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Arxiv.org
by A Müller; S Schippers; R. A. Phaneuf; A. L. D. Kilcoyne; H. Bräuning; A. S. Schlachter; M. Lu; B. M. McLaughlin
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High-resolution photoionization experiments were carried out using beams of Be-like C$^{2+}$, N$^{3+}$, and O$^{4+}$ ions with roughly equal populations of the $^1$S ground-state and the $^3$P$^o$ manifold of metastable components. The energy scales of the experiments are calibrated with uncertainties of 1 to 10 meV depending on photon energy. Resolving powers beyond 20,000 were reached allowing for the separation of contributions from the individual metastable $^3$P$^o_0$, $^3$P$^o_1$, and...
Source: http://arxiv.org/abs/1203.6533v1
Arxiv.org
by A Müller; S. Schippers; R. A. Phaneuf; S. W. J. Scully.; A. Aguilar; A. M. Covington; I. Álvarez; C Cisneros; E. D. Emmons; M. F. Gharaibeh; G. Hinojosa; A S. Schlachter; B. M. McLaughlin
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Absolute cross sections for the K-shell photoionization of ground-state Li-like carbon [C$^{3+}$(1s$^2$2s $^2$S)] ions were measured by employing the ion-photon merged-beams technique at the Advanced Light Source. The energy ranges 299.8--300.15 eV, 303.29--303.58 eV and 335.61--337.57 eV of the [1s(2s2p)$^3$P]$^2$P, [1s(2s2p)$^1$P]$^2$P and [(1s2s)$^3$S 3p]$^2$P resonances, respectively, were investigated using resolving powers of up to 6000. The autoionization linewidth of the...
Source: http://arxiv.org/abs/1203.5441v1
Arxiv.org
by A. -L. Maire; R. Galicher; A. Boccaletti; P. Baudoz; J. Schneider; K. L. Cahoy; D. M. Stam; W. A. Traub
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Context. High-contrast imaging is currently the only available technique for the study of the thermodynamical and compositional properties of exoplanets in long-period orbits. The SPICES project is a coronagraphic space telescope dedicated to the spectro-polarimetric analysis of gaseous and icy giant planets as well as super-Earths at visible wavelengths. So far, studies for high-contrast imaging instruments have mainly focused on technical feasibility because of the challenging planet/star...
Source: http://arxiv.org/abs/1203.2826v1
Arxiv.org
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Assuming that giant planets are formed in thin protoplanetary discs, a '3D' system can form, provided that the mutual inclination is excited by some dynamical mechanism. Resonant interactions and close planetary encounters are thought to be the primary inclination-excitation mechanisms, resulting in a resonant and non-resonant system, respectively. Here we propose an alternative formation scenario, starting from a system composed of three giant planets in a nearly coplanar configuration. As was...
Source: http://arxiv.org/abs/1203.2955v1
Arxiv.org
by A. -S. Libert; K. Tsiganis
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We study the establishment of three-planet resonances -similar to the Laplace resonance in the Galilean satellites- and their effects on the mutual inclinations of the orbital planes of the planets, assuming that the latter undergo migration in a gaseous disc. In particular, we examine the resonance relations that occur, by varying the physical and initial orbital parameters of the planets (mass, initial semi-major axis and eccentricity) as well as the parameters of the migration forces...
Source: http://arxiv.org/abs/1203.2960v1
Arxiv.org
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We study the dynamics of the 3-D three-body problem of a small body moving under the attractions of a star and a giant planet which orbits the star on a much wider and elliptic orbit. In particular, we focus on the influence of an eccentric orbit of the outer perturber on the dynamics of a small highly inclined inner body. Our analytical study of the secular perturbations relies on the classical octupole hamiltonian expansion (third-order theory in the ratio of the semi-major axes), as...
Source: http://arxiv.org/abs/1203.2849v1
Arxiv.org
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We have calculated the Bardeen-Stephen contribution to the vortex viscosity for uniaxial anisotropic superconductors within the time-dependent Ginzburg-Landau (TDGL) theory. We focus our attention on superconductors with a mismatch of anisotropy of normal and superconducting characteristics. Exact asymptotics for the Bardeen-Stephen contribution have been derived in two limits: the cases of small and large electric field penetration depth (as compared to the coherence length). Also we suggest a...
Source: http://arxiv.org/abs/1203.0459v2
Arxiv.org
by A. A. Bhorkar; T. Javidi; A. C. Snoeren
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This paper reports on the first systematic study of congestion-aware routing algorithms for wireless mesh networks to achieve an improved end-end delay performance. In particular, we compare 802.11 compatible implementations of a set of congestion-aware routing protocols against our implementation of state of the art shortest path routing protocol (SRCR). We implement congestion-aware routing algorithms Backpressure (BP), Enhanced-Backpressure (E-BP) adapted from [1], [2] suitably adjusted for...
Source: http://arxiv.org/abs/1203.4841v1
Arxiv.org
by A. A. Bylinkin; A. A. Rostovtsev
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The shapes of invariant differential cross section for identified pi,K, p and pbar production as function of transverse momentum measured in pp collisions by the PHENIX detector are analyzed. Simultaneous fit of these data to the sum of exponential and power-law terms show significant difference in the exponential term contributions. This effect qualitatively explains the observed shape of the experimental K/pi and p/pi yield ratios measured as function of transverse momentum of produced...
Source: http://arxiv.org/abs/1203.2840v1
Arxiv.org
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We propose a relativistic particle model without Grassmann variables which, being canonically quantized, leads to the Dirac equation. Both $\Gamma$\,-matrices and the relativistic spin tensor are produced through the canonical quantization of the classical variables which parametrize the properly constructed relativistic spin surface. Although there is no mass-shell constraint in our model, our particle's speed cannot exceed the speed of light. The classical dynamics of the model is in...
Source: http://arxiv.org/abs/1107.0273v4
Arxiv.org
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We construct a non-Grassmann spinning-particle model which, by analogy with quantum mechanics, does not admit the notion of a trajectory within the position space. The pseudo-classical character of the model allows us to avoid the inconsistencies arising in the quantum-mechanical interpretation of a one-particle sector of the Dirac equation.
Source: http://arxiv.org/abs/1203.5697v3
Arxiv.org
by A. A. Fernandez-Marin; J. A. Mendez-Bermudez; Victor A. Gopar
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We study the electromagnetic transmission $T$ through one-dimensional (1D) photonic heterostructures whose random layer thicknesses follow a long-tailed distribution --L\'evy-type distribution. Based on recent predictions made for 1D coherent transport with L\'evy-type disorder, we show numerically that for a system of length $L$ (i) the average $ \propto L^\alpha$ for $0
Source: http://arxiv.org/abs/1203.1337v1
Arxiv.org
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Current situation with phenomenological description of high-energy nucleon-nucleon diffractive elastic scattering is reviewed. Comparison of various model predictions with the recent D0 and TOTEM data on the nucleon-nucleon total and differential cross-sections is presented.
Source: http://arxiv.org/abs/1203.6013v2
Arxiv.org
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Two particle collisions close to the horizon of the rotating nonextremal Kerr's and Schwarzschild black holes are analyzed. For the case of multiple collisions it is shown that high energy in the centre of mass frame occurs due to a great relative velocity of two particles and a large Lorentz factor. The dependence of the relative velocity on the distance to horizon is analyzed, the time of movement from the point in the accretion disc to the point of scattering with large energy as well as the...
