December 2008 arXiv papers — page 18
Showing 1,701–1,800 of 5,096 papers
Jacques C. Hurtubise, Michael K. Murray
This paper considers the links between the geometry of the various flag manifolds of loop groups and bundles over families of rational curves. Aa an application, a stability result for the moduli on a rational ruled surface of G-bundles with additional flag structure along a line is proven for any reductive group; this gives the corresponding stability state
Lerothodi L. Leeuw, E. Ian Robson
Deep submillimeter (submm) continuum imaging observations of the starburst galaxy M82 are presented at 350, 450, 750 and 850 micron wavelengths, that were undertaken with the Submillimetre Common-User Bolometer Array (SCUBA) on the James Clerk Maxwell Telescope in Hawaii. The presented maps include a co-addition of submm data mined from the SCUBA Data Archiv
Neerav Kharche, Seongmin Kim, Timothy B. Boykin, Gerhard Klimeck
(111) Silicon quantum wells have been studied extensively, yet no convincing explanation exists for the experimentally observed breaking of 6 fold valley degeneracy into 2 and 4 fold degeneracies. Here, systematic sp3d5s* tight-binding and effective mass calculations are presented to show that a typical miscut modulates the energy levels which leads to break
Sam Payne, Elina Robeva
We present a Monte Carlo algorithm for efficiently finding near optimal moves and bids in the game of Bidding Hex. The algorithm is based on the recent solution of Random-Turn Hex by Peres, Schramm, Sheffield, and Wilson together with Richman's work connecting random-turn games to bidding games.
Microwave frequency modulation in continuous-wave far-infrared ESR utilizing a quasioptical reflection bridge
cond-mat.str-elBalint Nafradi, Richard Gaal, Titusz Feher, Laszlo Forro
We report the development of the frequency-modulation (FM) method for measuring electron spin resonance (ESR) absorption in the 210-420 GHz frequency range. We demonstrate that using a high-frequency ESR spectrometer without resonating microwave components enables us to overcome technical difficulties associated with the FM method due to nonlinear microwave-
V. Heesen, M. Krause, R. Beck, R. -J. Dettmar
We present radio continuum polarimetry observations of the nearby edge-on galaxy NGC 253 which possesses a very bright radio halo. Using the vertical synchrotron emission profiles and the lifetimes of cosmic-ray electrons, we determined the cosmic-ray bulk speed as (300+/-30) km/s, indicating the presence of a galactic wind in this galaxy. The large-scale ma
O. Debarre, A. Iliev, L. Manivel
We prove that the deformations of a smooth complex Fano threefold X with Picard number 1, index 1, and degree 10, are unobstructed. The differential of the period map has two-dimensional kernel. We construct two two-dimensional components of the fiber of the period map through X: one is isomorphic to the variety of conics in X, modulo an involution, another
V. C. Geers, E. F. van Dishoeck, K. M. Pontoppidan, F. Lahuis
PAHs have been detected toward molecular clouds and some young stars with disks, but have not yet been associated with embedded young stars. We present a sensitive mid-IR spectroscopic survey of PAH features toward a sample of low-mass embedded YSOs. The aim is to put constraints on the PAH abundance in the embedded phase of star formation using radiative tr
Sylwia Krupa, Katarzyna Sznajd-Weron
In this paper we examine the role of the so called $c$-parallel updating schemes in relaxation from disordered states to the final ferromagnetic steady state. We investigate two zero-temperature single-spin flip dynamics on a one dimensional lattice of length $L$: inflow (i.e. generalized zero-temperature Glauber dynamics) and outflow opinion dynamics. The v
Leonardo Senatore, Svetlin Tassev, Matias Zaldarriaga
We derive the full set of second-order equations governing the evolution of cosmological perturbations, including the effects of the first-order electron number density perturbations, δ_e. We provide a detailed analysis of the perturbations to the recombination history of the universe and show that a perturbed version of the Peebles effective 3-level atom is
Anna Karpowicz, Krzysztof Szajowski
The aim of the paper is to extend the model of "fishing problem". The simple formulation is following. The angler goes to fishing. He buys fishing ticket for a fixed time. There are two places for fishing at the lake. The fishes are caught according to renewal processes which are different at both places. The fishes' weights and the inter-arrival
Denis Lacroix, Guillaume Hupin
The exact evolution of a system coupled to a complex environment can be described by a stochastic mean-field evolution of the reduced system density. The formalism developed in Ref. [D.Lacroix, Phys. Rev. E77, 041126 (2008)] is illustrated in the Caldeira-Leggett model where a harmonic oscillator is coupled to a bath of harmonic oscillators. Similar exact re
AIRFLY Collaboration, M. Ave
One of the goals of the AIRFLY (AIR FLuorescence Yield) experiment is to measure the absolute fluorescence yield induced by electrons in air to better than 10% precision. We introduce a new technique for measurement of the absolute fluorescence yield of the 337 nm line that has the advantage of reducing the systematic uncertainty due to the detector calibrat
Mehdi Bahrami
Knowledge representation it is an essential section of a Expert Systems, Because in this section we have a framework to establish an expert system then we can modeling and use by this to design an expert system. Many method it is exist for knowledge representation but each method have problems, in this paper we introduce a new method of object oriented by XM
Eric E. Martínez-García, Rosa Amelia González-Lópezlira, Gustavo Bruzual-A.
