggi, A. Turchi, H. Chaté

A general method to determine covariant Lyapunov vectors in both discrete- and continuous-time dynamical systems is introduced. This allows to address fundamental questions such as the degree of hyperbolicity, which can be quantified in terms of the transversality of these intrinsic vectors. For spatially extended systems, the covariant Lyapunov vectors have

C. -Y. Huang, S. -E. Park, M. Pohl, C. D. Daniels

We employ the Monte Carlo particle collision code DPMJET3.04 to determine the multiplicity spectra of various secondary particles (in addition to $π^0$&#39;s) with $γ$&#39;s as the final decay state, that are produced in cosmic-ray ($p$&#39;s and $α$&#39;s) interactions with the interstellar medium. We derive an easy-to-use $γ$-ray production matrix for cosm

Hichem Geryville, Yacine Ouzrout, Abdelaziz Bouras, Nikolaos Sapidis

The new requirement for &#34;collaboration&#34; between multidisciplinary collaborators induces to exchange and share adequate information on the product, processes throughout the products&#39; lifecycle. Thus, effective capture of information, and also its extraction, recording, exchange, sharing, and reuse become increasingly critical. These lead companies

Bin Zhou, Xiaohua Zhu

In this note, we prove that on polarized toric manifolds the relative $K$-stability with respect to Donaldson&#39;s toric degenerations is a necessary condition for the existence of Calabi&#39;s extremal metrics, and also we show that the modified $K$-energy is proper in the space of $G_0$-invariant Kähler metrics for the case of toric surfaces which admit t

C. -Y. Huang, M. Pohl

This work presents preliminary results for the time-dependent cosmic-ray propagation in the Galaxy by a fully 3-dimensional Monte Carlo simulation. The distribution of cosmic-rays (both protons and helium nuclei) in the Galaxy is studied on various spatial scales for both constant and variable cosmic-ray sources. The continuous diffuse gamma-ray emission pro

B. M. Baughman, W. B. Atwood, R. P. Johnson, T. A. Porter

The Energetic Gamma-Ray Experiment Telescope (EGRET) experiment onboard the Compton Gamma-Ray Observatory (CGRO) has provided the most precise measurements of the gamma-ray sky to date. The EGRET measurements of the diffuse emission across the sky show an excess above 1 GeV. This ``GeV excess&#39;&#39; has been a topic of great debate and interest since its

Leonid P. Pryadko, Gregory Quiroz

Refocusing, or dynamical decoupling, is a coherent control technique where the internal dynamics of a quantum system is effectively averaged out by an application of specially designed driving fields. The method has originated in nuclear magnetic resonance, but it was independently discovered in atomic physics as a ``coherent destruction of tunneling&#39;&#3

Michael Behrisch, Amin Coja-Oghlan, Mihyun Kang

We establish central and local limit theorems for the number of vertices in the largest component of a random $d$-uniform hypergraph $\hnp$ with edge probability $p=c/\binnd$, where $(d-1)^{-1}+\eps<c<\infty$. The proof relies on a new, purely probabilistic approach, and is based on Stein&#39;s method as well as exposing the edges of $H_d(n,p)$ in several ro

N. Bastian, B. Ercolano, M. Gieles, E. Rosolowsky

Star-formation within galaxies appears on multiple scales, from spiral structure, to OB associations, to individual star clusters, and often sub-structure within these clusters. This multitude of scales calls for objective methods to find and classify star-forming regions, regardless of spatial size. To this end, we present an analysis of star-forming groups

Alessio Corti, Paul Hacking, János Kollár, Robert Lazarsfeld

This document contains notes from the lectures of Corti, Kollár, Lazarsfeld, and Mustaţă at the workshop ``Minimal and canonical models in algebraic geometry&#34; at MSRI, Berkeley, April 2007. The lectures give an overview of the recent advances on canonical and minimal models of algebraic varieties obtained by Hacon--McKernan and Birkar--Cascini--Hacon--Mc

M. Paternostro, S. Bose, M. S. Kim

We study the conditions for the probing of an environment affecting one party of a bipartite system of interacting objects by measurements operated only on the other element. We show that entanglement plays no crucial role in such an environment-characterization. On the other hand, if an interaction is established between the two parties, information can be