Source: http://arxiv.org/abs/1203.4952v1
Arxiv.org
by A. A. Grinyuk; H. Jung; G. I. Lykasov; A. V. Lipatov; N. P. Zotov
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We found the parameterization of the unintegrated gluon distribution from the best description of the LHC data on the inclusive spectra of hadrons produced in $pp$ collisions at the mid-rapidity region and small transverse momenta. It is different from the one obtained within perturbative QCD only at low intrinsic transverse momenta $k_t$. The application of this distribution to analysis of the $e-p$ DIS allows us to get the results which do not contradict the H1 and ZEUS data on the structure...
Source: http://arxiv.org/abs/1203.0939v1
Arxiv.org
by A. A. Nucita; F. De Paolis; R. Saxton; A. M. Read
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IGRJ17361-4441 is a hard transient recently observed by the INTEGRAL satellite. The source, close to the center of gravity of the globular cluster NGC 6388, quickly became the target of follow-up observations conducted by the Chandra, Swift/XRT and RXTE observatories. Here, we concentrate in particular on a set of observations conducted by the XMM-Newton satellite during two slews, in order to get the spectral information of the source and search for spectral variations. The spectral parameters...
Source: http://arxiv.org/abs/1203.0965v2
Arxiv.org
by A. A. Shanenko; M. D. Croitoru; A. V. Vagov; V. M. Axt; A. Perali; F. M. Peeters
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Quantum-size oscillations of the basic physical characteristics of a confined fermionic condensate are a well-known phenomenon. Its conventional understanding is based on the single-particle physics, whereby the oscillations follow the size-dependent changes in the single-particle density of states. Here we present a study of a cigar-shaped ultracold superfluid Fermi gas, which demonstrates an important many-body aspect of the quantum-size effects, overlooked previously. The many-body physics...
Source: http://arxiv.org/abs/1203.3325v2
Arxiv.org
by A. A. Zheltukhin
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Nonlinear equations of $p$-branes in $D=(2p+1)$-dimensional Minkowski space are discussed. Presented are new exact solutions for a set of spinning $p$-branes with $p=2,3,...,(D-1)/2$ and the Abelian symmetries $U(1)\times U(1)\times... \times U(1)$ of their shapes.
Source: http://arxiv.org/abs/1203.4783v1
Arxiv.org
by A. Ahadi; Nazli Besharati; E. S. Mahmoodian; M. Mortezaeefar
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For a block design $\cal{D}$, a series of {\sf block intersection graphs} $G_i$, or $i$-{\rm BIG}($\cal{D}$), $i=0, ..., k$ is defined in which the vertices are the blocks of $\cal{D}$, with two vertices adjacent if and only if the corresponding blocks intersect in exactly $i$ elements. A silver graph $G$ is defined with respect to a maximum independent set of $G$, called a {\sf diagonal} of that graph. Let $G$ be $r$-regular and $c$ be a proper $(r + 1)$-coloring of $G$. A vertex $x$ in $G$ is...
Source: http://arxiv.org/abs/1005.4492v3
Arxiv.org
by A. Ahuja; K. Venkateswarlu; P. Venkata Krishna
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Simulation results for Mobile Ad-Hoc Networks (MANETs) are fundamentally governed by the underlying Mobility Model. Thus it is imperative to find whether events functionally dependent on the mobility model 'converge' to well defined functions or constants. This shall ensure the long-run consistency among simulation performed by disparate parties. This paper reviews a work on the discrete Random Waypoint Mobility Model (RWMM), addressing its long run stochastic stability. It is proved that each...
Source: http://arxiv.org/abs/1203.3920v1
Arxiv.org
by A. Alahmadi; R. E. L. Aldred; R. dela Cruz; P. Solé; C. Thomassen
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Upper and lower bounds are derived for the quantity in the title, which is tabulated for modest values of $n$ and $k.$ An application to graphs with many cycles is given.
Source: http://arxiv.org/abs/1203.0728v1
Arxiv.org
by A. Alves; E. Ramirez Barreto; A. G. Dias
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Within the 3-3-1 model framework, we consider the production and decay of fermionic leptoquarks into a striking experimental signature at the LHC: a narrow resonance at the $b$ jet plus same-sign dileptons channel. The data already accumulated by the LHC collaborations may hide a large number of events associated to the production and decay of such exotic quarks, allowing one to investigate large portions of the parameters space of the model. The observation or not of such events would shed...
Source: http://arxiv.org/abs/1203.2342v3
Arxiv.org
by A. Anandkumar; D. Hsu; F. Huang; S. M. Kakade
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We consider unsupervised estimation of mixtures of discrete graphical models, where the class variable corresponding to the mixture components is hidden and each mixture component over the observed variables can have a potentially different Markov graph structure and parameters. We propose a novel approach for estimating the mixture components, and our output is a tree-mixture model which serves as a good approximation to the underlying graphical model mixture. Our method is efficient when the...
Source: http://arxiv.org/abs/1203.0697v2
Arxiv.org
by A. Aret; M. Kraus; M. F. Muratore; M. Borges Fernandes
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The disc formation mechanism of B[e] supergiants is one of the puzzling phenomena in massive star evolution. Rapid stellar rotation seems to play an important role for the non-spherically symmetric mass-loss leading to a high-density disc or ring-like structure of neutral material around these massive and luminous objects. The radial density and temperature structure as well as the kinematics within this high-density material are, however, not well studied. Based on high-resolution optical...
Source: http://arxiv.org/abs/1203.6808v1
Arxiv.org
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Optical observations of the low mass X-ray binary 4U 1735-44 were obtained during 1997-2007 and combined with earlier published observations from 1984-1993 to refine the ephemeris for the system. The linear fit for the time of maximum optical light has the ephemeris HJD = 2445904.0494(90) + [ N x 0.19383222(29)] with a value of chi^2 = 253.5$ for 16 dof and a scatter about phase zero of sigma = 0.061. The new data reconciles the discrepancy between the previous ephemeris and the more recent...
Source: http://arxiv.org/abs/1203.1988v1
Arxiv.org
by A. B. Goncharov; R. Kenyon
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We show that the dimer model on a bipartite graph on a torus gives rise to a quantum integrable system of special type - a cluster integrable system. The phase space of the classical system contains, as an open dense subset, the moduli space of line bundles with connections on the graph. The sum of Hamiltonians is essentially the partition function of the dimer model. Any graph on a torus gives rise to a bipartite graph on the torus. We show that the phase space of the latter has a Lagrangian...
Source: http://arxiv.org/abs/1107.5588v2
Arxiv.org
by A. B. Klimov; C. Munoz; L. L. Sanchez-Soto
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The phase space for a system of $n$ qubits is a discrete grid of $2^{n} \times 2^{n}$ points, whose axes are labeled in terms of the elements of the finite field $\Gal{2^n}$ to endow it with proper geometrical properties. We analyze the representation of graph states in that phase space, showing that these states can be identified with a class of non-singular curves. We provide an algebraic representation of the most relevant quantum operations acting on these states and discuss the advantages...