Azimuthal color (age) gradients across spiral arms are one of the main predictions of density wave theory; gradients are the result of star formation triggering by the spiral waves. In a sample of 13 spiral galaxies of types A and AB, we find that 10 of them present regions that match the theoretical predictions. By comparing the observed gradients with stel
Pantelis A. Damianou
We construct a new symplectic, bi-hamiltonian realization of the KM-system by reducing the corresponding one for the Toda lattice. The bi-hamiltonian pair is constructed using a reduction theorem of Fernandes and Vanhaecke. In this paper we also review the important work of Moser on the Toda and KM-systems.
Deniz Gunduz, Andrea Goldsmith, H. Vincent Poor
A multi-hop two-way relay channel is considered in which all the terminals are equipped with multiple antennas. Assuming independent quasi-static Rayleigh fading channels and channel state information available at the receivers, we characterize the optimal diversity-multiplexing gain tradeoff (DMT) curve for a full-duplex relay terminal. It is shown that the
W. Dimitrov
This paper presents estimations on the possibility of detection of ellipsoidal variations by means of measuring brightness of the star distorted by a close massive planet using Wilson-Devinney method. The problem was already discussed by Phafl et al. (2008) and earlier by Loeb and Gaudi (2003). The effect is well known in the case of binary stars where it ca
Eric Vincent, J. Hammann, Miguel Ocio
The Parisi solution of the mean-field spin glass has been widely accepted and celebrated. Its marginal stability in 3d and its complexity however raised the question of its relevance to real spin glasses. This paper gives a short overview of the important experimental results which could be understood within the mean-field solution. The existence of a true p
Pascal Tixador, Marc Deléglise, Arnaud Badel, Kévin Berger
SMES using high critical temperature superconductors are interesting for high power pulsed sources. Operation at temperatures above 20 K makes cryogenics easier, enhances stability and improves operation as pulsed power source. In the context of a DGA (Delegation Generate pour l'Armement) project, we have designed and constructed a 800 kJ SMES. The coil
Leonardo Giusti, Martin Lüscher
The Banks--Casher relation links the spontaneous breaking of chiral symmetry in QCD to the presence of a non-zero density of quark modes at the low end of the spectrum of the Dirac operator. Spectral observables like the number of modes in a given energy interval are renormalizable and can therefore be computed using the Wilson formulation of lattice QCD eve
J. I. Gillen, W. S. Bakr, A. Peng, P. Unterwaditzer
We demonstrate a novel optical trapping scheme for ultracold atoms. Using a combination of evanescent wave, standing wave, and magnetic potentials we create a deeply 2D Bose-Einstein condensate (BEC) at a few microns from a glass surface. Using techniques such as broadband "white" light to create evanescent and standing waves, we realize a smooth pot
Rouzbeh Allahverdi
There is strong evidence from cosmological data that the universe underwent an epoch of superluminal expansion called inflation. A satisfactory embedding of inflation in fundamental physics has been an outstanding problem at the interface of cosmology and high energy physics. We show how inflation can be realized within the Minimal Supersymmetric Standard Mo
Aleksei V. Chechkin, Irwin M. Zaid, Michael A. Lomholt, Igor M. Sokolov
We consider the effective surface motion of a particle that freely diffuses in the bulk and intermittently binds to that surface. From an exact approach we derive various regimes of the effective surface motion characterized by physical rates for binding/unbinding and the bulk diffusivity. We obtain a transient regime of superdiffusion and, in particular, a
Mariana M. Odashima, K. Capelle, S. B. Trickey
The Lieb-Oxford bound is a constraint upon approximate exchange-correlation functionals. We explore a non-empirical tightening of that bound in both universal and electron-number-dependent form. The test functional is PBE. Regarding both atomization energies (slightly worsened) and bond lengths (slightly bettered), we find the PBE functional to be remarkably
Simulating star formation in molecular cloud cores IV. The role of turbulence and thermodynamics
astro-phR. E. Attwood, S. P. Goodwin, D. Stamatellos, A. P. Whitworth
We perform SPH simulations of the collapse and fragmentation of low-mass cores having different initial levels of turbulence (alpha_turb=0.05,0.10,0.25). We use a new treatment of the energy equation which captures the transport of cooling radiation against opacity due to both dust and gas (including the effects of dust sublimation, molecules, and H^- ions).
