November 2009 arXiv papers — page 12
Showing 1,101–1,200 of 5,644 papers
Thermal chaotic mixing: comparison of constant wall temperature and constant heat flux boundary conditions
physics.flu-dynKamal El Omari, Yves Le Guer
In a recent paper (El Omari and Le Guer, IJHMT, 53, 2010) we have investigated mixing and heat transfer enhancement in a mixer composed of two circular rods maintained vertically in a cylindrical tank. The rods and tank can rotate around their revolution axes while their surfaces were maintained at a constant temperature. In the present study we investigate
A lattice based equation of state and $ϕ$ meson production in $\sqrt{s}$=6-200 GeV Pb+Pb and Au+Au collisions
nucl-thVictor Roy, A. K. Chaudhuri
In a boost-invariant hydrodynamic model, we have analyzed $ϕ$ meson production in Pb+Pb and Au+Au collisions, in the centre of mass energy range $\sqrt{s}$= 6-200 GeV. Hydrodynamic evolution is governed by a lattice based equation of state with a confinement-deconfinement {\em cross over} at $T_{co}$=196 MeV. We also look for the threshold energy above which
K. Ishiyama, M. Murata, H. So, K. Takenaga
In a lattice gauge-Higgs unification scenario using a Z_2-orbifolded extra-dimension, we find a new global symmetry in a case of SU(2) bulk gauge symmetry. It is a global symmetry on sites in a fixed point with respect to Z_2-orbifolding, independent of the bulk gauge symmetry. It is shown that the vacuum expectation value of a Z_2-projected Polyakov loop is
Herintsitohaina M. Ratsimbarison
We review standard holographic derivations of the scalar glueball spectra and emphasize computational assumptions which rely strongly on the original AdS/CFT correspondence, and those which are more arbitrary. In the soft-wall model, we show explicitly that the dual of the spectral mass constraint in the Kallen-Lehmann representation of the 2-point scalar gl
Dirac Fermions in Graphene Nanodisk and Graphene Corner: Texture of Vortices with Unusual Winding Number
cond-mat.mes-hallMotohiko Ezawa
We analyze the zero-energy sector of the trigonal zigzag nanodisk and corner based on the Dirac theory of graphene. The zero-energy states are shown to be indexed by the edge momentum and grouped according to the irreducible representation of the trigonal symmetry group $C_{3v}$. Wave functions are explicitly constructed as holomorphic or antiholomorphic fun
Improving the Convergence Properties of the Data Augmentation Algorithm with an Application to Bayesian Mixture Modeling
stat.MEJames P. Hobert, Vivekananda Roy, Christian P. Robert
The reversible Markov chains that drive the data augmentation (DA) and sandwich algorithms define self-adjoint operators whose spectra encode the convergence properties of the algorithms. When the target distribution has uncountable support, as is nearly always the case in practice, it is generally quite difficult to get a handle on these spectra. We show th
Ekin Ozman
Let X^d(N) be the quadratic twist of the modular curve X_0(N) through the Atkin-Lehner involution w_N and a quadratic extension Q(\sqrt{d})/Q. The points of X^d(N)(Q) are precisely the Q(\sqrt{d})-rational points of X_0(N) that are fixed by σcomposition w_N, where σis the generator of Gal(Q(\sqrt{d})/Q).Ellenberg asked the following question: For which d and
Chao Sun, Tom Mullin, Leen van Wijngaarden, Detlef Lohse
Results are reported of an experimental investigation into the motion of a heavy cylinder free to move inside a water-filled drum rotating around a horizontal axis. The cylinder is observed to either co- or, counter intuitively, counter-rotate with respect to the rotating drum. The flow was measured with particle image velocimetry (PIV), and it was found tha
Stability and Unconditional Uniqueness of Solutions for Energy Critical Wave Equations in High Dimensions
math.APAynur Bulut, Magdalena Czubak, Dong Li, Nataša Pavlović
In this paper we establish a complete local theory for the energy-critical nonlinear wave equation (NLW) in high dimensions ${\mathbb R} \times {\mathbb R}^d$ with $d \geq 6$. We prove the stability of solutions under the weak condition that the perturbation of the linear flow is small in certain space-time norms. As a by-product of our stability analysis, w
Akira Ishii, Kazushi Ueda
We construct a full strong exceptional collection consisting of line bundles on any two-dimensional smooth toric weak Fano stack. The total endomorphism algebra of the resulting collection is isomorphic to the path algebra of a quiver with relations associated with a dimer model and a perfect matching on it.