L. S. Geng, J. Meng, H. Toki

A Reflection ASymmetric Relativistic Mean Field (RAS-RMF) approach is developed by expanding the equations of motion for both the nucleons and the mesons on the eigenfunctions of the two-center harmonic-oscillator potential. The efficiency and reliability of the RAS-RMF approach are demonstrated in its application to the well-known octupole deformed nucleus

Peter Arnold, Guy D. Moore

Thermalization of quark-gluon plasmas in heavy-ion collisions is a difficult theoretical problem. One theoretical goal has been to understand the physics of thermalization in the relatively simplifying limit of arbitrarily high energy collisions, where the running coupling alpha_s is weak. One of the current roadblocks to achieving this goal is lack of knowl

Clifton Ealy, Krzysztof Krupinski, Anand Pillay

We study a model theoretic context (finite thorn rank, NIP, with finitely satisfiable generics) which is a common generalization of groups of finite Morley rank and definably compact groups in o-minimal structures. We show that assuming thorn rank 1, the group is abelian-by-finite, and assuming thorn rank 2 the group is solvable by finite. Also a field is al

David R. Wright

Modern society is permeated with computers, and the software that controls them can have latent, long-term, and immediate effects that reach far beyond the actual users of these systems. This places researchers in Computer Science and Software Engineering in a critical position of influence and responsibility, more than any other field because computer syste

Paola Cappellaro, Chandrasekhar Ramanathan, David G. Cory

We study experimentally a system comprised of linear chains of spin-1/2 nuclei that provides a test-bed for multi-body dynamics and quantum information processing. This system is a paradigm for a new class of quantum information devices that can perform particular tasks even without universal control of the whole quantum system. We investigate the extent of

Traian A. Pirvu, Gordan Zitkovic

We investigate the ergodic problem of growth-rate maximization under a class of risk constraints in the context of incomplete, Itô-process models of financial markets with random ergodic coefficients. Including {\em value-at-risk} (VaR), {\em tail-value-at-risk} (TVaR), and {\em limited expected loss} (LEL), these constraints can be both wealth-dependent(rel

J. Ruseckas, G. Juzeliunas, P. Ohberg, S. M. Barnett

We consider the propagation of slow light with an orbital angular momentum (OAM) in a moving atomic medium. We have derived a general equation of motion and applied it in analysing propagation of slow light with an OAM in a rotating medium, such as a vortex lattice. We have shown that the OAM of slow light manifests itself in a rotation of the polarisation p

Roby Cherian, Priya Mahadevan, Clas Persson

First principle calculations based on LDA/GGA approximation for the exchange functional underestimate the position of the semi core 3d levels in GaX (X = N, P and As) semiconductors. A self-interaction correction scheme within the LDA+U/GGA+U approximation is found to be sufficient to correct this discrepancy. A consequence of thiscorrection is that the band

Kasper Larsen, Gordan Zitkovic

The effectiveness of utility-maximization techniques for portfolio management relies on our ability to estimate correctly the parameters of the dynamics of the underlying financial assets. In the setting of complete or incomplete financial markets, we investigate whether small perturbations of the market coefficient processes lead to small changes in the age

Adrian Diaconu, Ye Tian

Let p be a prime number, F a totally real field such that [F(mu_p): F]=2 and [F:Q] is odd. For delta \in F^times, let [delta] denote its class in F^times/F^{times p}. In this paper, we show Main Theorem. There are infinitely many classes [delta]\in F^times/F^{times p} such that the twisted affine Fermat curves W_delta: X^p+Y^p=delta have no F-rational points

Kasper Larsen, Gordan Zitkovic

This paper provides a new version of the condition of Di Nunno et al. (2003), Ankirchner and Imkeller (2005) and Biagini and \{O}ksendal (2005) ensuring the semimartingale property for a large class of continuous stochastic processes. Unlike our predecessors, we base our modeling framework on the concept of portfolio proportions which yields a short self-con

S. R. Souza, R. Donangelo, W. G. Lynch, M. B. Tsang

We include in statistical model calculations the facts that in the nuclear multifragmentation process the fragments are produced within a given volume and have a finite size. The corrections associated with these constraints affect the partition modes and, as a consequence, other observables in the process. In particular, we find that the favored fragmenting