Doron Chelouche
We consider a sample of type-I active galactic nuclei (AGN) that were observed by Chandra/HETG and resulted in high signal-to-noise grating spectra, which we study in detail. All objects show signatures for very high ionization outflows. Using a novel scheme to model the physics and spectral signatures of gaseous winds from these objects, we are able to esti
Jimaan Sané, Ard A. Louis, Johan Padding
We apply a hybrid Molecular Dynamics and mesoscopic simulation technique to study the dynamics of two dimensional colloidal discs in confined geometries. We calculate the velocity autocorrelation functions, and observe the predicted $t^{-1}$ long time hydrodynamic tail that characterizes unconfined fluids, as well as more complex oscillating behavior and neg
Luigi Del Debbio, Agostino Patella
We study the center symmetry of SU(N) gauge theories with fermions in the two-index representations, by computing the effective potential of the Polyakov loop in the large-mass expansion on the lattice. In the large-N limit and at non-zero temperature, we find that the center symmetry is Z_N for fermions in the adjoint representation and just Z_2 for fermion
A. V. Zayakin, J. Rafelski
We establish a novel method of obtaining the gauge-invariant bilocal condensate of gluon fields from the solutions of the Dyson--Schwinger equations (DSE) which works in the infrared and ultraviolet limits. We present explicit results for SU(3) case in four dimensions, and compare to other related analytical and lattice results.
A. Arbey
The standard model of cosmology suggests the existence of two components, "dark matter" and "dark energy", which determine the fate of the Universe. Their nature is still under investigation, and no direct proof of their existences has emerged yet. There exist alternative models which reinterpret the cosmological observations, for example by
Gian F. Giudice, Marco Nardecchia, Andrea Romanino
We study the framework of hierarchical soft terms, in which the first two generations of squarks and sleptons are heavier than the rest of the supersymmetric spectrum. This scheme gives distinctive predictions for the pattern of flavor violations, which we compare to the case of nearly degenerate squarks. Experiments in flavor physics have started to probe t
Walter H. Aschbacher
We study the time dependent Hartree equation in the continuum, the semidiscrete, and the fully discrete setting. We prove existence-uniqueness, regularity, and approximation properties for the respective schemes, and set the stage for a controlled numerical computation of delicate nonlinear and nonlocal features of the Hartree dynamics in various physical ap
Denis Lacroix
A Density Matrix Functional theory is constructed semi-empirically for the two-level Lipkin model. This theory, based on natural orbitals and occupation numbers, is shown to provide a good description for the ground state energy of the system as the two-body interaction and particle number vary. The application of Density Matrix Functional theory to the Lipk
On the connection of the generalized nonlinear sigma model with constrained stochastic dynamics
cond-mat.stat-mechFranco Ferrari, Jaroslaw Paturej
The dynamics of a freely jointed chain in the continuous limit is described by a field theory which closely resembles the nonlinear sigma model. The generating functional $Ψ[J]$ of this field theory contains nonholonomic constraints, which are imposed by inserting in the path integral expressing $Ψ[J]$ a suitable product of delta functions. The same procedur
Th. Voigtmann, J. Horbach
We study by molecular dynamics computer simulation a binary soft-sphere mixture that shows a pronounced decoupling of the species' long-time dynamics. Anomalous, power-law-like diffusion of small particles arises, that can be understood as a precursor of a double-transition scenario, combining a glass transition and a separate small-particle localization
Wolfgang Mauerer, Malte Avenhaus, Wolfram Helwig, Christine Silberhorn
Parametric downconversion (PDC) is a technique of ubiquitous experimental significance in the production of non-classical, photon-number correlated twin beams. Standard theory of PDC as a two-mode squeezing process predicts and homodyne measurements observe a thermal photon number distribution per beam. Recent experiments have obtained conflicting distributi
Paolo Bertozzini, Roberto Conti, Wicharn Lewkeeratiyutkul
After recalling in detail some basic definitions on Hilbert C*-bimodules, Morita equivalence and imprimitivity, we discuss a spectral reconstruction theorem for imprimitivity Hilbert C*-bimodules over commutative unital C*-algebras and consider some of its applications in the theory of commutative full C*-categories.