Source: http://arxiv.org/abs/1007.1751v2
Arxiv.org
by A. B. Larionov; T. Gaitanos; U. Mosel
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We study the strangeness production in antiproton-nucleus collisions at the beam momenta from 200 MeV/c to 15 GeV/c within the Giessen Botzmann-Uehling-Uhlenbeck (GiBUU) transport model. The GiBUU model contains a very detailed description of the underlying antinucleon-nucleon cross sections, in-particular, of the strangeness production channels. We compare our calculations with the bubble chamber data on \Lambda- and K^0_S-production in antiproton-nucleus collisions and with the earlier...
Source: http://arxiv.org/abs/1107.2326v2
Arxiv.org
by A. B. Matsko; A. A. Savchenkov; L. Maleki
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We theoretically study the frequency stability of an opto-mechanical radio frequency oscillator based on resonant interaction of two optical and one mechanical modes of the same optical microcavity. A generalized expression for the phase noise of the oscillator is derived using Langevin formalism and compared to the phase noise of existing electronic oscillators.
Source: http://arxiv.org/abs/1203.2588v1
Arxiv.org
by A. Baena; A. L. Saraiva; Belita Koiller; M. J. Calderón
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We analyze the valley composition of one electron bound to a shallow donor close to a Si/barrier interface as a function of an applied electric field. A full six-valley effective mass model Hamiltonian is adopted. For low fields, the electron ground state is essentially confined at the donor. At high fields the ground state is such that the electron is drawn to the interface, leaving the donor practically ionized. Valley splitting at the interface occurs due to the valley-orbit coupling, V_vo^I...
Source: http://arxiv.org/abs/1203.6245v2
Arxiv.org
by A. Bazavov; Tanmoy Bhattacharya; C. E. DeTar; H. -T. Ding; Steven Gottlieb; Rajan Gupta; P. Hegde; Urs Heller; F. Karsch; E. Laermann; L. Levkova; Swagato Mukherjee; P. Petreczky; Christian Schmidt; R. A. Soltz; W. Soeldner; R. Sugar; Pavlos M. Vranas
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We calculate the quadratic fluctuations of net baryon number, electric charge and strangeness as well as correlations among these conserved charges in (2+1)-flavor lattice QCD at zero chemical potential. Results are obtained using calculations with tree level improved gauge and the highly improved staggered quark (HISQ) actions with almost physical light and strange quark masses at three different values of the lattice cut-off. Our choice of parameters corresponds to a value of 160 MeV for the...
Source: http://arxiv.org/abs/1203.0784v2
Arxiv.org
by A. Bialas; A. Bzdak; K. Zalewski
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Interpretation of long-range rapidity correlations in terms of the fluctuating rapidity density distribution of the system created in high-energy collisions is proposed. When applied to recent data of the STAR coll., it shows a substantial asymmetric component in the shape of this system in central Au-Au collisions, implying that boost invariance is violated on the event-by-event basis even at central rapidity. This effect may seriously influence the hydrodynamic expansion of the system.
Source: http://arxiv.org/abs/1107.1215v2
Arxiv.org
by A. Bouchez; L. Margules; R. A. Motiyenko; J-C. Guillemin; A. Walters; S. Bottinelli; C. Ceccarelli; C. Kahane
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Glycolaldehyde, a sugar-related interstellar prebiotic molecule, has recently been detected in two star-forming regions, Sgr B2(N) and G31.41+0.31. The detection of this new species increased the list of complex organic molecules detected in the interstellar medium (ISM) and adds another level to the chemical complexity present in space. Besides, this kind of organic molecule is important because it is directly linked to the origin of life. For many years, astronomers have been struggling to...
Source: http://arxiv.org/abs/1203.0899v1
Arxiv.org
by A. Braggio; D. Ferraro; M. Carrega; N. Magnoli; M. Sassetti
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We propose a general mechanism for renormalization of the tunneling exponents in edge states of the fractional quantum Hall effect. Mutual effects of the coupling with out-of-equilibrium 1/f noise and dissipation are considered both for the Laughlin sequence and for composite co- and counter-propagating edge states with Abelian or non-Abelian statistics. For states with counter-propagating modes we demonstrate the robustness of the proposed mechanism in the so called disorder-dominated phase....
Source: http://arxiv.org/abs/1203.1906v1
Arxiv.org
by A. Bravo; M. L. García-Escamilla; O. E. Villamayor U.
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The purpose of this paper is to show how Rees algebras can be applied in the study of singularities embedded in smooth schemes over perfect fields. In particular, we will study situations in which the multiplicity of a hypersurface is a multiple of the characteristic. As another application, here we indicate how the use of these algebras has trivialized local-global questions in resolution of singularities over fields of characteristic zero.
Source: http://arxiv.org/abs/1107.1797v2
Arxiv.org
by A. C. Betz; F. Vialla; D. Brunel; C. Voisin; M. Picher; A. Cavanna; A. Madouri; G. Fève; J. -M. Berroir; B. Plaçais; E. Pallecchi
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We have investigated the energy loss of hot electrons in metallic graphene by means of GHz noise thermometry at liquid helium temperature. We observe the electronic temperature T / V at low bias in agreement with the heat diffusion to the leads described by the Wiedemann-Franz law. We report on $T\propto\sqrt{V}$ behavior at high bias, which corresponds to a T4 dependence of the cooling power. This is the signature of a 2D acoustic phonon cooling mechanism. From a heat equation analysis of the...
Source: http://arxiv.org/abs/1203.2753v2
Arxiv.org
by A. Cardillo; S. Meloni; J. Gómez-Gardeñes; Y. Moreno
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In this Brief Report we study the evolutionary dynamics of the Public Goods Game in a population of mobile agents embedded in a 2-dimensional space. In this framework, the backbone of interactions between agents changes in time, allowing us to study the impact that mobility has on the emergence of cooperation in structured populations. We compare our results with a static case in which agents interact on top of a Random Geometric Graph. Our results point out that a low degree of mobility...
Source: http://arxiv.org/abs/1203.1768v2
Arxiv.org
by A. Chamballu; J. G. Bartlett; J. -B. Melin
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Surveys based on the Sunyaev-Zel'dovich (SZ) effect provide a fresh view of the galaxy cluster population, one that is complementary to X-ray surveys. To better understand the relation between these two kinds of survey, we construct an empirical cluster model using scaling relations constrained by current X-ray and SZ data. We apply our model to predict the X-ray properties of the Planck SZ Cluster Catalog (PCC) and compare them to existing X-ray cluster catalogs. We find that Planck should...
Source: http://arxiv.org/abs/1007.3193v2
Arxiv.org
by A. Crivellin; J. Rosiek; P. H. Chankowski; A. Dedes; S. Jager; P. Tanedo
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We present SUSY_FLAVOR version 2 - a Fortran 77 program that calculates low-energy flavour observables in the general R-parity conserving MSSM. For a set of MSSM parameters as input, the code gives predictions for: 1. Electric dipole moments of the leptons and the neutron. 2. Anomalous magnetic moments (i.e. g-2) of the leptons. 3. Radiative lepton decays (\mu -> e\gamma, \tau -> \mu\gamma, e\gamma). 4. Rare Kaon decays (K^0_L -> \pi^0 \nu\nu, K^+ -> \pi^+ \nu\nu). 5. Leptonic B...