A. Mikovic

We show that if the flat-spacetime wavefunction in the spin network basis of Loop Quantum Gravity has a large-spin asymptotics given by Rovelli&#39;s ansatz then the corresponding graviton propagator has the correct large-distance asymptotics nonperturbatively and independently of the spin foam model used to describe the evolution operator. We also argue tha

D. A. Sofge

The SEMATECH sponsored J-88-E project teaming Texas Instruments with NeuroDyne (et al.) focused on Fault Detection and Classification (FDC) on a Lam 9600 aluminum plasma etch reactor, used in the process of semiconductor fabrication. Fault classification was accomplished by implementing a series of virtual sensor models which used data from real sensors (Lam

Claes Uggla

The existence of a singularity by definition implies a preferred scale--the affine parameter distance from/to the singularity of a causal geodesic that is used to define it. However, this variable scale is also captured by the expansion along the geodesic, and this can be used to obtain a regularized state space picture by means of a conformal transformation

Gordan Zitkovic

Existence of stochastic financial equilibria giving rise to semimartingale asset prices is established under a general class of assumptions. These equilibria are expressed in real terms and span complete markets or markets with withdrawal constraints.We deal with random endowment density streams which admit jumps and general time-dependent utility functions

Roger A. Chevalier

The association of long gamma-ray bursts (GRBs) with Type Ib/c supernovae implies that they explode into the winds of their Wolf-Rayet progenitor stars. Although the evolution of some GRB afterglows is consistent with expansion into a free wind, there is also good evidence for expansion into a constant density medium. The evidence includes the evolution of X

Julianna S. Tymoczko

This survey paper describes two geometric representations of the permutation group using the tools of toric topology. These actions are extremely useful for computational problems in Schubert calculus. The (torus) equivariant cohomology of the flag variety is constructed using the combinatorial description of Goresky-Kottwitz-MacPherson, discussed in detail.

D. A. Sofge, M. A. Potter, M. D. Bugajska, A. C. Schultz

Robotic hardware designs are becoming more complex as the variety and number of on-board sensors increase and as greater computational power is provided in ever-smaller packages on-board robots. These advances in hardware, however, do not automatically translate into better software for controlling complex robots. Evolutionary techniques hold the potential t

R. S. Thorne, A. D. Martin, W. J. Stirling, G. Watt

We present a preliminary set of updated NLO parton distributions. For the first time we have a quantitative extraction of the strange quark and antiquark distributions and their uncertainties determined from CCFR and NuTeV dimuon cross sections. Additional jet data from HERA and the Tevatron improve our gluon extraction. Lepton asymmetry data and neutrino st

S. P. Mikheev, A. Yu. Smirnov

Under certain conditions, the propagation of a beam of oscillating neutrinos in a variable-density medium takes the form of an almost complete transformation of the initial type of neutrino into another type. The depth of oscillations is then negligible. The transformation can occur in the cores and envelopes of collapsing stars.

Sayak Mukherjee, H. K. Janssen, B. Schmittmann

Starting from the well-known field theory for directed percolation, we describe an evolving population, near extinction, in an environment with its own nontrivial spatio-temporal dynamics. Here, we consider the special case where the environment follows a simple relaxational (Model A) dynamics. Two new operators emerge, with upper critical dimension of four,

L. Cieri, F. A. Schaposnik

We present an explicit classical dyon solution for the noncommutative version of the Yang-Mills-Higgs model (in the Prasad-Sommerfield limit) with a tehta term. We show that the relation between classical electric and magnetic charges also holds in noncommutative space. Extending the Noether approach to the case of a noncommutative gauge theory, we analyze t

François Rodier, Eric Férard

Nous étudions la non linéarité des fonctions définies sur F_{2^m} où $m$ est un entier impair, associées aux polynômes de degré 7 ou à des polynômes plus généraux. ----- We study the nonlinearity of the functions defined on F_{2^m} where $m$ is an odd integer, associated to the polynomials of degree 7 or more general polynomials.