A randomized polynomial-time algorithm for the Spanning Hypertree Problem on 3-uniform hypergraphs
cs.CCSergio Caracciolo, Gregor Masbaum, Alan D. Sokal, Andrea Sportiello
Consider the problem of determining whether there exists a spanning hypertree in a given k-uniform hypergraph. This problem is trivially in P for k=2, and is NP-complete for k>= 4, whereas for k=3, there exists a polynomial-time algorithm based on Lovasz' theory of polymatroid matching. Here we give a completely different, randomized polynomial-time algo
János Kollár
The aim of this note is to discuss resolution theorems that are useful in the study of semi log canonical varieties.
Andre A. Moreira, Jose S. Andrade, Hans J. Herrmann, Joseph O. Indekeu
We investigate topologically biased failure in scale-free networks with degree distribution $P(k) \propto k^{-γ}$. The probability $p$ that an edge remains intact is assumed to depend on the degree $k$ of adjacent nodes $i$ and $j$ through $p_{ij}\propto(k_{i}k_{j})^{-α}$. By varying the exponent $α$, we interpolate between random ($α=0$) and systematic fail
Gwang-Hee Kim, E. M. Chudnovsky
We have shown that the size of the magnetization step due to resonant spin tunneling in a molecular magnet can be strongly affected by sound. The transverse acoustic wave can also generate macroscopic quantum beats of the magnetization during the field sweep.
Shear Flows Driven by the Lorentz Force: An Energy Source for Coronal Mass Ejections and Flares
astro-phWard B. Manchester
Shear flows have been prescribed in numerical models of coronal mass ejections and flares for decades as a way of energizing magnetic fields to erupt. While such shear flows have long been observed in the solar atmosphere, until recently, there was no compelling physical explanation for them. This paper will discuss the discovery that such shear flows are re
K. Vogel, T. Kato, W. P. Schleich, D. Koelle
We consider a fractional Josephson vortex in an infinitely long 0-kappa Josephson junction. A uniform bias current applied to the junction exerts a Lorentz force acting on a vortex. When the bias current becomes equal to the critical (or depinning) current, the Lorentz force tears away an integer fluxon and the junction switches to the resistive state. In th
L. McLerran, K. Redlich, C. Sasaki
The appearance of a new phase of QCD, Quarkyonic Matter in the limit of large number of colors is studied within Nambu-Jona-Lassinio effective chiral model coupled to the Polyakov loop. The interplay of this novel QCD phase with chiral symmetry restoration and color deconfinement is discussed. We find that at vanishing temperature and at large $N_c$, the qua
Denis Duhamel
The finite element computation of structures such as waveguides can lead to heavy computations when the length of the structure is large compared to the wavelength. Such waveguides can in fact be seen as one-dimensional periodic structures. In this paper a simple recursive method is presented to compute the global dynamic stiffness matrix of finite periodic
S. Fournais, A. Kachmar
For a cylindrical superconductor surrounded by a normal material, we discuss transition to the normal phase of stable, locally stable and critical configurations. Associated with those phase transitions, we define critical magnetic fields and we provide a sufficient condition for which those critical fields coincide. In particular, when the conductivity rati
David J Fernandez C, Asish Ganguly
The general solution of the stationary Schrodinger equation for the associated Lame potentials with an arbitrary real energy is found. The supersymmetric partners are generated by employing seeds solutions for factorization energies inside the gaps.
Julien Lavalle
While the PAMELA collaboration has recently confirmed the cosmic ray positron excess, it is interesting to review the effects of dark matter (DM) subhalos on the predicted antimatter signals. We recall that, according to general subhalo properties as inferred from theoretical cosmology, and for DM with constant annihilation cross section, the enhancement can
A. B. Harris, T. Yildirim
Landau theory and symmetry considerations are invoked to give a unified treatment of charge and spin ordering in the mixed valence compound LuFe2O4. In particular, the unusual evolution of charge ordering correlations can be explained by invoking phonon mediated interactions.