Joan A. Vaccaro
An increasing number of experiments at the Belle, BNL, CERN, DAΦNE and SLAC accelerators are confirming the violation of time reversal invariance (T). The violation signifies a fundamental asymmetry between the past and future and calls for a major shift in the way we think about time. Here we show that processes which violate T symmetry induce destructive i
C. -W. Chou, D. B. Hume, J. C. J. Koelemeij, D. J. Wineland
We have constructed an optical clock with a fractional frequency inaccuracy of 8.6e-18, based on quantum logic spectroscopy of an Al+ ion. A simultaneously trapped Mg+ ion serves to sympathetically laser-cool the Al+ ion and detect its quantum state. The frequency of the 1S0->3P0 clock transition is compared to that of a previously constructed Al+ optical cl
Duncan Forbes, Lee Spitler, William Harris, Jeremy Bailin
Here we present HST/ACS imaging, in the B and I bands, of the edge-on Sb/Sc galaxy NGC 5170. Excluding the central disk region region, we detect a 142 objects with colours and sizes typical of globular clusters (GCs). Our main result is the discovery of a `blue tilt' (a mass-metallicity relation), at the 3sigma level, in the metal-poor GC subpopulation o
Roberto Imbuzeiro Oliveira
We study random k-lifts of large, but otherwise arbitrary graphs G. We prove that, with high probability, all eigenvalues of the adjacency matrix of the lift that are not eigenvalues of G are of the order (D ln (kn))^{1/2}, where D is the maximum degree of G. Similarly, and also with high probability, the "new" eigenvalues of the Laplacian of the lif
Sylvaine Turck-Chieze
The symposium has shown the dynamism of this rapidly evolving discipline. I shall concentrate here on some highlights and some complementary informations. I conclude on open questions with some perspectives on solar & stellar activity and related planets.
Testing Yukawa-unified SUSY during year 1 of LHC: the role of multiple b-jets, dileptons and missing E_T
hep-phHoward Baer, Sabine Kraml, Andre Lessa, Sezen Sekmen
We examine the prospects for testing SO(10) Yukawa-unified supersymmetric models during the first year of LHC running at \sqrt{s}= 7 TeV, assuming integrated luminosity values of 0.1 to 1 fb^-1. We consider two cases: the Higgs splitting (HS) and the D-term splitting (DR3) models. Each generically predicts light gluinos and heavy squarks, with an inverted sc
Three and two-hadron correlations in \sqrt{s_{NN}}=200 GeV proton-proton and nucleus-nucleus collisions
nucl-thAlejandro Ayala, Jamal Jalilian-Marian, J. Magnin, Antonio Ortiz
We compare the azimuthal correlations arising from three and two hadron production in high energy proton-proton and nucleus-nucleus collisions at \sqrt{s_{NN}}=200 GeV, using the leading order matrix elements for two-to-three and two-to-two parton-processes in perturbative QCD. We first compute the two and three hadron production cross sections in mid-rapidi
Dmitry Pelinovsky
Excited states are stationary localized solutions of the Gross--Pitaevskii equation with a harmonic potential and a repulsive nonlinear term that have zeros on a real axis. Existence and asymptotic properties of excited states are considered in the semi-classical (Thomas-Fermi) limit. Using the method of Lyapunov--Schmidt reductions and the known properties
O. Cata
Conventional methods to determine non-perturbative parameters in QCD, such as the different variants of QCD sum rules or the minimal hadronic approximation, combine a certain degree of matching to QCD with inputs from hadronic parameters. The latter introduce systematic errors difficult to quantify. In this paper I will apply a method based on rational appro
K. G. Libbrecht
We review several aspects of aerodynamics that affect the growth, morphology, and symmetry of snow crystals. We derive quantitative estimates for aerodynamical forces that orient falling snow crystals, estimate how air flow around snow crystals affects their growth rates (the ventilation effect), and examine how the combination of orientation and growth modi
Quantum algorithms to solve the hidden shift problem for quadratics and for functions of large Gowers norm
quant-phMartin Roetteler
Most quantum algorithms that give an exponential speedup over classical algorithms exploit the Fourier transform in some way. In Shor's algorithm, sampling from the quantum Fourier spectrum is used to discover periodicity of the modular exponentiation function. In a generalization of this idea, quantum Fourier sampling can be used to discover hidden subg
L. Ghezzi, K. Cunha, F. X. de Araújo, V. V. Smith
The study of chemical abundances in stars with planets is an important ingredient for the models of formation and evolution of planetary systems. In order to determine accurate abundances, it is crucial to have a reliable set of atmospheric parameters. In this work, we describe the homogeneous determination of effective temperatures, surface gravities and ir
Emily M. Levesque
