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Arxiv.org
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We review the subject of CP violation in the $B$ meson system within the Standard Model of CP violation, which is based on a complex phase in the Cabibbo-Kobayashi-Maskawa (CKM) matrix. Three kinds of CP nonconservation are studied: In $B^0-\Bbar$ mixing, in mixed neutral $B$ decays to states which are common decay products of $B^0$ and $\Bbar$ and in direct decays of charged $B$ mesons. Measurements of certain CP asymmetries are shown to determine the three angles of the CKM unitarity...
Source: http://arxiv.org/abs/hep-ph/9411385v1
A proof of Goldstone's theorem is given for the case in which global chiral symmetry is dynamically broken. The proof highlights a needed consistency between the exact Schwinger--Dyson equation for the fermion propagator and the exact Bethe--Salpeter equation for fermion--antifermion bound states. A criterion, based on the Cornwall, Jackiw and Tomboulis effective action for composite operators, is provided for maintaining the consistency when the equations are modified by approximations. For...
Source: http://arxiv.org/abs/hep-th/9411239v1
Arxiv.org
by K. Funakubo; A. Kakuto; S. Otsuki; K. Takenaga; F. Toyoda
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By treating CP-violating interaction as a perturbative term, we solved in a previous paper the Dirac equation in the background of electroweak bubble wall, and obtained the transmission and reflection coefficients for a chiral fermion incident from the symmetric-phase region. We give the transmission and reflection coefficients under the other boundary condition, that is, the case of the fermion incident from the broken-phase region. There hold the respective sets of unitarity relations and...
Source: http://arxiv.org/abs/hep-ph/9407207v1
Arxiv.org
by Simon C. Davenport; Steven H. Simon
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In this paper we study fractional quantum Hall composite fermion wavefunctions at filling fractions \nu = 2/3, 3/5, and 4/7. At each of these filling fractions, there are several possible wavefunctions with different spin polarizations, depending on how many spin-up or spin-down composite fermion Landau levels are occupied. We calculate the energy of the possible composite fermion wavefunctions and we predict transitions between ground states of different spin polarizations as the ratio of...
Source: http://arxiv.org/abs/1203.0004v3
Arxiv.org
by A. V. Kuznetsov; N. V. Mikheev; A. V. Serghienko
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The low-energy manifestations of a minimal extension of the electroweak standard model based on the quark-lepton symmetry $SU(4)_V \otimes SU(2)_L \otimes G_R$ of the Pati--Salam type are analyzed. Given this symmetry the third type of mixing in the interactions of the $SU(4)_V$ leptoquarks with quarks and leptons is shown to be required. An additional arbitrariness of the mixing parameters could allow, in principle, to decrease noticeably the lower bound on the vector leptoquark mass...
Source: http://arxiv.org/abs/1203.0196v2
Arxiv.org
by D0 Collaboration
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We present a measurement of the W boson mass using data corresponding to 4.3fb^-1 of integrated luminosity collected with the D0 detector during Run II at the Fermilab Tevatron p\bar{p} collider. With a sample of 1,677,394 W -> e\nu candidate events, we measure M_W = 80.367 +/- 0.026 GeV. This result is combined with an earlier D0 result determined using an independent Run II data sample, corresponding to 1fb^-1 of integrated luminosity, to yield M_W = 80.375 +/- 0.023 GeV.
Source: http://arxiv.org/abs/1203.0293v2
Arxiv.org
by Patricia Gonçalves
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We consider the one-dimensional asymmetric zero-range process starting from a step decreasing profile. In the hydrodynamic limit this initial condition leads to the rarefaction fan of the associated hydrodynamic equation. Under this initial condition and for totally asymmetric jumps, we show that the weighted sum of joint probabilities for second class particles sharing the same site is convergent and we compute its limit. For partially asymmetric jumps we derive the Law of Large Numbers for...