Formation of dynamical Schr\"odinger cats in low-dimensional ultracold attractive Bose gases
cond-mat.otherAlexej I. Streltsov, Ofir E. Alon, Lorenz S. Cederbaum
Dynamical Schr\"odinger cats can be formed when a one-dimensional attractive Bose-gas cloud is scattered off a potential barrier. Once formed, these objects are stable in time. The phenomenon and its mechanism -- transformation of kinetic energy to internal energy of the scattered atomic cloud -- are obtained by solving the time-dependent many-boson Schr\"od
N. Benitez, M. Moles, J. A. L. Aguerri, E. Alfaro
In the next years, several cosmological surveys will rely on imaging data to estimate the redshift of galaxies, using traditional filter systems with 4-5 optical broad bands; narrower filters improve the spectral resolution, but strongly reduce the total system throughput. We explore how photometric redshift performance depends on the number of filters n_f,
A. Z. Mekjian
A finite temperature model of strongly correlated nucleons with underlying isospin symmetries is developed. The model can be used to study the role of bound states and Feshbach resonances on the thermal properties of a spin 1/2, isospin 1/2 system of protons and neutrons by varying the proton fraction. An analysis of features associated with a universal ther
Urs Wenger
We have developed an efficient simulation algorithm for strongly interacting relativistic fermions in two-dimensional field theories based on a formulation as a loop gas. The loop models describing the dynamics of the fermions can be mapped to statistical vertex models and our proposal is in fact an efficient simulation algorithm for generic vertex models in
Laurent Amour, Jérémy Faupin, Benoit Grebert, Jean-Claude Guillot
We consider a non-relativistic electron interacting with a classical magnetic field pointing along the $x_3$-axis and with a quantized electromagnetic field. The system is translation invariant in the $x_3$-direction and we consider the reduced Hamiltonian $H(P_3)$ associated with the total momentum $P_3$ along the $x_3$-axis. For a fixed momentum $P_3$ suff
M-A. Suarez, N. Kern, E. Pitard, W. Kob
Using molecular dynamics computer simulations we investigate the aging dynamics of a gel. We start from a fractal structure generated by the DLCA-DEF algorithm, onto which we then impose an interaction potential consisting of a short-range attraction as well as a long-range repulsion. After relaxing the system at T=0, we let it evolve at a fixed finite tempe
Francesco De Bernardis, Rachel Bean, Silvia Galli, Alessandro Melchiorri
Measurements of Baryonic Acoustic Oscillations in galaxy surveys have been recognized as a powerful tool for constraining dark energy. However, this method relies on the knowledge of the size of the acoustic horizon at recombination derived from Cosmic Microwave Background Anisotropy measurements. This estimate is typically derived assuming a standard recomb
A. Bhattacharya, A. Sagari, B. Chakrabarti, S. Mani
A relation between temperature, Fermi momentum and radius of the nucleon has been derived. The percentage increase in radii of the nucleon with temperature and the temperature dependent F$_{2}$ structure function of the nucleon have been investigated. An estimate of the Fermi momentum of the nucleon has been made. The results are found to be in agreement wit
Davide Meloni
In this talk we review the current status of sterile neutrino searches and discuss the potential of future long baseline experiments to study their properties.
Pierre Geneves, Nabil Layaida
This document describes how to use the XML static analyzer in practice. It provides informal documentation for using the XML reasoning solver implementation. The solver allows automated verification of properties that are expressed as logical formulas over trees. A logical formula may for instance express structural constraints or navigation properties (like
Observations of the transiting planet TrES-2 with the AIU Jena telescope in Großschwabhausen
astro-phSt. Raetz, M. Mugrauer, T. O. B. Schmidt, T. Roell
We have started high precision photometric monitoring observations at the AIU Jena observatory in Grossschwabhausen near Jena in fall 2006. We used a 25 cm Cassegrain telescope equipped with a CCD-camera mounted picky-pack on a 90 cm telescope. To test the obtainable photometric precision, we observed stars with known transiting planets. We could recover all
M. Viviani, A. Kievsky, L. Girlanda, L. E. Marcucci
The Kohn variational principle and the hyperspherical harmonics technique are applied to study n-3H elastic scattering at low energies. In this contribution the first results obtained using a non-local realistic interaction derived from the chiral perturbation theory are reported. They are found to be in good agreement with those obtained solving the Faddeev
L. Mazzola, S. Maniscalco, J. Piilo, K. -A. Suominen
We study the exact entanglement dynamics of two qubits in a common structured reservoir. We demonstrate that, for certain classes of entangled states, entanglement sudden death occurs, while for certain initially factorized states, entanglement sudden birth takes place. The backaction of the non-Markovian reservoir is responsible for revivals of entanglement
Guang-Liang Li, Victor O. K. Li
A number has the "collective" property if the number is the greatest lower bound of a bounded, strictly decreasing sequence on the real line. We prove that numbers with the collective property constitute an empty set.