Red supergiants (RSGs) are an evolved He-burning phase in the lifetimes of moderately high mass (10 - 25 solar mass) stars. The physical properties of these stars mark them as an important and extreme stage of massive stellar evolution, but determining these properties has been a struggle for many years. The cool extended atmospheres of RSGs place them in an
Alexander A. Lukyanov
An anisotropic equation of state is proposed for accurate extrapolation of high-pressure shock Hugoniot states to other thermodynamics states for shocked single crystals and polycrystalline alloys. The proposed equation of state represents mathematical and physical generalization of the Mie-Grüneisen equation of state for isotropic material and reduces to th
James W. Cronin
We report on the observations of cosmic rays with energies > 1.0 EeV from Jan 2004 to April 2009 by the Pierre Auger Observatory. During this period the Observatory has grown from about 300 surface detectors to about 1600 upon its completion in November 2008. The 1600 surface detectors are overlooked by 24 fluorescence telescopes. We report on measurements o
Incommensurate itinerant antiferromagnetic excitations and spin resonance in the FeTe$_{0.6}$Se$_{0.4}$ superconductor
cond-mat.supr-conD. N. Argyriou, A. Hiess, A. Akbari, I. Eremin
We report on inelastic neutron scattering measurements that find incommensurate itinerant like magnetic excitations in the normal state of superconducting FeTe$_{0.6}$Se$_{0.4}$ (\Tc=14K) at wave-vector $\mathbf{Q}_{inc}=(1/2\pmε,1/2\mpε)$ with $ε$=0.09(1). In the superconducting state only the lower energy part of the spectrum shows significant changes by t
Matthew B. Hastings, Spyridon Michalakis
We consider two-dimensional Hamiltonians on a torus with finite range, finite strength interactions and a unique ground state with a non-vanishing spectral gap, and a conserved local charge, as defined precisely in the text. Using the local charge operators, we introduce a boundary magnetic flux in the horizontal and vertical direction and evolve the ground
Wojciech Broniowski, Sasa Prelovsek, Luka Santelj, Enrique Ruiz Arriola
We analyze the equal-time Bethe-Salpeter quark wave function of the pion obtained from a quenched lattice QCD calculation with delocalized quark interpolators. We find that the result agrees remarkably well with the predictions of the Nambu--Jona-Lasinio model in all channels. We choose the quenched lattice QCD, since it is closer to the large-Nc limit of th
Abdellatif Zaidi, Shiva Prasad Kotagiri, J. Nicholas Laneman, Luc Vandendorpe
We consider a three-terminal state-dependent relay channel with the channel state noncausally available at only the relay. Such a model may be useful for designing cooperative wireless networks with some terminals equipped with cognition capabilities, i.e., the relay in our setup. In the discrete memoryless (DM) case, we establish lower and upper bounds on c
Yan Guo, Ian Tice
We study the equations obtained from linearizing the compressible Navier-Stokes equations around a steady-state profile with a heavier fluid lying above a lighter fluid along a planar interface, i.e. a Rayleigh-Taylor instability. We consider the equations with or without surface tension, with the viscosity allowed to depend on the density, and in both perio
Vladimir V. Kisil
The purpose of this paper is to articulate an observation that many interesting type of wavelets (or coherent states) arise from group representations which are not square integrable or vacuum vectors which are not admissible. This extends an applicability of the popular wavelets construction to classic examples like the Hardy space. Keywords: Wavelets, cohe
L C Garcia de Andrade
Recently Shukurov et al [Phys Rev \textbf{E} (2008)] presented a numerical solution of a Moebius strip dynamo flow, to investigate its use in modelling dynamo flows in Perm torus of liquid sodium dynamo experiments. Here, by analogy one presents an electric dynamo on a twisted torus or Klein bottle topology. An exact solution in the form of flat Klein bottle
M. -O. Hongler, R. Filliger, Ph. Blanchard
We analytically discuss a multiplicative noise generalization of the Kuramoto-Sakaguchi dynamics for an assembly of globally coupled phase oscillators. In the mean field limit, the resulting class of invariant measures coincides with a generalized, two parameter family of angular von Mises probability distributions which is governed by the exit law from the
A. Alkin, E. Martynov, V. Pauk, E. Romanets
High energy inclusive hadron production in the central kinematical region is analyzed within the models of unitarized pomeron. It is shown that the sum of multipomeron exchanges with intercept $α_P(0)>1$ reproduce qualitatively contribution of the triple pole (at $t=0$) pomeron to inclusive cross section. Basing on this analogy we then suggest a general form
Forward-backward multiplicity fluctuations in heavy nuclei collisions in the wounded nucleon model
hep-phAdam Bzdak, Krzysztof Wozniak
We use the wounded nucleon model to study the forward-backward multiplicity fluctuations measured by the PHOBOS Collaboration in Au+Au collisions at sqrt(s_NN)=200 GeV. The enhancement of forward-backward fluctuations in Au+Au collisions with respect to the elementary p+p interactions is in this model explained by the asymmetric shape of the pseudorapidity d