Y. Z. Zhang, Masatoshi Imada

We study metal-insulator transitions between Mott insulators and metals. The transition mechanism completely different from the original dynamical mean field theory (DMFT) emerges from a cluster extension of it. A consistent picture suggests that the quasiparticle weight $Z$ remains nonzero through metals and suddenly jumps to zero at the transition, while t

D. E. MacLaughlin, Lei Shu, R. H. Heffner, J. E. Sonier

The effective superconducting penetration depth measured in the vortex state of PrOs4Sb12 using transverse-field muon spin rotation (TF-muSR) exhibits an activated temperature dependence at low temperatures, consistent with a nonzero gap for quasiparticle excitations. In contrast, Meissner-state radiofrequency (rf) inductive measurements of the penetration d

R. F. Rodriguez, I. Santamaria-Holek

The dynamics of temperature fluctuations of a gas of Brownian particles in local equilibrium with a nonequilibrium heat bath, are described using an approach consistent with Boltzmann-Gibbs statistics (BG). We use mesoscopic nonequilibrium thermodynamics (MNET) to derive a Fokker-Planck equation for the probability distribution in phase space including the l

N. Arcozzi, R. Rochberg, E. Sawyer

We characterize the Carleson measures for the Drury-Arveson Hardy space and other Hilbert spaces of analytic functions of several complex variables. This provides sharp estimates for Drury&#39;s generalization of Von Neumann&#39;s inequality. The characterization is in terms of a geometric condition, the &#34;split tree condition&#34;, which reflects the non

S. Van Loo, S. A. E. G. Falle, T. W. Hartquist, T. J. T. Moore

To understand the formation of a magnetically dominated molecular cloud out of an atomic cloud, we follow the dynamical evolution of the cloud with a time-dependent axisymmetric magnetohydrodynamic code. A thermally stable warm atomic cloud is initially in static equilibrium with the surrounding hot ionised gas. A shock propagating through the hot medium int

Shishir Nagaraja

As decentralized computing scenarios get ever more popular, unstructured topologies are natural candidates to consider running mix networks upon. We consider mix network topologies where mixes are placed on the nodes of an unstructured network, such as social networks and scale-free random networks. We explore the efficiency and traffic analysis resistance p

A. V. Shutov, R. Kreissig

This article deals with a viscoplastic material model of overstress type. The model is based on a multiplicative decomposition of the deformation gradient into elastic and inelastic part. An additional multiplicative decomposition of inelastic part is used to describe a nonlinear kinematic hardening of Armstrong-Frederick type. Two implicit time-stepping met

Felix Fernandez-Alonso, F. Javier Bermejo, Carlos Cabrillo, Raouf O. Loutfy

The effects of confining molecular hydrogen within carbon nanohorns are studied via high-resolution quasielastic and inelastic neutron spectroscopies. Both sets of data are remarkably different from those obtained in bulk samples in the liquid and crystalline states. At temperatures where bulk hydrogen is liquid, the spectra of the confined sample show an el

A. Lavagno, A. M. Scarfone, P. Narayana Swamy

Starting from the basic-exponential, a q-deformed version of the exponential function established in the framework of the basic-hypergeometric series, we present a possible formulation of a generalized statistical mechanics. In a q-nonuniform lattice we introduce the basic-entropy related to the basic-exponential by means of a q-variational principle. Remark

M. Kiffner, M. S. Zubairy, J. Evers, C. H. Keitel

A two-mode single-atom laser is considered, with the aim of generating entanglement in macroscopic light. Two transitions in the four-level gain medium atom independently interact with the two cavity modes, while two other transitions are driven by control laser fields. Atomic relaxation as well as cavity losses are taken into account. We show that this syst

Victor S. L&#39;vov, Anna Pomyalov, Antonino Ferrante, Said Elghobashi

We present an analytical model for the time-developing turbulent boundary layer (TD-TBL) over a flat plate. The model provides explicit formulae for the temporal behavior of the wall-shear stress and both the temporal and spatial distributions of the mean streamwise velocity, the turbulence kinetic energy and Reynolds shear stress. The resulting profiles are

Oliver C. Schnürer, Felix Schulze, Miles Simon

We study the Ricci flow for initial metrics which are C^0 small perturbations of the Euclidean metric on R^n. In the case that this metric is asymptotically Euclidean, we show that a Ricci harmonic map heat flow exists for all times, and converges uniformly to the Euclidean metric as time approaches infinity. In proving this stability result, we introduce a