Source: http://arxiv.org/abs/1203.5023v2
Arxiv.org
by A. De Pasquale; P. Facchi; V. Giovannetti; K. Yuasa
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We study the efficiency of quantum tomographic reconstruction where the system under investigation (quantum target) is indirectly monitored by looking at the state of a quantum probe that has been scattered off the target. In particular we focus on the state tomography of a qubit through a one-dimensional scattering of a probe qubit, with a Heisenberg-type interaction. Via direct evaluation of the associated quantum Cram\'{e}r-Rao bounds, we compare the accuracy efficiency that one can get by...
Source: http://arxiv.org/abs/1107.5545v2
Arxiv.org
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According to the now strongly supported concordance $\Lambda$CDM model, galaxies may be grossly described as a luminous component embedded in a dark matter halo. The density profile of these mass dominating haloes may be determined by N - body simulations which mimic the evolution of the tiny initial density perturbations during the process leading to the structures we observe today. Unfortunately, when the effect of baryons is taken into account, the situation gets much more complicated due to...
Source: http://arxiv.org/abs/1203.3377v1
Arxiv.org
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Unstable four-boson states having an approximate dimer-atom-atom structure are studied using momentum-space integral equations for the four-particle transition operators. For a given Efimov trimer the universal properties of the lowest associated tetramer are determined. The impact of this tetramer on the atom-trimer and dimer-dimer collisions is analyzed. The reliability of the three-body dimer-atom-atom model is studied.
Source: http://arxiv.org/abs/1203.6291v1
Arxiv.org
by A. Derzsi; Z. Neda
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Diversity patterns of tree species in a tropical forest community are approached by a simple lattice model and investigated by Monte Carlo simulations using a backtracking method. Our spatially explicit neutral model is based on a simple statistical physics process, namely the diffusion of seeds. The model has three parameters: the speciation rate, the size of the meta-community in which the studied tree-community is embedded, and the average surviving time of the seeds. By extensive computer...
Source: http://arxiv.org/abs/1203.0844v1
Arxiv.org
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We consider the differential cross section of electron-positron pair production by a high-energy photon in a strong Coulomb field close to the end of the electron or positron spectrum. When the momentum transfer largely exceeds the electron mass, the cross section is obtained analytically in a compact form. Coulomb corrections essentially modify the cross section even for moderate values of the nuclear charge number $Z$. In the same kinematical region, the angular distribution for bound-free...
Source: http://arxiv.org/abs/1203.2137v1
Arxiv.org
by A. E. Böhmer; P. Burger; F. Hardy; T. Wolf; P. Schweiss; R. Fromknecht; H. v. Löhneysen; C. Meingast; H. K. Mak; R. Lortz; S. Kasahara; T. Terashima; T. Shibauchi; Y. Matsuda
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High-resolution thermal-expansion and specific-heat measurements were performed on single crystalline BaFe2(As1-xPx)2 (0 < x < 0.33, x = 1). The observation of clear anomalies allows to establish the thermodynamic phase diagram which features a small coexistence region of SDW and superconductivity with a steep rise of Tc on the underdoped side. Samples that undergo the tetragonal-orthorhombic structural transition are detwinned in situ, and the response of the sample length to the...
Source: http://arxiv.org/abs/1203.2119v1
Arxiv.org
by A. E. Derbyshev; S. S. Poghosyan; A. M. Povolotsky; V. B. Priezzhev
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We consider the totally asymmetric exclusion process in discrete time with generalized updating rules. We introduce a control parameter into the interaction between particles. Two particular values of the parameter correspond to known parallel and sequential updates. In the whole range of its values the interaction varies from repulsive to attractive. In the latter case the particle flow demonstrates an apparent jamming tendency not typical for the known updates. We solve the master equation...
Source: http://arxiv.org/abs/1203.0902v1
Arxiv.org
by A. E. Koudou; P. Vallois
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We define Letac-Wesolowski-Matsumoto-Yor (LWMY) functions as decreasing functions from $(0,\infty)$ onto $(0,\infty)$ with the following property: there exist independent, positive random variables $X$ and $Y$ such that the variables $f(X+Y)$ and $f(X)-f(X+Y)$ are independent. We prove that, under additional assumptions, there are essentially four such functions. The first one is $f(x)=1/x$. In this case, referred to in the literature as the Matsumoto-Yor property, the law of $X$ is generalized...
Source: http://arxiv.org/abs/1203.0381v1
Arxiv.org
by A. Eghbali; A. Rezaei-Aghdam
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We generalize the formulation of Poisson-Lie T-dual sigma models on manifolds to supermanifolds. In this respect, we formulate 1+1 dimensional string cosmological models on the Lie supergroup C^3 and its dual (A_1,1 + 2A)^0_(1,0,0), which are coupled to two fermionic fields. Then, we solve the equations of motion of the models and show that there is a essential singularity for the metric of the original model and its dual.
Source: http://arxiv.org/abs/1107.2041v3
Arxiv.org
by A. Feoli; L. Mancini; V. Rillo; M. Grasso
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Observations of distant type Ia supernovae (SNe Ia), used as standard candles, support the notion that the Cosmos is filled with a mysterious form of energy, the dark energy. The constraints on cosmological parameters derived from data of SNe Ia and the measurements of the cosmic microwave background anisotropies indicate that the dark energy amounts to roughly 70% of all the energy contained in the Universe. In the hypothesis of a flat Universe, we investigate if the dark energy is really...
Source: http://arxiv.org/abs/1203.6269v1
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by A. Fernandez-Panella; V. Balédent; D. Braithwaite; Luigi Paolasini; Roberto Verbeni; G. Lapertot; Jean-Pascal Rueff
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We report Resonant inelastic x-ray scattering measurements (RIXS) in YbCu$_2$Si$_2$ at the Yb L$_{3}$ edge under high pressure (up to 22 GPa) and at low temperatures (down to 7 K) with emphasis on the vicinity of the transition to a magnetic ordered state. We find a continuous valence change towards the trivalent state with increasing pressure but with a pronounced change of slope close to the critical pressure. Even at 22 GPa the Yb$^{+3}$ state is not fully achieved. The pressure where this...
Source: http://arxiv.org/abs/1203.3567v1
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by A. Frisch; K. Aikawa; M. Mark; A. Rietzler; J. Schindler; E. Zupanic; R. Grimm; F. Ferlaino
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We report on the experimental realization of a robust and efficient magneto-optical trap for erbium atoms, based on a narrow cooling transition at 583nm. We observe up to $N=2 \times 10^{8}$ atoms at a temperature of about $T=15 \mu K$. This simple scheme provides better starting conditions for direct loading of dipole traps as compared to approaches based on the strong cooling transition alone, or on a combination of a strong and a narrow kHz transition. Our results on Er point to a general,...