Li-Fang Li, Jian-Yang Zhu
Loop quantum cosmology (LQC) is very powerful to deal with the behavior of early universe. And the effective loop quantum cosmology gives a successful description of the universe in the semiclassical region. We consider the apparent horizon of the Friedmann-Robertson-Walker universe as a thermodynamical system and investigate the thermodynamics of LQC in the
M. Klawunn, L. Santos
Strong 1D lattices usually lead to unconnected two-dimensional gases. The long-range character of the dipole-dipole interactions leads to a novel scenario where non-overlapping gases at different sites may interact significantly. We show that the excitations of non-overlapping condensates in 1D optical lattices acquire a band-like character, being collective
N. V. Kharchenko, P. Berczik, M. I. Petrov, A. E. Piskunov
(abridged) In this paper we derive observed and modelled shape parameters (apparent ellipticity and orientation of the ellipse) of 650 Galactic open clusters identified in the ASCC-2.5 catalogue. We provide the observed shape parameters of Galactic open clusters, computed with the help of a multi-component analysis. For the vast majority of clusters these pa
M. Bridges, F. Feroz, M. P. Hobson, A. N. Lasenby
The form of the primordial power spectrum has the potential to differentiate strongly between competing models of perturbation generation in the early universe and so is of considerable importance. The recent release of five years of WMAP observations have confirmed the general picture of the primordial power spectrum as deviating slightly from scale invaria
Arnaud Debussche, Julien Vovelle
We consider the long-time behavior of the entropy solution of a first-order scalar conservation law on a Riemannian manifold. In the case of the Torus, we show that, under a weak property of genuine non-linearity of the flux, the solution converges to its average value in $L^{p}$, $1\leq p<+\infty$. We give a partial result in the general case.
Markus Bibinger
We focus on estimating the integrated covariance of log-price processes in the presence of market microstructure noise. We construct an efficient unbiased estimator for the quadratic covariation of two Itô processes in the case where high-frequency asynchronous discrete returns under market microstructure noise are observed. This estimator is based on synchr
Hiroyuki Abe, Kang-Sin Choi, Tatsuo Kobayashi, Hiroshi Ohki
We study three generation models in the four-dimensional spacetime, which can be derived from the ten-dimensional N=1 super Yang-Mills theory on the orbifold background with a non-vanishing magnetic flux. We classify the flavor structures and show possible patterns of Yukawa matrices. Some examples of numerical studies are also shown.
E. Brambilla, L. Caspani, O. Jedrkiewicz, L. A. Lugiato
We investigate the spatio-temporal structure of the bi-photon entanglement in parametric down-conversion (PDC) and we demonstrate its non-factorable X-shaped geometry. Such a structure gives access to the ultra-broad bandwidth of PDC, and can be exploited to achieve a bi-photon temporal localization in the femtosecond range. This extreme localization is conn
Li-Fang Li, Jian-Yang Zhu
Wormhole and time machine are very interesting objects in general relativity. However, they need exotic matters which are impossible in classical level to support them. But if we introduce the quantum effects of gravity into the stress-energy tensor, these peculiar objects can be constructed self-consistently. Fortunately, loop quantum cosmology (LQC) has th
Ruben Manvelyan, Eugen Radu, D. H. Tchrakian
We present arguments for the existence of higher dimensional asymptotically AdS non Abelian black holes with a Ricci flat event horizon and analyze their basic properties. Unlike higher dimensional black holes with a curved horizon, of the usual Einstein-Yang-Mills system, these solutions have finite mass-energy. Below some non-zero critical temperature, the
Huayi Chen
We propose a criterion of equidistribution by the differentiability of certain arithmetic invariants. Combined with the slope method and the asymptotic measures, this criterion gives a new "conceptual" proof to equidistribution results originally obtained via the variation principle.