VERITAS Collaboration, V. A. Acciari, E. Aliu, T. Arlen
We report the detection of very-high-energy (VHE) gamma-ray emission from supernova remnant (SNR) G106.3+2.7. Observations performed in 2008 with the VERITAS atmospheric Cherenkov gamma-ray telescope resolve extended emission overlapping the elongated radio SNR. The 7.3 sigma (pre-trials) detection has a full angular extent of roughly 0.6deg by 0.4deg. Most
Sergio Da Silva, Kalle Karu
The Oda's Strong Factorization Conjecture states that a proper birational map between smooth toric varieties can be decomposed as a sequence of smooth toric blowups followed by a sequence of smooth toric blowdowns. This article describes an algorithm that conjecturally constructs such a decomposition. Several reductions and simplifications of the algorit
A. Aiello, M. Merano, J. P. Woerdman
We report a unified representation of the spatial and angular Goos-Hanchen and Imbert-Fedorov shifts that occur when a light beam reflects from a plane interface. We thus reveal the dual nature of spatial and angular shifts in optical beam reflection. In the Goos-Hanchen case we show theoretically and experimentally that this unification naturally arises in
Cesar Hernandez-Velez, Gelasio Salazar, Robin Thomas
We show that every sufficiently large plane triangulation has a large collection of nested cycles that either are pairwise disjoint, or pairwise intersect in exactly one vertex, or pairwise intersect in exactly two vertices. We apply this result to show that for each fixed positive integer $k$, there are only finitely many $k$-crossing-critical simple graphs
Nicholas Guttenberg, Nigel Goldenfeld
We present a simple model of the emergence of the division of labor and the development of a system of resource subsidy from an agent-based model of directed resource production with variable degrees of trust between the agents. The model has three distinct phases, corresponding to different forms of societal organization: disconnected (independent agents),
M. Heydari-Malayeri
On the occasion of the International Year of Astronomy (IYA2009), we present a new interactive dictionary of astronomy and astrophysics, which contains about 7000 entries. This interdisciplinary and multicultural work is intended for professional and amateur astronomers, university students in astrophysics, as well as terminologists and linguists. A new appr
Max C. Lemme
This paper reviews the current status of graphene transistors as potential supplement to silicon CMOS technology. A short overview of graphene manufacturing and metrology methods is followed by an introduction of macroscopic graphene field effect transistors (FETs). The absence of an energy band gap is shown to result in severe shortcomings for logic applica
Impossibility of large phase shifts via the "giant Kerr effect" with single-photon wavepackets
quant-phJulio Gea-Banacloche
An approximate analytical solution is presented, along with numerical calculations, for a system of two single-photon wavepackets interacting via an ideal, localized Kerr medium. It is shown that, because of spontaneous emission into the initially unoccupied temporal modes, the cross-phase modulation in the Schrodinger picture is very small as long as the sp
Deligne-Mumford compactification of the real multiplication locus and Teichmueller curves in genus three
math.AGMatt Bainbridge, Martin Moeller
In the moduli space M_g of genus g Riemann surfaces, consider the locus RM_O of Riemann surfaces whose Jacobians have real multiplication by the order O in a totally real number field F of degree g. If g = 2 or 3, we compute the closure of RM_O in the Deligne-Mumford compactification of M_g and the closure of the locus of eigenforms over RM_O in the Deligne-
A. V. Lebedev G. B. Lesovik, G. Blatter
We analyze the statistics of the electromagnetic radiation emitted from electrons pushed through a quantum point contact. We consider a setup implemented in a two-dimenional electron gas (2DEG) where the radiation manifests itself in terms of 2D plasmons emitted from electrons scattered at the point contact. The bosonic statistics of the plasmons competes wi
Christophe Dupont
Let $f$ be an holomorphic endomorphism of $\mathbb{C}\mathbb{P}^k$. We construct by using coding techniques a class of ergodic measures as limits of non-uniform probability measures on preimages of points. We show that they have large metric entropy, close to $\log d^k$. We establish for them strong stochastic properties and prove the positivity of their Lya
Convergence of perturbation series for renormalization constants in Kraichnan model with "frozen" velocity field
cond-mat.stat-mechM. V. Komarova, I. S. Kremnev, M. Yu Nalimov
Instanton was found for Kraichnan model with 'frozen' velocity field. Large order asymptotic of quantum-field perturbation expansion for renormalization constant $Z_ν$ was investigated. It was shown that this expansion is convergent one. The radius of convergence was calculated.