Source: http://arxiv.org/abs/1203.1460v2
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by A. Fuhrmanek; R. Bourgain; Y. R. P. Sortais; A. Browaeys
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We study light-assisted collisions in an ensemble containing a small number (~3) of cold Rb87 atoms trapped in a microscopic dipole trap. Using our ability to operate with one atom exactly in the trap, we measure the one-body heating rate associated to a near-resonant laser excitation, and we use this measurement to extract the two-body loss rate associated to light-assisted collisions when a few atoms are present in the trap. Our measurements indicate that the two-body loss rate can reach...
Source: http://arxiv.org/abs/1107.5781v3
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by A. Fête; S. Gariglio; A. D. Caviglia; J. -M. Triscone; M. Gabay
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We report measurements of the normal state in-plane magnetoconductance in gated LaAlO$_3$-SrTiO$_3$ samples. As the orientation of the magnetic field changes within the plane of the interface, the signal displays periodic oscillations with respect to the angle between the field and the direction of the current. We show that in the underdoped to optimally doped range, a Fermi surface reconstruction takes place due to the Rashba spin-orbit term and that the oscillations are due to a magnetic...
Source: http://arxiv.org/abs/1203.5239v2
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by A. G. Afonin; V. T. Baranov; M. K. Bulgakov; Yu. A. Chesnokov; P. N. Chirkov; E. V. Lobanova; I. S. Lobanov; A. N. Lunkov; V. A. Maisheev; I. V. Poluektov; Yu. E. Sandomirskiy; I. A. Yazynin
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Recently it was proposed to apply a bent single crystal with decreasing curvature instead of uniform bending for improvement of extraction and collimation of a circulating beam in particle accelerators. In the given paper created crystal devices with a variable curvature, realizing this idea are described. Results of measurement of curvature along a crystal plate are informed. It is shown, that with the help of the developed devices it is possible to carry out also high energy beam focusing....
Source: http://arxiv.org/abs/1203.5586v1
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Searches for light charged Higgs bosons (H^\pm) in the decay of top quarks, t -> H^\pm b, are being carried out at the LHC and at the Tevatron. It is assumed that the dominant decay channels for such an H^\pm state are either H^\pm -> \tau\nu or H^\pm -> cs, and separate searches are performed with comparable sensitivity to the parameters m_{H^\pm} and tanbeta of the scalar potential. The branching ratio for the decay H^\pm -> cb can be as large as 80% in the Aligned Two Higgs...
Source: http://arxiv.org/abs/1203.5769v2
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by A. Gallenne; P. Kervella; A. Mérand; H. McAlister; T. ten Brummelaar; V. Coudé du Foresto; J. Sturmann; L. Sturmann; N. Turner; C. Farrington; P. J. Goldfinger
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We report the first angular diameter measurements of two classical Cepheids, FF Aql and T Vul, that we have obtained with the FLUOR instrument installed at the CHARA interferometric array. We obtain average limb-darkened angular diameters of \theta_LD = 0.878 +/- 0.013 mas and \theta_LD = 0.629 +/- 0.013 mas, respectively for FF Aql and T Vul. Combining these angular diameters with the HST-FGS trigonometric parallaxes leads to linear radii R = 33.6 +/- 2.2 Rsol and R = 35.6 +/- 4.4 Rsol,...
Source: http://arxiv.org/abs/1203.6682v1
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by A. Garcia-Rissmann; A. Rodriguez-Ardila; T. A. A. Sigut; A. K. Pradhan
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In AGN spectra, a series of FeII multiplets form a pseudo-continuum that extends from the ultraviolet to the near-infrared (NIR). This emission is believed to originate in the Broad Line Region (BLR), and it has been known for a long time that pure photoionization fails to reproduce it in the most extreme cases, as does the collisional-excitation alone. The most recent models by Sigut & Pradhan (2003) include details of the FeII ion microphysics and cover a wide range in ionization...
Source: http://arxiv.org/abs/1203.2949v1
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by A. Goban; K. S. Choi; D. J. Alton; D. Ding; C. Lacroûte; M. Pototschnig; T. Thiele; N. P. Stern; H. J. Kimble
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We report the experimental realization of an optical trap that localizes single Cs atoms ~215 nm from surface of a dielectric nanofiber. By operating at magic wavelengths for pairs of counter-propagating red- and blue-detuned trapping beams, differential scalar light shifts are eliminated, and vector shifts are suppressed by ~250. We thereby measure an absorption linewidth \Gamma/2\pi = 5.7 \pm 0.1 MHz for the Cs 6S1/2,F=4 - 6P3/2,F'=5 transition, where \Gamma/2\pi = 5.2 MHz in free space....
Source: http://arxiv.org/abs/1203.5108v1
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by A. Gruppuso; P. Natoli; N. Mandolesi; A. De Rosa; F. Finelli; F. Paci
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We constrain the rotation angle $\alpha$ of the linear polarization of CMB photons using the large angular scale (up to $\sim 4^\circ$) signal in WMAP 7 year data. At these scales, the CMB polarization pattern probes mostly the reionization era. A genuine rotation may be interpreted as cosmological birefringence, which is a well known tracer of new physics, through the breakdown of fundamental symmetries. Our analysis provides $\alpha = -1.6^{\circ} \pm 1.7^{\circ} (3.4^{\circ})$ at 68% (95%)...
Source: http://arxiv.org/abs/1107.5548v2
The objective of this paper is to provide a convergent numerical approximation of the Pareto optimal set for finite-horizon multiobjective optimal control problems for which the objective space is not necessarily convex. Our approach is based on Viability Theory. We first introduce the set-valued return function V and show that the epigraph of V is equal to the viability kernel of a properly chosen closed set for a properly chosen dynamics. We then introduce an approximate set-valued return...
Source: http://arxiv.org/abs/1203.0292v1
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by A. Gusdorf; S. Anderl; R. Guesten; J. Stutzki; H-W. Huebers; P. Hartogh; S. Heyminck; Y. Okada
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Context. Observing supernova remnants (SNRs) and modelling the shocks they are associated with is the best way to quantify the energy SNRs re-distribute back into the Interstellar Medium (ISM). Aims. We present comparisons of shock models with CO observations in the F knot of the W28 supernova remnant. These comparisons constitute a valuable tool to constrain both the shock characteristics and pre-shock conditions. Methods. New CO observations from the shocked regions with the APEX and SOFIA...
Source: http://arxiv.org/abs/1203.2519v1
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by A. Hartanto; F. P. Zen; J. S. Kosasih; L. T. Handoko
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The symmetry breaking of five-dimensional SU(6) GUT is realized by Scherk-Schwarz mechanisms through trivial and pseudo nontrivial orbifold S1/Z2 breakings to produce dimensional deconstruction 5D SU(6) \rightarrow4D SU(6). The latter also induces near-brane weakly-coupled SU(6) Baby Higgs to further break the symmetry into SU(3)C \otimes SU(3)H \otimes U(1)C. The model successfully provides a scenario of the origin of (Little) Higgs from GUT scale, produces the (intermediate and light) Higgs...
Source: http://arxiv.org/abs/1203.6165v1
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by A. Hill; A. Sinner; K. Ziegler
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We calculate the optical Hall conductivity within the Kubo formalism for systems with gapped spectral nodes, where the latter have a power-law dispersion with exponent n. The optical conductivity is proportional to n and there is a characteristic logarithmic singularity as the frequency approaches the gap energy. The optical Hall conductivity is almost unaffected by thermal fluctuations and disorder for n=1, whereas disorder has a stronger effect on transport properties if n=2.