B. Borderie, M. F. Rivet
This review article is focused on the tremendous progress realized during the last fifteen years in the understanding of multifragmentation and its relationship to the liquid-gas phase diagram of nuclei and nuclear matter. The explosion of the whole nucleus, early predicted by Bohr [N. Bohr, Nature 137 (1936) 351], is a very complex and rich subject which co
Relativistically invariant analysis of $Δ$--isobar production in deuteron electrodisintegration: $e^-+d\to e^-+Δ+N:$ general analysis of polarization effects
hep-phG. I. Gakh, E. Tomasi-Gustafsson, A. G. Gakh
The differential cross section and the polarization observables for $Δ$--isobar production in the deuteron electrodisintegration process, $e^-+d\to e^-+Δ+N$, are calculated in a general formalism based on structure functions. The obtained expressions have a general nature, hold for one--photon--exchange, assuming P--invariance of the electromagnetic interact
Ilya L. Shapiro
Quantum gravity is an important and to great extent unsolved problem. There are many different approaches to the quantization of the metric field, both perturbative and non-perturbative. The current situation in the perturbative quantum gravity is characterized by a number of different models, some of them well elaborated but no one perfect nor mathematicall
John Back
We present results from MARS Monte Carlo simulations of the accepted pion and muon yields when a 10 GeV parabolic proton beam interacts with a solid or powdered (50% density) tungsten target for a Neutrino Factory. We compare these yields with the mercury jet target configuration and find that they all give similar rates of pion production. Also provided are
Y. -Z. Chen, Z. -G. Huang, S. -J. Wang, Y. Zhang
In real world, individual rationality varies for the sake of the diversity of people's individuality. In order to investigate how diversity of agent's rationality affects the evolution of cooperation, we introduce the individual rationality proportional to the $β$th power of the each agent's degree. Simulation results on heterogeneous scale-free
J. Bohacik, P. Presnajder
In this article we propose the calculation of the unconditional Wiener measure functional integral with a term of the fourth order in the exponent by an alternative method as in the conventional perturbative approach. In contrast to the conventional perturbation theory, we expand into power series the term linear in the integration variable in the exponent.
A. Isacsson, J. M. Kinaret
We study, numerically and analytically, a model of a one-dimensional array of carbon nanotube resonators in a two-terminal configuration. The system is brought into resonance upon application of an AC-signal superimposed on a DC-bias voltage. When the tubes in the array are close to each other, electrostatic interactions between tubes become important for th
C. Bizdadea, E. M. Cioroianu, S. O. Saliu, S. C. Sararu
An irreducible canonical approach to second-order reducible second-class constraints is given. The procedure is exemplified on gauge-fixed three-forms.
Tom Britton, David Lindenstrand
Epidemic models are always simplifications of real world epidemics. Which real world features to include, and which simplifications to make, depend both on the disease of interest and on the purpose of the modelling. In the present paper we discuss some such purposes for which a \emph{stochastic} model is preferable to a \emph{deterministic} counterpart. The
A. A. Kartamyshev, E. P. Krasnoperov, Yu. D Kuroedov, N. A. Nizhelskiy
A magnetic field relaxation at the center of a pulse-magnetized single-domain Y-Ba-Cu-O superconductor at 78K has been studied. In case of a weak magnetization, the magnetic flux density increases logarithmically and normalized relaxation rate defined as S=-d(lnB)/d(lnt) is negative (S=-0.037). When an external magnetic field magnitude increases, the relaxat
Patrick K. S. Vaudrevange
The compactification of the heterotic string on six-dimensional orbifolds is reviewed. Some important technical aspects of their construction are clarified and new parameters, called generalized discrete torsion, are introduced and related to the torsionless construction. Furthermore, a systematic search for MSSM-like models is performed in the context of Z6
Karsten Henckell, John Rhodes, Benjamin Steinberg
The question of computing the group complexity of finite semigroups and automata was first posed in K. Krohn and J. Rhodes, \textit{Complexity of finite semigroups}, Annals of Mathematics (2) \textbf{88} (1968), 128--160, motivated by the Prime Decomposition Theorem of K. Krohn and J. Rhodes, \textit{Algebraic theory of machines, {I}: {P}rime decomposition t
Controlling the onset of traveling pulses in excitable media by nonlocal spatial coupling and time-delayed feedback
nlin.PSFelix M. Schneider, Eckehard Schoell, Markus A. Dahlem
The onset of pulse propagation is studied in a reaction-diffusion (RD) model with control by augmented transmission capability that is provided either along nonlocal spatial coupling or by time-delayed feedback. We show that traveling pulses occur primarily as solutions to the RD equations while augmented transmission changes excitability. For certain ranges
Marianne Akian, Stephane Gaubert, Alexander Guterman