Arash Yavari
In this paper we formulate a geometric theory of the mechanics of growing solids. Bulk growth is modeled by a material manifold with an evolving metric. Time dependence of metric represents the evolution of the stress-free (natural) configuration of the body in response to changes in mass density and "shape". We show that time dependency of material
J. Trujillo Bueno
This paper presents an overview of the radiative transfer problem of calculating the spectral line intensity and polarization that emerges from a (generally magnetized) astrophysical plasma composed of atoms and molecules whose excitation state is significantly influenced by radiative transitions produced by an anisotropic radiation field. The numerical solu
Anosh Joseph, Mark Trodden
We study the scattering of noncommutative vortices, based on the noncommutative field theory developed in [Phys. Rev. D 75, 045009 (2007)], as a way to understand the interaction of cosmic strings. In the center-of-mass frame, the effects of noncommutativity vanish, and therefore the reconnection of cosmic strings occurs in an identical manner to the commuta
L. A. Fernandez, V. Martin-Mayor, G. Parisi, B. Seoane
We present a mean field model for spin glasses with a natural notion of distance built in, namely, the Edwards-Anderson model on the diluted D-dimensional unit hypercube in the limit of large D. We show that finite D effects are strongly dependent on the connectivity, being much smaller for a fixed coordination number. We solve the non trivial problem of gen
Paul A. Schweitzer
Every open manifold L of dimension greater than one has complete Riemannian metrics g with bounded geometry such that (L,g) is not quasi-isometric to a leaf of a codimension one foliation of a closed manifold. Hence no conditions on the local geometry of (L,g) suffice to make it quasi-isometric to a leaf of such a foliation. We introduce the `bounded homolog
Robert W. Johnson
The continuous wavelet transform is adapted to account for signal truncation through renormalization and by modifying the shape of the analyzing window. Comparison is made of the instant and integrated wavelet power with previous algorithms. The edge adapted and renormalized admissible wavelet transforms are used to estimate the level of solar magnetic activ
Alexey Pak, Mikhail Rogal, Matthias Steinhauser
We present next-to-next-to-leading order corrections to the inclusive production of the Higgs bosons at the CERN Large Hadron Collider (LHC) including finite top quark mass effects. Expanding our analytic results for the partonic cross section around the soft limit we find agreement with a very recent publication by Harlander and Ozeren \cite{Harlander:2009m
Quantum dynamics of attractive versus repulsive bosonic Josephson junctions: Bose-Hubbard and full-Hamiltonian results
cond-mat.quant-gasKaspar Sakmann, Alexej I. Streltsov, Ofir E. Alon, Lorenz S. Cederbaum
The quantum dynamics of one-dimensional bosonic Josephson junctions with attractive and repulsive interparticle interactions is studied using the Bose-Hubbard model and by numerically-exact computations of the full many-body Hamiltonian. A symmetry present in the Bose-Hubbard Hamiltonian dictates an equivalence between the evolution in time of attractive and
M. Zamaninasab, A. Eckart, G. Witzel, M. Dovciak
We report on the results of new simulations of near-infrared (NIR) observations of the Sagittarius A* (Sgr A*) counterpart associated with the super-massive black hole at the Galactic Center. The observations have been carried out using the NACO adaptive optics (AO) instrument at the European Southern Observatory's Very Large Telescope and CIAO NIR camer
A. M. Mukhamedzhanov, B. F. Irgaziev, V. Z. Goldberg, Yu. V. Orlov
A general method, which we call the potential $S$-matrix pole method, is developed for obtaining the $S$-matrix pole parameters for bound, virtual and resonant states based on numerical solutions of the Schrödinger equation. This method is well-known for bound states. In this work we generalize it for resonant and virtual states, although the corresponding s
Martin Greiter
The elementary excitations of a state of matter consisting of large collection of interacting particles can be very different from the original particles. In the most interesting examples, the particles effectively decompose into smaller constituent particles, which only carry a fraction of their quantum numbers. When these constituents are free, as in fract
R M L Evans
I review a simple method, recently introduced to convert rheological compliance measurements into frequency-dependent moduli. New experimental data are presented, and the scientific implications of various data conversion methods discussed.