T. Schneider

The effect of the magnetic field on the critical behavior of Sr0:9La0:1CuO2 is explored in terms of reversible magnetization data. As the correlation length transverse to the magnetic field Hi,applied along the i-axis, cannot grow beyond the limiting magnetic length LHi, related to the average distance between vortex lines, one expects a magnetic field induc

Ernesto S. Loscar, Ezequiel V. Albano

An introductory review on the critical behaviour of some irreversible reaction systems is given. The study of these systems has attracted great attention during the last decades due to, on the one hand, the rich and complex underlying physics, and on the other hand, their relevance for numerous technological applications in heterogeneous catalysis, corrosion

Emmanuel Hallouin, Marc Perret

We determine the -1 Tate cohomology group of the units for principal abelian extensions of type (p^a, p^b) of a number field.

Marieke Postma, Betti Hartmann

We study the spectrum of fermionic modes on cosmic string loops. We find no fermionic zero modes nor massive bound states - this implies that vortons stabilized by fermionic currents do not exist. We have also studied kink-(anti)kink and vortex-(anti)vortex systems and find that all systems that have vanishing net topological charge do not support fermionic

Andre&#39; Martinez, Shu Nakamura, Vania Sordoni

This paper is a continuation of a previous paper by the same authors, where an analytic smoothing effect was proved for long-range type perturbations of the Laplacian $H_0$ on $\re^n$. In this paper, we consider short-range type perturbations $H$ of the Laplacian on $\re^n$, and we characterize the analytic wave front set of the solution to the Schrödinger e

Sandro Wimberger, Donatella Ciampini, Oliver Morsch, Riccardo Mannella

Quantum tunnelling from a tilted, but otherwise periodic potential is studied. Our theoretical and experimental results show that, by controlling the system&#39;s parameters, we can engineer the escape rate of a Bose-Einstein condensate to an exceptional degree. Possible applications of this atom-optics realization of the open Wannier-Stark system are discus

Paweł Sztonyk

We prove that bounded harmonic functions of anisotropic fractional Laplacians are Hölder continuous under mild regularity assumptions on the corresponding Lévy measure. Under some stronger assumptions the Green function, Poisson kernel and the harmonic functions are even differentiable of order up to three.

G. Endimioni

Among other things, we prove that the group of automorphisms fixing every normal subgroup of a nilpotent-by-abelian group is nilpotent-by-metabelian. In particular, the group of automorphisms fixing every normal subgroup of a metabelian group is soluble of derived length at most 3. An example shows that this bound cannot be improved.

Kambiz Fathi, John E. Beckman, Claude Carignan, Olivier Hernandez

We present two-dimensional Febry-Perot observations of emission-line distribution and kinematics in nearly spiral galaxies. We have developed and demonstrated the utility of a number of analysis tools which have general applicability, but which we have, so far, applied to only one galaxy (M 74, Fathi et al. 2007). In this galaxy, we have found kinematic sign

X. F. Pan, Aiguo Xu, Guangcai Zhang, Song Jiang

We present an improved lattice Boltzmann model for high-speed compressible flows. The model is composed of a discrete-velocity model by Kataoka and Tsutahara [Phys. Rev. E \textbf{69}, 056702 (2004)] and an appropriate finite-difference scheme combined with an additional dissipation term. With the dissipation term parameters in the model can be flexibly chos

Delphine Lebeugle, Dorothee Colson, Anne Forget, Michel Viret

From an experimental point of view, room temperature ferroelectricity in BiFeO3 is raising many questions. Electric measurements made a long time ago on solid-solutions of BiFeO3 with Pb(Ti,Zr)O3 indicate that a spontaneous electric polarization exists in BiFeO3 below the Curie temperature TC=1143K. Yet in most reported works, the synthesised samples are too

Soeren Asmussen, Pierre Fiorini, Lester Lipsky, Tomasz Rolski

Many processes must complete in the presence of failures. Different systems respond to task failure in different ways. The system may resume a failed task from the failure point (or a saved checkpoint shortly before the failure point), it may give up on the task and select a replacement task from the ready queue, or it may restart the task. The behavior of s

Juergen Herzog, Xinxian Zheng

We compute the Hilbert coefficients of a graded module with pure resolution and discuss lower and upper bounds for these coefficients for arbitrary graded modules.