Source: http://arxiv.org/abs/1005.3211v3
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by A. Holkundkar; G. Brodin; M. Marklund
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The acceleration of charged particles, producing collimated mono-energetic beams, over short distances holds the promise to offer new tools in medicine and diagnostics. Here, we consider a possible mechanism for accelerating protons to high energies by using a phase-modulated circularly polarized electromagnetic wave propagating along a constant magnetic field. It is observed that a plane wave with dimensionless amplitude of 0.1 is capable to accelerate a 1 KeV proton to 386 MeV under optimum...
Source: http://arxiv.org/abs/1203.0110v1
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We calculate the "naive non-abelianization" (NNA) contributions of the higher-twist Feynman diagrams to the large-$p_T$ inclusive pion production cross section in proton-proton collisions in the case of the running coupling and frozen coupling approaches. We compare the resummed "naive non-abelianization" higher-twist cross sections with the ones obtained in the framework of the frozen coupling approach and leading-twist cross section. The structure of infrared renormalon...
Source: http://arxiv.org/abs/1107.1562v2
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A novel model of complex quantum harmonic oscillator is found to account for the observed Fractional quantum Hall effect (FQHE). The sequences of the observed FQHE conductivity and charge are explained. The two sequences are found to express a quantity and its complex conjugated partner. The oscillator is found to have two degenerates states, $\psi_n$, with angular momenta $\pm \,n\,\hbar$\,, where $h = 2\pi \hbar $ is the Planck's constant, and $n$ is the principal quantum number of the...
Source: http://arxiv.org/abs/1203.0613v2
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by A. I. Chugunov; M. E. Gusakov
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For the first time nonradial oscillations of superfluid nonrotating stars are self-consistently studied at finite stellar temperatures. We apply a realistic equation of state and realistic density dependent model of critical temperature of neutron and proton superfluidity. In particular, we discuss three-layer configurations of a star with no neutron superfluidity at the centre and in the outer region of the core but with superfluid intermediate region. We show, that oscillation spectra contain...
Source: http://arxiv.org/abs/1107.4242v2
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by A. I. Gómez-Ruiz; A. Gusdorf; S. Leurini; C. Codella; R. Güsten; F. Wyrowski; M. A. Requena-Torres; C. Risacher; S. F. Wampfler
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We present and analyze two spectrally resolved high-J CO lines towards the molecular outflow Cep E, driven by an intermediate-mass class 0 protostar. Using the GREAT receiver on board SOFIA, we observed the CO (12--11) and (13--12) transitions (E_u ~ 430 and 500 K, respectively) towards one position in the blue lobe of this outflow, that had been known to display high-velocity molecular emission. We detect the outflow emission in both transitions, up to extremely high velocities (~ 100 km/s...
Source: http://arxiv.org/abs/1203.1890v1
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by A. I. Smolyakov; W. Frias; I. D. Kaganovich; Y. Raitses
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New class instabilities is identified in Hall plasmas in configurations with open magnetic field lines. It is shown that sheath resistivity results in a robust instability driven by the equilibrium electric field. It is conjectured that these instabilities play a crucial role in anomalous transport in Hall plasmas devices.
Source: http://arxiv.org/abs/1203.6872v1
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by A. Ibort; G. Marmo
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The group of automorphisms of the geometry of an integrable system is considered. The geometrical structure used to obtain it is provided by a normal form representation of integrable systems that do not depend on any additional geometrical structure like symplectic, Poisson, etc. Such geometrical structure provides a generalized toroidal bundle on the carrier space of the system. Non--canonical diffeomorphisms of such structure generate alternative Hamiltonian structures for complete...
Source: http://arxiv.org/abs/1203.1663v1
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by A. Ibort; J. M. Pérez-Pardo
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A new notion of controllability for quantum systems that takes advantage of the linear superposition of quantum states is introduced. We call such notion von Neumann controllabilty and it is shown that it is strictly weaker than the usual notion of pure state and operator controlability. We provide a simple and effective characterization of it by using tools from the theory of unitary representations of Lie groups. In this sense we are able to approach the problem of control of quantum states...
Source: http://arxiv.org/abs/1203.2380v1
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by A. Ibort; P. Linares; J. G. Llavona
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Given a multi-index sequence $\mu_{\mathbf{k}}$, $\mathbf{k} = (k_1,..., k_n) \in \mathbb{N}_0^n$, necessary and sufficient conditions are given for the existence of a regular Borel polymeasure $\gamma$ on the unit interval $I= [0,1]$ such that $\mu_{\mathbf{k}} = \int_{I^n} t_1^{k_1}\otimes ... \otimes t_n^{k_n} \gamma$. This problem will be called the weak multilinear Hausdorff problem of moments for $\mu_{\mathbf{k}}$. Comparison with classical results will allow us to relate the weak...
Source: http://arxiv.org/abs/1203.2967v1
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by A. Ibort; P. Linares; J. G. Llavona
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We present a new proof of a Sundaresan's result which shows that the space of orthogonally additive polynomials $\mathcal{P}_o(^k\ell_p)$ is isometrically isomorphic to $\ell_{p/p-k}$ if $k
Source: http://arxiv.org/abs/1203.2968v1
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by A. Ibort; P. Linares; J. G. Llavona
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The aim of this article is to prove a representation theorem for orthogonally additive polynomials in the spirit of the recent theorem on representation of orthogonally additive polynomials on Banach lattices but for the setting of Riesz spaces. To this purpose the notion of $p$--orthosymmetric multilinear form is introduced and it is shown to be equivalent to the orthogonally additive property of the corresponding polynomial. Then the space of positive orthogonally additive polynomials on an...
Source: http://arxiv.org/abs/1203.2379v1
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A toy model for glioma treatment by a radio frequency electric field is suggested. This low-intensity, intermediate-frequency alternating electric field is known as the tumor-treating-field (TTF). In the framework of this model the efficiency of this TTF is estimated, and the interplay between the TTF and the migration-proliferation dichotomy of cancer cells is considered. The model is based on a modification of a comb model for cancer cells, where the migration-proliferation dichotomy becomes...
Source: http://arxiv.org/abs/1203.2450v1
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by A. J. Bennett; M. A. Pooley; R. M. Stevenson; I. Farrer; D. A. Ritchie; A. J. Shields
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We study the free evolution of a superposition initialized with high fidelity in the neutral-exciton state of a quantum dot. Readout of the state at later times is achieved by polarized photon detection, averaged over a large number of cycles. By controlling the fine-structure splitting (FSS) of the dot with a dc electric field, we show a reduction in the degree of polarization of the signal when the splitting is minimized. In analogy with the "free induction decay" observed in...
Source: http://arxiv.org/abs/1203.5908v1
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by A. J. Bennett; M. A. Pooley; R. M. Stevenson; M. B. Ward; R. B. Patel; A. Boyer de la Giroday; N. Sköld; I. Farrer; C. A. Nicoll; D. A. Ritchie; A. J. Shields
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The signature of coherent coupling between two quantum states is an anticrossing in their energies as one is swept through the other. In single semiconductor quantum dots containing an electron-hole pair the eigenstates form a two-level system that can be used to demonstrate quantum effects in the solid state, but in all previous work these states were independent. Here we describe a technique to control the energetic splitting of these states using a vertical electric field, facilitating the...