S. D. Zakharov N. C. Thanh
The origin of photodamage of single cells confined in laser tweezers is determined by comparison of action spectra with these recorded for a photoinduced response of cell populations. Triplet-singlet transitions in dissolved oxygen provide a common cause of both phenomena. Such transitions are forbidden in isolated O2 molecules, but occur in solutions due to
Gaël Varoquaux, Sepideh Sadaghiani, Jean Baptiste Poline, Bertrand Thirion
Spatial Independent Component Analysis (ICA) is an increasingly used data-driven method to analyze functional Magnetic Resonance Imaging (fMRI) data. To date, it has been used to extract meaningful patterns without prior information. However, ICA is not robust to mild data variation and remains a parameter-sensitive algorithm. The validity of the extracted p
Two Kazdan-Warner type identities for the renormalized volume coefficients and the Gauss-Bonnet curvatures of a Riemannian metric
math.DGBin Guo, Zheng-Chao Han, Haizhong Li
In this note, we prove two Kazdan-Warner type identities involving $v^{(2k)}$, the renormalized volume coefficients of a Riemannian manifold $(M^n,g)$, and $G_{2r}$, the so-called Gauss-Bonnet curvature, and a conformal Killing vector field on $(M^n,g)$. In the case when the Riemannian manifold is locally conformally flat, $v^{(2k)}=(-2)^{-k}σ_k$, $G_{2r}(g)
A. Bhagwat, X. Viñas, M. Centelles, P. Schuck
The semi-classical Wigner-Kirkwood $\hbar$ expansion method is used to calculate shell corrections for spherical and deformed nuclei. The expansion is carried out up to fourth order in $\hbar$. A systematic study of Wigner-Kirkwood averaged energies is presented as a function of the deformation degrees of freedom. The shell corrections, along with the pairin
Laurent Boue, Peter Harrowell, Smarajit Karmakar, Edan Lerner
Developing a macroscopic theory of elasto-plasticity in amorphous solids calls for (i) identifying the relevant macro state-variables and (ii) discriminating the different time-scales which characterize these variables. In current theories it is assumed that the stress reaches its elasto-plastic steady state value on the same time-scale as the configurationa
Nicolas Castagné, Claude Cadoz, Ali Allaoui, Olivier Michel Tache
GENESIS3 is the new version of the GENESIS software environment for musical creation by means of mass-interaction physics network modeling. It was designed, and developed from scratch, in hindsight of more than 10 years working on and using the previous version. We take the opportunity of this birth to provide in this article (1) an analysis of the peculiari
Marc Louis Maurice François
An ultrasonic measurement of the stiffness tensor of a spruce specimen is made for different moisture content. We show that a known scalar indicator describres correctly the quality of the wood and that the distance from the stiffness tensor to the tetragonal symmetry group describes the quality of the measurements. -- Une mesure ultrasonore du tenseur d'
N. Srinidhi, Saif K. Mohammed, A. Chockalingam, B. Sundar Rajan
Low-complexity near-optimal signal detection in large dimensional communication systems is a challenge. In this paper, we present a reactive tabu search (RTS) algorithm, a heuristic based combinatorial optimization technique, to achieve low-complexity near-maximum likelihood (ML) signal detection in linear vector channels with large dimensions. Two practical
Emmanuel Friot, Alexandre Gintz
In theory, active control could be used to reduce the unwanted noise reflections from surfaces such as a submarine hull or the walls of an anechoic room. In the recent years, a real-time algorithm has been developed to this effect at the Laboratoire de Mécanique et d'Acoustique: the noise scattered by the surface is estimated through linear filtering of
Isabelle Camilier, Laurent Decreusefond
Determinantal and permanental processes are point processes with a correlation function given by a determinant or a permanent. Their atoms exhibit mutual attraction of repulsion, thus these processes are very far from the uncorrelated situation encountered in Poisson models. We establish a quasi-invariance result : we show that if atoms locations are perturb
Kiri Nichol, Alexey Zanin, Renaud Bastien, Elie Wandersman
We fluidize a granular medium through localized stirring and probe the mechanical response of quiescent regions far away from the main flow. In these regions the material behaves like a liquid: high-density probes sink, low-density probes float at the depth given by Archimedes' law, and drag forces on moving probes scale linearly with the velocity. The f
Danilo Royer, Daniel Goncalves
In this paper we show that, for a class of countable graphs, every representation of the associated graph algebra in a separable Hilbert space is unitarily equivalent to a representation obtained via branching systems.