Source: http://arxiv.org/abs/1203.0287v1
Arxiv.org
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We update the previous analysis of correlation between ultra-high energy cosmic rays (UHECR) and active galactic nuclei (AGN), using 69 UHECR events with energy $E\ge55\,{\rm EeV}$ released in 2010 by Pierre Auger observatory and 862 AGN within the distance $d\le100\,{\rm Mpc}$ listed in the 13th edition of V\'eron-Cetty and V\'eron AGN catalog. To make the test hypothesis definite, we use the simple AGN source model in which UHECR are originated both from AGN, with the fraction $f_A$, and from...
Source: http://arxiv.org/abs/1203.0386v3
Arxiv.org
by Ardavan Oskooi; Pedro A. Favuzzi; Yoshinori Tanaka; Hiroaki Shigeta; Yoichi Kawakami; Susumu Noda
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We present a general framework for the design of thin-film photovoltaics based on a partially-disordered photonic crystal that has both enhanced absorption for light trapping and reduced sensitivity to the angle and polarization of incident radiation. The absorption characteristics of different lattice structures are investigated as an initial periodic structure is gradually perturbed. We find that an optimal amount of disorder controllably introduced into a multi-lattice photonic crystal...
Source: http://arxiv.org/abs/1203.0363v1
Arxiv.org
by Charles Delorme; Guillermo Pineda-Villavicencio
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In 1855 H. J. S. Smith proved Fermat's Two Squares using the notion of palindromic continuants. In this paper we extend Smith's approach to proper quadratic form representations in some commutative Euclidean rings, including rings of integers and rings of polynomials over fields of characteristic different from 2. While our results are natural extensions of Smith's approach and are unlikely to be new, we believe our presentation is new.
Source: http://arxiv.org/abs/1203.0347v1
Arxiv.org
by Vitaly Feldman
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Since its introduction by Valiant in 1984, PAC learning of DNF expressions remains one of the central problems in learning theory. We consider this problem in the setting where the underlying distribution is uniform, or more generally, a product distribution. Kalai, Samorodnitsky and Teng (2009) showed that in this setting a DNF expression can be efficiently approximated from its "heavy" low-degree Fourier coefficients alone. This is in contrast to previous approaches where boosting...
Source: http://arxiv.org/abs/1203.0594v3
Arxiv.org
by E. Caffau; P. Bonifacio; P. François; M. Spite; F. Spite; S. Zaggia; H. -G. Ludwig; M. Steffen; L. Mashonkina; L. Monaco; L. Sbordone; P. Molaro; R. Cayrel; B. Plez; V. Hill; F. Hammer; S. Randich
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Context: The discovery and chemical analysis of extremely metal-poor stars permit a better understanding of the star formation of the first generation of stars and of the Universe emerging from the Big Bang. aims: We report the study of a primordial star situated in the centre of the constellation Leo (SDSS J102915+172027). method: The star, selected from the low resolution-spectrum of the Sloan Digital Sky Survey, was observed at intermediate (with X-Shooter at VLT) and at high spectral...
Source: http://arxiv.org/abs/1203.2607v1
Arxiv.org
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Let G be a complete Kac-Moody group of rank n \geq 2 over the finite field of order q, with Weyl group W and building \Delta. We first show that if W is right-angled, then for all q \neq 1 mod 4 the group G admits a cocompact lattice \Gamma which acts transitively on the chambers of \Delta. We also obtain a cocompact lattice for q =1 mod 4 in the case that \Delta is Bourdon's building. As a corollary of our constructions, for certain right-angled W and certain q, the lattice \Gamma has a...
Source: http://arxiv.org/abs/1203.2680v2
Arxiv.org
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We demonstrate that the fundamental algebraic structure underlying the Connes-Kreimer Hopf algebra -- the insertion pre-Lie structure on graphs -- corresponds directly to the canonical pre-Lie structure of polynomial vector fields. Using this fact, we construct a Hopf algebra built from tensors that is isomorphic to a version of the Connes-Kreimer Hopf algebra that first appeared in the perturbative renormalization of quantum field theories.