Source: http://arxiv.org/abs/1203.5909v1
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by A. J. Cuesta; T. E. Jeltema; F. Zandanel; S. Profumo; F. Prada; G. Yepes; A. Klypin; Y. Hoffman; S. Gottloeber; J. Primack; M. A. Sanchez-Conde; C. Pfrommer
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We present all-sky simulated Fermi maps of gamma-rays from dark matter decay and annihilation in the Local Universe. The dark matter distribution is obtained from a constrained cosmological simulation of the neighboring large-scale structure provided by the CLUES project. The dark matter fields of density and density squared are then taken as an input for the Fermi observation simulation tool to predict the gamma-ray photon counts that Fermi would detect in 5 years of all-sky survey for given...
Source: http://arxiv.org/abs/1007.3469v3
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by A. J. van der Schaft; B. M. Maschke
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In this paper we present a unifying geometric and compositional framework for modeling complex physical network dynamics as port-Hamiltonian systems on open graphs. Basic idea is to associate with the incidence matrix of the graph a Dirac structure relating the flow and effort variables associated to the edges, internal vertices, as well as boundary vertices of the graph, and to formulate energy-storing or energy-dissipating relations between the flow and effort variables of the edges and...
Source: http://arxiv.org/abs/1107.2006v2
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by A. K. Likhoded; A. V. Luchinsky; S. V. Poslavsky
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In the present paper, we discuss the $P$-wave bottomonium production within the both color octet and color singlet models in NLO at LHC energies. We calculate the production and the transverse momentum distributions of the $\chi_{1,2b}$ states. We found, that the ratios of bottomonium and charmonium spin states are fundamentally complementary at different $p_T$ scales. We give predictions for the ratio of the $n=2$ and $n=1$ radial excitations production cross sections.
Source: http://arxiv.org/abs/1203.4893v5
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Using multi-wavelength observations of Solar and Heliospheric Observatory (SoHO)/Michelson Doppler Imager (MDI), Transition Region and Coronal Explorer (TRACE) 171 \AA, and H$\alpha$ from Culgoora Solar Observatory at Narrabri, Australia, we present a unique observational signature of a propagating supersonic plasma blob before an M6.2 class solar flare in AR10808 on 9th September 2005. The blob was observed between 05:27 UT to 05:32 UT with almost a constant shape for the first 2-3 minutes,...
Source: http://arxiv.org/abs/1203.6209v1
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by A. Kowalewska-Kudłaszyk; J. K. Kalaga; W. Leoński; V. Cao Long
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We discuss a system of a nonlinear Kerr-like oscillator externally pumped by ultra-short, external, coherent pulses. For such a system, we analyse the application of the Kullback-Leibler quantum divergence $K[\rho||\sigma]$ to the detection of quantum chaotic behaviour. Defining linear and nonlinear quantum divergences, and calculating their power spectra, we show that these parameters are more suitable indicators of quantum chaos than the fidelity commonly discussed in the literature, and are...
Source: http://arxiv.org/abs/1203.6774v1
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by A. Kusina; T. Stavreva; S. Berge; F. I. Olness; I. Schienbein; K. Kovarik; T. Jezo; J. Y. Yu; K. Park
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Global analyses of Parton Distribution Functions (PDFs) have provided incisive constraints on the up and down quark components of the proton, but constraining the other flavor degrees of freedom is more challenging. Higher-order theory predictions and new data sets have contributed to recent improvements. Despite these efforts, the strange quark PDF has a sizable uncertainty, particularly in the small x region. We examine the constraints from experiment and theory, and investigate the impact of...
Source: http://arxiv.org/abs/1203.1290v2
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by A. L. Agore
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The main properties of the crossed product in the category of Hopf algebras are investigated. Let $A$ and $H$ be two Hopf algebras connected by two morphism of coalgebras $\triangleright : H\ot A \to A$, $f:H\ot H\to A$. The crossed product $A #_{f}^{\triangleright} H$ is a new Hopf algebra containing $A$ as a normal Hopf subalgebra. Furthermore, a Hopf algebra $E$ is isomorphic as a Hopf algebra to a crossed product of Hopf algebras $A #_{f}^{\triangleright} H$ if and only if $E$ factorizes...
Source: http://arxiv.org/abs/1203.2454v2
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Let $A \subseteq E$ be an extension of Hopf algebras such that there exists a normal left $A$-module coalgebra map $\pi : E \to A$ that splits the inclusion. We shall describe the set of all coquasitriangular structures on the Hopf algebra $E$ in terms of the datum $(A, E, \pi)$ as follows: first, any such extension $E$ is isomorphic to a unified product $A \ltimes H$, for some unitary subcoalgebra $H$ of $E$ (\cite{am2}). Then, as a main theorem, we establish a bijective correspondence between...
Source: http://arxiv.org/abs/1203.2455v1
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A concise survey of the advanced unifying ideas of modern physics, namely, spontaneous symmetry breaking, quasiaverages, quantum protectorate and emergence was presented. The interrelation of the concepts of symmetry breaking, quasiaverages and quantum protectorate was analyzed in the context of quantum theory and statistical physics. The main aim of this analysis was to demonstrate the connection and interrelation of these conceptual advances of the many-body physics and to try to show...
Source: http://arxiv.org/abs/1203.3139v1
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by A. Lajevardipour; M. Neek-Amal; F. M. Peeters
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Using the valence force field model of Perebeinos and Tersoff [Phys. Rev. B {\bf79}, 241409(R) (2009)], different energy modes of suspended graphene subjected to tensile or compressive strain are studied. By carrying out Monte Carlo simulations it is found that: i) only for small strains ($|\varepsilon| \lessapprox 0.02$) the total energy is symmetrical in the strain, while it behaves completely different beyond this threshold; ii) the important energy contributions in stretching experiments...
Source: http://arxiv.org/abs/1203.0610v1
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by A. Lenz; U. Nierste; J. Charles; S. Descotes-Genon; H. Lacker; S. Monteil; V. Niess; S. T'Jampens
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We perform model-independent statistical analyses of three scenarios accommodating New Physics (NP) in Delta F=2 flavour-changing neutral current amplitudes. In a scenario in which NP in B_d-B_d-bar and B_s-B_s-bar is uncorrelated, we find the parameter point representing the Standard-Model disfavoured by 2.4 standard deviations. However, recent LHCb data on B_s neutral-meson mixing forbid a good accommodation of the D0 data on the semileptonic CP asymmetry A_SL. We introduce a fourth scenario...
Source: http://arxiv.org/abs/1203.0238v2
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by A. Liam Fitzpatrick; Wick Haxton; Emanuel Katz; Nicholas Lubbers; Yiming Xu
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We extend and explore the general non-relativistic effective theory of dark matter (DM) direct detection. We describe the basic non-relativistic building blocks of operators and discuss their symmetry properties, writing down all Galilean-invariant operators up to quadratic order in momentum transfer arising from exchange of particles of spin 1 or less. Any DM particle theory can be translated into the coefficients of an effective operator and any effective operator can be simply related to...