We investigate different notions of linear independence and of matrix rank that are relevant for max-plus or tropical semirings. The factor rank and tropical rank have already received attention, we compare them with the ranks defined in terms of signed tropical determinants or arising from a notion of linear independence introduced by Gondran and Minoux. To
Three-dimensional Radiative Transfer Modeling of the Polarization of the Sun's Continuous Spectrum
astro-phJ. Trujillo Bueno, N. Shchukina
Here we formulate and solve the 3D radiative transfer problem of the polarization of the solar continuous radiation. Our approach takes into account not only the anisotropy of the continuum radiation, but also the symmetry-breaking effects caused by the horizontal atmospheric inhomogeneities produced by the solar surface convection. Interestingly, our radiat
Eelco Eggen, Marjolein Dijkstra, René van Roij
We explicitly calculate the orientation-dependent second virial coefficient of short charged rods in an electrolytic solvent, assuming the rod-rod interactions to be a pairwise sum of hard-core and segmental screened-Coulomb repulsions. From the parallel and isotropically averaged second virial coefficient, we calculate the effective length and diameter of t
Peter Englmaier, Martin Pohl, Nicolai Bissantz
A complete map of the 3D distribution of molecular (CO) gas was constructed using a realistic dynamical model of the gas flow in the barred potential of the Milky Way. The map shows two prominent spiral arms starting at the bar ends connecting smoothly to the 4-armed spiral pattern observed in the atomic hydrogen gas in the outer Galaxy. Unlike previous atte
C. Bastos, O. Bertolami, N. Dias, J. Prata
One presents a phase-space noncommutative extension of Quantum Cosmology in the context of a Kantowski-Sachs (KS) minisuperspace model. We obtain the Wheeler-DeWitt (WDW) equation for the noncommutative system through the ADM formalism and a suitable Seiberg-Witten map. The resulting WDW equation explicitly depends on the phase-space noncommutative parameter
Petter Holme
Many real-world networks have broad degree distributions. For some systems, this means that the functional significance of the vertices is also broadly distributed, in other cases the vertices are equally significant, but in different ways. One example of the latter case is metabolic networks, where the high-degree vertices -- the currency metabolites -- sup
Quality factor analysis and optimization of digital filtering signal reconstruction for liquid ionization calorimeters
physics.ins-detMarco Delmastro
The Optimal Filtering (OF) reconstruction of the sampled signals from a particle detector such as a liquid ionization calorimeter relies on the knowledge of the normalized pulse shapes. This knowledge is always imprecise, since there are residual differences between the true ionization pulse shapes and the predicted ones, whatever the method used to model or
Charge qubit entanglement via conditional single-electron transfer in an array of quantum dots
cond-mat.mes-hallA. V. Tsukanov
We propose a novel scheme to generate entanglement among quantum-dot-based charge qubits via sequential electron transfer in an auxiliary quantum dot structure whose transport properties are conditioned by qubit states. The transfer protocol requires the utilization of resonant optical pulses combined with an appropriate voltage gate pattern. As an example i
Toshimitsu Takaesu
In this paper, we consider the spectrum of a model in quantum electrodynamics with a spatial cutoff. It is proven that (1) the Hamiltonian is self-adjoint; (2) under the infrared regularity condition, the Hamiltonian has a unique ground state for sufficiently small values of coupling constants. The spectral scattering theory is studied as well and it is show
A. V. Tsukanov
We consider coherent single-electron dynamics in the one-dimensional nanostructure under resonant electromagnetic pulse. The structure is composed of two deep quantum wells positioned at the edges of structure and separated by a sequence of shallow internal wells. We show that complete electron transfer between the states localized in the edge wells through
Superfluidity and Anderson localisation for a weakly interacting Bose gas in a quasiperiodic potential
cond-mat.mes-hallXiaolong Deng, Roberta Citro, Anna Minguzzi, Edmond Orignac
Using exact diagonalisation and Density Matrix Renormalisation group (DMRG) approach, we analyse the transition to a localised state of a weakly interacting quasi-1D Bose gas subjected to a quasiperiodic potential. The analysis is performed by calculating the superfluid fraction, density profile, momentum distribution and visibility for different periodiciti
Automatic Construction of Lightweight Domain Ontologies for Chemical Engineering Risk Management
cs.AIWilson Wong, Wei Liu, Saujoe Liaw, Nicoletta Balliu
The need for domain ontologies in mission critical applications such as risk management and hazard identification is becoming more and more pressing. Most research on ontology learning conducted in the academia remains unrealistic for real-world applications. One of the main problems is the dependence on non-incremental, rare knowledge and textual resources,