Hiroki Takesue, Sae Woo Nam, Qiang Zhang, Robert H. Hadfield

Quantum key distribution (QKD) offers an unconditionally secure means of communication based on the laws of quantum mechanics. Currently, a major challenge is to achieve a QKD system with a 40 dB channel loss, which is required if we are to realize global scale QKD networks using communication satellites. Here we report the first QKD experiment in which secu

D. Gerace, L. C. Andreani

A theoretical description of radiation-matter coupling for semiconductor-based photonic crystal slabs is presented, in which quantum wells are embedded within the waveguide core layer. A full quantum theory is developed, by quantizing both the electromagnetic field with a spatial modulation of the refractive index and the exciton center of mass field in a pe

L. C. Andreani, D. Gerace

According to a recent proposal [S. Takayama et al., Appl. Phys. Lett. 87, 061107 (2005)], the triangular lattice of triangular air holes may allow to achieve a complete photonic band gap in two-dimensional photonic crystal slabs. In this work we present a systematic theoretical study of this photonic lattice in a high-index membrane, and a comparison with th

Yuxia Luan, Oliver Lieleg, Bernd Wagner, Andreas R. Bausch

Cells make use of semi-flexible biopolymers such as actin or intermediate filaments to control their local viscoelastic response by dynamically adjusting the concentration and type of cross-linker molecules. The microstructure of the resulting networks mainly determines their mechanical properties. It remains an important challenge to relate structural trans

Jacques Moret-Bailly

The rings observed around supernova remnant 1987A are emitted by a plasma mainly made of ionized and neutral hydrogen atoms. With a density of 10 power 10 atoms per cubic metre, and at least a dimension of plasma of 0.01 light-year, the column density is 10 power 24 atoms per square metre, much more than needed for an optically thick gas at Lyman frequencies

Oliver Lieleg, Andreas R. Bausch

The macromechanical properties of purely bundled in vitro actin networks are not only determined by the micromechanical properties of individual bundles but also by molecular unbinding events of the actin binding protein (ABP) fascin. Under high mechanical load the network elasticity depends on the forced unbinding of individual ABPs in a rate dependent mann

I. G. Usoskin, S. K. Solanki, G. A. Kovaltsov

Using a reconstruction of sunspot numbers stretching over multiple millennia, we analyze the statistics of the occurrence of grand minima and maxima and set new observational constraints on long-term solar and stellar dynamo models. We present an updated reconstruction of sunspot number over multiple millennia, from $^{14}$C data by means of a physics-based

Takaya Nozawa, Takashi Kozasa, Asao Habe, Eli Dwek

We investigate the evolution of dust that formed at Population III supernova (SN) explosions and its processing through the collisions with the reverse shocks resulting from the interaction of the SN ejecta with the ambient medium. In particular, we investigate the transport of the shocked dust within the SN remnant (SNR), and its effect on the chemical comp

S. Fiebig, C. M. Aegerter, W. Bührer, M. Störzer

Although conservation of energy is fundamental in physics, its principles seem to be violated in the field of wave propagation in turbid media by the energy enhancement of the coherent backscattering cone. In this letter we present experimental data which show that the energy enhancement of the cone is balanced by an energy cutback at all scattering angles.

Viliam Pazma, Julius Vanko

We present the very simple model of a particle detector and the proposal for the calculation of the average value of the time of arrival.

G. G. Barnafoldi, P. Levai, B. Lukacs

The electro-magnetic and particle radiation detected from the direction of Cygnus X3 raise the question of the existence of special long-lived, neutral particles. We investigate the origin of these particles in a special approach: the source object may contain compactified extra dimension and these particles are messengers of this state. We describe hyperon

M. Patra, K. De, S. Majumdar, S. Giri

The exchange bias (EB) in LaMn_{0.7}Fe_{0.3}O_3 is observed by the negative shift and training effect of the hysteresis loops, while the sample was cooled in external magnetic field. The analysis of cooling field dependence of EB gives the size of the ferromagnetic (FM) cluster ~ 25 Angstrom, where the magnetic anisotropy of FM cluster is found two order of