Source: http://arxiv.org/abs/1203.3542v3
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by A. Liermann; W. -R. Hamann; L. M. Oskinova
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The Quintuplet, one of three massive stellar clusters in the Galactic center, is located about 30pc in projection from Sagittarius A*. Based on near-infrared K-band spectra we determine temperatures and luminosities for all stars in our sample and construct the Herztsprung-Russell diagram. We find two distinct groups: early-type OB stars and late-type KM stars, well separated from each other. By comparison with Geneva stellar evolution models we derive initial masses exceeding 8 solar masses...
Source: http://arxiv.org/abs/1203.2435v1
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by A. Luo; T. Wolf; Y. Wang; M. Malnou; C. Ulysse; G. Faini; P. Febvre; J. Lesueur; N. Bergeal
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In this letter, we present the study of the high-frequency mixing properties of ion irradiated YBa2Cu3O7 Josephson nano-junctions. The frequency range, spanning above and below the characteristic frequencies fc of the junctions, permits clear observation of the transition between two mixing regimes. The experimental conversion gain was found to be in good agreement with the prediction of the three ports model. Finally, we discuss the potential of the junctions to build a Josephson mixer...
Source: http://arxiv.org/abs/1203.1734v2
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We show that there are two reasons why the partial width for the transition $\Gamma_1(\Upsilon(3S)\rightarrow \gamma\chi_{b1}(1P))$ is suppressed. Firstly, the spin-averaged matrix element (m.e.) $\bar{I(3S|r|1P_J)}$ is small, being equal to 0.023 GeV$^{-1}$ in our relativistic calculations. Secondly, the spin-orbit splittings produce relatively large contributions, giving $I(3S|r|1P_2)=0.066$ GeV$^{-1}$, while due to large cancellation the m.e. $I(3S|r|1P_1)=-0.020$ GeV$^{-1}$ is small and...
Source: http://arxiv.org/abs/1203.0936v2
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by A. M. Covington; A. Aguilar; I. R. Covington; G. Hinojosa; C. A. Shirley; I. Álvarez; C. Cisneros; I. Dominguez-Lopez; M. M. Sant'Anna; A. S. Schlachter; C. P. Ballance; B. M. McLaughlin
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Absolute cross-section measurements for valence-shell photoionization of Ar$^{+}$ ions are reported for photon energies ranging from 27.4 eV to 60.0 eV. The data, taken by merging beams of ions and synchrotron radiation at a photon energy resolution of 10 meV, indicate that the primary ion beam was a statistically weighted mixture of the $^2P^o_{3/2}$ ground state and the $^2P^o_{1/2}$ metastable state of Ar$^{+}$. Photoionization of this C$\ell$-like ion is characterized by multiple Rydberg...
Source: http://arxiv.org/abs/1203.4292v1
Arxiv.org
by A. M. Hughes; D. J. Wilner; B. Mason; J. M. Carpenter; R. Plambeck; H. -F. Chiang; S. M. Andrews; J. P. Williams; A. Hales; K. Su; E. Chiang; S. Dicker; P. Korngut; M. Devlin
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Clumpy structure in the debris disk around Vega has been previously reported at millimeter wavelengths and attributed to concentrations of dust grains trapped in resonances with an unseen planet. However, recent imaging at similar wavelengths with higher sensitivity has disputed the observed structure. We present three new millimeter-wavelength observations that help to resolve the puzzling and contradictory observations. We have observed the Vega system with the Submillimeter Array (SMA) at a...
Source: http://arxiv.org/abs/1203.0318v1
Arxiv.org
by A. M. Marino; J. B. Clark; Q. Glorieux; P. D. Lett
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We show that it is possible to use the spatial quantum correlations present in twin beams to extract information about the shape of a mask in the path of one of the beams. The scheme, based on noise measurements through homodyne detection, is useful in the regime where the number of photons is low enough that direct detection with a photodiode is difficult but high enough that photon counting is not an option. We find that under some conditions the use of quantum states of light leads to an...
Source: http://arxiv.org/abs/1203.0577v1
Arxiv.org
by A. M. S. Smith; D. R. Anderson; N. Madhusudhan; J. Southworth; A. Collier Cameron; J. Blecic; J. Harrington; C. Hellier; P. F. L. Maxted; D. Pollacco; D. Queloz; B. Smalley; A. H. M . J. Triaud; P. J. Wheatley
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Aims. We observe occultations of WASP-24b to measure brightness temperatures and to determine whether or not its atmosphere exhibits a thermal inversion (stratosphere). Methods. We observed occultations of WASP-24b at 3.6 and 4.5 {\mu}m using the Spitzer Space Telescope. It has been suggested that there is a correlation between stellar activity and the presence of inversions, so we analysed existing HARPS spectra in order to calculate log R'HK for WASP-24 and thus determine whether or not the...
Source: http://arxiv.org/abs/1203.6017v2
Arxiv.org
by A. M. Yazdani; S. Jalalzadeh; K. Atazadeh
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We study the induced 4-dimensional linearized Einstein field equations in an m-dimensional bulk space by means of a confining potential. It is shown that in this approach the mass of graviton is quantized. The cosmological constant problem is also addressed within the context of this approach. We show that the difference between the values of the cosmological constant in particle physics and cosmology stems from our measurements in two different scales, small and large.
Source: http://arxiv.org/abs/1203.3762v2
Arxiv.org
by A. Malakis; A. Nihat Berker; N. G. Fytas; T. Papakonstantinou
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The effects of bond randomness on the universality aspects of the simple cubic lattice ferromagnetic Blume-Capel model are discussed. The system is studied numerically in both its first- and second-order phase transition regimes by a comprehensive finite-size scaling analysis. We find that our data for the second-order phase transition, emerging under random bonds from the second-order regime of the pure model, are compatible with the universality class of the 3d random Ising model....
Source: http://arxiv.org/abs/1203.0985v2
Arxiv.org
by A. Malakis; G. Gulpinar; Y. Karaaslan; T. Papakonstantinou; G. Aslan
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The Ising model S=1/2 and the S=1 model are studied by efficient Monte Carlo schemes on the (3,4,6,4) and the (3,3,3,3,6) Archimedean lattices. The algorithms used, a hybrid Metropolis-Wolff algorithm and a parallel tempering protocol, are briefly described and compared with the simple Metropolis algorithm. Accurate Monte Carlo data are produced at the exact critical temperatures of the Ising model for these lattices. Their finite-size analysis provide, with high accuracy, all critical...
Source: http://arxiv.org/abs/1203.4507v1
Arxiv.org
by A. Maleknejad; M. M. Sheikh-Jabbari
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In this work we revisit Wald's cosmic no-hair theorem in the context of accelerating Bianchi cosmologies for a generic cosmic fluid with non-vanishing anisotropic stress tensor and when the fluid energy momentum tensor is of the form of a cosmological constant term plus a piece which does not respect strong or dominant energy conditions. Such a fluid is the one appearing in inflationary models. We show that for such a system anisotropy may grow, in contrast to the cosmic no-hair conjecture. In...
Source: http://arxiv.org/abs/1203.0219v2