G. Cacciapaglia, S. Rai Choudhury, A. Deandrea, N. Gaur
Little Higgs models are often endowed with a T-parity in order to satisfy electroweak precision tests and give at the same time a stable particle which is a candidate for cold dark matter. This type of models predicts a set of new T-odd fermions in addition to the heavy gauge bosons of the Little Higgs models, which may show interesting signatures at collide
Origin of adiabatic and non-adiabatic spin transfer torques in current-driven magnetic domain wall motion
cond-mat.mes-hallJun-ichiro Kishine, A. S. Ovchinnikov
A consistent theory to describe the correlated dynamics of quantum mechanical itinerant spins and semiclassical local magnetization is given. We consider the itinerant spins as quantum mechanical operators, whereas local moments are considered within classical Lagrangian formalism. By appropriately treating fluctuation space spanned by basis functions, inclu
Jorge A. Rueda, Remo Ruffini, She-Sheng Xue
We address the existence of globally neutral neutron star configurations in contrast with the traditional ones constructed by imposing local neutrality. The equilibrium equations describing this system are the Einstein-Maxwell equations which must be solved self-consistently with the general relativistic Thomas-Fermi equation and $β$-equilibrium condition. T
Vadim E. Levit, Eugen Mandrescu
The independence number of a graph G, denoted by alpha(G), is the cardinality of an independent set of maximum size in G, while mu(G) is the size of a maximum matching in G, i.e., its matching number. G is a Konig-Egervary graph if its order equals alpha(G)+mu(G). In this paper we give a new characterization of Konig-Egervary graphs. We also deduce some prop
Kostas Margellos, John Lygeros
A new framework for formulating reachability problems with competing inputs, nonlinear dynamics and state constraints as optimal control problems is developed. Such reach-avoid problems arise in, among others, the study of safety problems in hybrid systems. Earlier approaches to reach-avoid computations are either restricted to linear systems, or face numeri
Clas Löfwall
An infinite filiform Lie algebra L is residually nilpotent and its graded associated with respect to the lower central series has smallest possible dimension in each degree but is still infinite. This means that gr(L) is of dimension two in degree one and of dimension one in all higher degrees. We prove that if L is solvable, then already [L,L] is abelian. T
J. Koplik, G. Drazer
When particles suspended in a fluid are driven through a regular lattice of cylindrical obstacles, the particle motion is usually not simply in the direction of the force, and in the high Peclet number limit particle trajectories tend to lock along certain lattice directions. By means of molecular dynamics simulations we show that this effect persists in the
Single-photon emission via Raman scattering from the levels with partially resolved hyperfine structure
quant-phV. A. Reshetov, I. V. Yevseyev
The probability of emission of a single photon via Raman scattering of laser pulse on the three-level $Λ$ - type atom in microcavity is studied. The duration of the pulse is considered to be short enough, so that the hyperfine structure of the upper level remains totally unresolved, while that of the lower level is totally resolved. The coherent laser pulse
Chethan Krishnan
In string theory, stacks of D1-branes can expand into intersecting D3-branes. These configurations are called (generalized) BIons. We show how the analogous constructions in M-theory, where M2-branes blow up into calibrated intersections of M5-branes, arise from some of the membrane theories.
Marius Buliga
For the importance of differentiation theorems in metric spaces (starting with Pansu Rademacher type theorem in Carnot groups) and relations with rigidity of embeddings see the section 1.2 in Cheeger and Kleiner paper arXiv:math/0611954 and its bibliographic references. Here we propose another type of differentiation theorem, which does not involve measures.
Pradipta Kumar Mandal, Debnarayan Jana
We demonstrate the non-universal behavior of finite size scaling in (1+1) dimension of a nonlinear discrete growth model involving extended particles in generalized point of view. In particular, we show the violation of the universal nature of the scaling function corresponding to the height fluctuation in (1+1) dimension. The 2nd order moment of the height
P. Zinn-Justin
We describe a new conjecture involving Fully Packed Loop counting which relates recent observations of Thapper to formulae in the Temperley--Lieb model of loops, and how it implies the Razumov--Stroganov conjecture.
A. V. Akindinov, M. M. Chumakov, M. M. Firoozabadi, Yu. T. Kiselev
The differential production cross sections of K^+ and K^- mesons have been measured at the ITEP proton synchrotron in p+Be, p+Cu collisions under lab angle of 10.5^0, respectively, at 1.7 and 2.25, 2.4 GeV beam energies. A detailed comparison of these data with the results of calculations within an appropriate folding model for incoherent primary proton-nucl
M. V. Gromovyi, V. I. Romanenko, L. P. Yatsenko
The theory of stimulated Raman adiabatic passage in a three-level Lambda-scheme of the interaction of an atom or molecule with light, which takes the nonadiabatic processes at the beginning and the end of light pulses into account, is developed.
Contribution of Cross-Correlations to the 21cm Angular Power Spectrum in the Epoch of Reionization
astro-ph.COQian Zheng
Measurement of the 21cm hyperfine transition of neutral hydrogen provides a unique probe of the epoch of reionization and the Dark Ages. Three major mechanisms are believed to dominate the radiation process: emission from neutral hydrogen surrounding the ionized bubbles of first galaxies and/or quasars, emission from neutral hydrogen inside minihalos, and ab
F. Levrier, R. J. Wilman, D. Obreschkow, H. -R. Kloeckner
The S3-Tools are a set of Python-based routines and interfaces whose purpose is to provide user-friendly access to the SKA Simulated Skies (S3) set of simulations, an effort led by the University of Oxford in the framework of the European Union's SKADS program (http://www.skads-eu.org). The databases built from the S3 simulations are hosted by the Oxford
V. Greco, M. Colonna, M. Di Toro, H. H. Wolter
The nuclear symmetry energy at densities above saturation density ($ρ_0\sim 0.16 fm^{-3}$) is poorly constrained theoretically and very few relevant experimental data exist. Its study is possible through Heavy Ion Collisions (HIC) at energies $E/A> 200$ MeV, particularly with beams of neutron-rich radioactive nuclei. The energy range implies that the momentu
Francois Arleo
The QCD phenomenology of prompt photon production from e-p to p-p/p-pbar and A-A collisions is reviewed. The use of prompt photons as a probe of (i) parton distribution functions (in a proton or in nuclei) as well as (ii) fragmentation functions (into photons and hadrons) and their medium-modifications is highlighted.