Dongho Chae

We consider possible generation of singularities of a vector field transported by diffeomorphisms with derivatives of uniformly bounded determinants. A particular case of volume preserving diffeomrphism is the most important, since it has direct applications to the incompressible, inviscid hydrodynamics. We find relations between the directions of the vector

Naoki Yasuda, Masataka Fukugita, Donald P. Schneider

Galactic extinction is tested using galaxy number counts at low Galactic latitude obtained from five band photometry of the Sloan Digital Sky Survey. The spatial variation of galaxy number counts for low extinction regions of $E(B-V) < 0.15$ is consistent with the all-sky reddening map of Schlegel, Finkbeiner, & Davis (1998) and the standard extinction law.

S. Kabuki, R. Enomoto, CANGAROO-III collaboration

We have observed the giant radio galaxy Centaurus A and the globular cluster $ω$ Centauri in the TeV energy region using the CANGAROO-III stereoscopic system. The system has been in operation since 2004 withan array of four Imaging Atmospheric Cherenkov Telescopes (IACT) with $\sim$100-m spacings. The observations were carried out in March and April 2004. In

Curtis Horn, Heidi Fearn

In this paper we examine the detailed theory of the American football in flight, with spin and air resistance included. We find the theory has much in common with the theory of a gyroscope and also rocket trajectory with a misaligned thruster. Unfortunately most of the air resistance data, for rocketry and ballistics, is for speeds of Mach 1 or higher, where

Will McElgin

The continuation of the Liouville conformal field theory to c<=1 is considered. The viability of an interpretation involving a timelike boson which is the conformal factor for two-dimensional asymptotically de Sitter geometries is examined. The conformal bootstrap leads to a three-point function with a unique analytic factor which is the same as that which a

Myungseok Yoon, Jihye Ha, Wontae Kim

Based on the generalized uncertainty principle, we study the entropy of a four-dimensional black hole by counting degrees of freedom near the horizon and obtain the (finite) entropy proportional to the surface area at the horizon without a cutoff introduced in the conventional brick-wall method.

S. B. Kozitskiy

The multiple scale expansion method is used to derive amplitude equations for a system with thermohaline convection in the neighborhood of Hopf and Taylor bifurcation points and at the double zero point of the dispersion relation. A complex Ginzburg-Landau equation, a Newell-Whitehead-type equation, and an equation of the $ϕ^4$ type, respectively, were obtai

Alexey Goldin, Valery Makarov

Taking advantage of an improved genetic optimization algorithm for fitting unconstrained Kepler orbits to the Hipparcos intermediate astrometric data, we obtain additional orbital solutions for 81 Hipparcos stars with previous stochastic (failed) solutions. The sample includes astrophysically interesting objects, including the old disk wide binary HIP 754, t

A. V. Kitaev, N. S. Witte

A spectral average which generalises the local spacing distribution of the eigenvalues of random $ N\times N $ hermitian matrices in the bulk of their spectrum as $ N\to\infty $ is known to be a $τ$-function of the fifth Painlevé system. This $τ$-function, $ τ(s) $, has generic parameters and is transcendental but is characterised by particular boundary cond

Jean-Francois Bony, Dietrich Hafner

We describe an expansion of the solution of the wave equation in the De Sitter - Schwarzschild metric in terms of resonances. The main term in the expansion is due to a zero resonance. The error term decays polynomially if we permit a logarithmic derivative loss in the angular directions and exponentially if we permit an small derivative loss in the angular

Paola Cappellaro, Chandrasekhar Ramanathan, David G. Cory

Transport of quantum information in linear spin chains has been the subject of much theoretical work. Experimental studies by nuclear spin systems in solid-state by NMR (a natural implementation of such models) is complicated since the dipolar Hamiltonian is not solely comprised of nearest-neighbor XY-Heisenberg couplings. We present here a similarity transf

A. Moosavi, M. Rauscher, S. Dietrich

We investigate the dynamics of nanoscale droplets in the vicinity of chemical steps which separate parts of a substrate with different wettabilities. Due to long-ranged dispersion forces, nanodroplets positioned on one side of the step perceive the different character of the other side even at some distances from the step, leading to a dynamic response. The