Magnetic properties and atomic structure of La(2/3)Ca(1/3)MnO(3)-YBa(2)Cu(3)O(7) heterointerfaces
cond-mat.str-elZ. L. Zhang, U. Kaiser, S. Soltan, H. -U. Habermeier
A heterostructure comprised of a 2.7 nm (7 unit-cell) thick layer of the metallic ferromagnet La(2/3)Ca(1/3)MnO(3) and two 50 nm thick layers of the high-temperature superconductor YBa(2)Cu(3)O(7) epitaxially grown on (100) SrTiO3 by pulsed-laser deposition was characterized by magnetization measurements and spherical-aberration-corrected high-resolution tra
Nan Su, Jens O. Andersen, Michael Strickland
The weak-coupling expansion for thermodynamic quantities in thermal field theories is poorly convergent unless the coupling constant is tiny. We discuss the calculation of the free energy for a hot gas of electrons and photons to three-loop order using hard-thermal-loop perturbation theory (HTLpt). We show that the hard-thermal-loop perturbation reorganizati
Pinja Haikka
We present a detailed microscopic derivation for a non-Markovian master equation for a driven two-state system interacting with a general structured reservoir. The master equation is derived using the time-convolutionless projection operator technique in the limit of weak coupling between the two-state quantum system and its environment. We briefly discuss t
Nick Seymour
The current deepest radio surveys detect hundreds of sources per square degree below 0.1mJy. There is a growing consensus that a large fraction of these sources are dominated by star formation although the exact proportion has been debated in the literature. However, the low luminosity of these galaxies at most other wavelengths makes determining the nature
Hyunsoo Min
We study the zero modes of the Abelian Dirac operator in any odd dimension. We use the stereographic projection between a $(2n-1)$ dimensional space and a $(2n-1)$ sphere embedded in a $2n$ dimensional space. It is shown that the Dirac operator with a gauge field of uniform field strengths in $S^{2n-1}$ has symmetries of SU($n$)$\times$U(1) which is a subgro
A. Belavin, V. Belavin
In addition to the ordinary bulk higher equations of motion in the boundary version of the Liouville conformal field theory, an infinite set of relations containing the boundary operators is found. These equations are in one-to-one correspondence with the singular representations of the Virasoro algebra. We comment on the possible applications in the context
Closed-form formulae for the derivatives of trigonometric functions at rational multiples of $π$
math.CADjurdje Cvijović
In this sequel to our recent note it is shown, in a unified manner, by making use of some basic properties of certain special functions, such as the Hurwitz zeta function, Lerch zeta function and Legendre chi function, that the values of all derivatives of four trigonometric functions at rational multiples of $π$ can be expressed in closed form as simple fin
Manfred Herbst, Johannes Walcher
We identify a class of autoequivalences of triangulated categories of singularities associated with Calabi-Yau complete intersections in toric varieties. Elements of this class satisfy relations that are directly linked to the toric data.
Bengt Eliasson, Padma K. Shukla
We present a derivation of the dispersion relation for electrostatic oscillations (ESOs) in a zero temperature quantum plasma. In the latter, degenerate electrons are governed by the Wigner equation, while non-degenerate ions follow the classical fluid equations. The Poisson equation determines the electrostatic wave potential. We consider parameters ranging
The circumstellar disk, envelope, and bi-polar outflow of the Massive Young Stellar Object W33A
astro-ph.SRBen Davies, Stuart L. Lumsden, Melvin G. Hoare, Rene D. Oudmaijer
The Young Stellar Object (YSO) W33A is one of the best known examples of a massive star still in the process of forming. Here we present Gemini North ALTAIR/NIFS laser-guide star adaptive-optics assisted K-band integral-field spectroscopy of W33A and its inner reflection nebula. In our data we make the first detections of a rotationally-flattened outer envel
T. V. Zaqarashvili, M. Carbonell, R. Oliver, J. L. Ballster
Apart from the 11-year solar cycle, another periodicity around 155-160 days was discovered during solar cycle 21 in high energy solar flares, and its presence in sunspot areas and strong magnetic flux has been also reported. This periodicity has an elusive and enigmatic character, since it usually appears only near the maxima of solar cycles, and seems to be