Source: http://arxiv.org/abs/1203.2686v1
Arxiv.org
by Alejandro Cabo Montes de Oca
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A self-consistent formulation is proposed to generalize the HF scheme with the incorporation of screening effects. For this purpose in a first step, an energy functional is defined by the mean value for the full Hamiltonian, not in a Slater determinant state, but in the result of the adiabatic connection of Coulomb plus the nuclear (jellium charge) in the Slater determinant. Afterwards, the energy functional defining the screening approximation is defined in a diagrammatic way, by imposing a...
Source: http://arxiv.org/abs/1203.2689v1
Arxiv.org
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We consider two celebrated criteria for defining the non-classicality of bipartite bosonic quantum systems, the first stemming from information theoretic concepts and the second from physical constraints on the quantum phase-space. Consequently, two sets of allegedly classical states are singled out: i) the set C composed of the so called classical-classical (CC) states---separable states that are locally distinguishable and do not possess quantum discord; ii) the set P of states endowed with a...
Source: http://arxiv.org/abs/1203.2661v2
Arxiv.org
by Gabriele Nebe
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Let $\vartheta := \frac{-1+\sqrt{5}}{2}$ be the golden ratio. A golden lattice is an even unimodular $\Z[\vartheta ]$-lattice of which the Hilbert theta series is an extremal Hilbert modular form. We construct golden lattices from extremal even unimodular lattices and obtain families of dense modular lattices.
Source: http://arxiv.org/abs/1203.2755v1
Arxiv.org
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In this paper we prove that a properly embedded constant mean curvature surface in H^2*R which has finite topology and stays at a finite distance from a vertical geodesic line is invariant by rotation around a vertical geodesic line.
Source: http://arxiv.org/abs/1203.2746v2
Arxiv.org
by M. Gärttner; K. P. Heeg; T. Gasenzer; J. Evers
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We study off resonantly driven disordered gases of Rydberg atoms showing that strong correlation and non-trivial spatial ordering of excitations arise. As an application an implementation of the three-atom CSWAP or Fredkin gate with Rydberg atoms is discussed. The gate not only exploits the Rydberg blockade, but also utilizes the special features of an asymmetric geometric arrangement of the three atoms. We show that continuous-wave off-resonant laser driving alone is sufficient to create...
Source: http://arxiv.org/abs/1203.2884v3
Arxiv.org
by Martin R. Hediger; Luca De Vico; Allan Svendsen; Werner Besenmatter; Jan H. Jensen
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We present a fast computational method to efficiently screen enzyme activity. In the presented method, the effect of mutations on the barrier height of an enzyme-catalysed reaction can be computed within 24 hours on roughly 10 processors. The methodology is based on the PM6 and MOZYME methods as implemented in MOPAC2009, and is tested on the first step of the amide hydrolysis reaction catalyzed by Candida Antarctica lipase B (CalB) enzyme. The barrier heights are estimated using adiabatic...
Source: http://arxiv.org/abs/1203.2950v3
Arxiv.org
by Marin Bertier; Marko Obrovac; Cédric Tedeschi
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With the rise of service-oriented computing, applications are more and more based on coordination of autonomous services. Envisioned over largely distributed and highly dynamic platforms, expressing this coordination calls for alternative programming models. The chemical programming paradigm, which models applications as chemical solutions where molecules representing digital entities involved in the computation, react together to produce a result, has been recently shown to provide the needed...
Source: http://arxiv.org/abs/1203.3013v1
Arxiv.org
by M. Crampin; T. Mestdag; D. J. Saunders
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This paper is concerned with the problem of determining whether a projective-equivalence class of sprays is the geodesic class of a Finsler function. We address both the local and the global aspects of this problem. We present our results entirely in terms of a multiplier, that is, a type (0,2) tensor field along the tangent bundle projection. In the course of the analysis we consider several related issues of interest including the positivity and strong convexity of positively-homogeneous...
Source: http://arxiv.org/abs/1203.3142v1
Arxiv.org
by Michael G. Endres; David B. Kaplan; Jong-Wan Lee; Amy N. Nicholson
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We perform lattice Monte Carlo simulations for up to 66 unitary fermions in a finite box using a highly improved lattice action for nonrelativistic spin 1/2 fermions. We obtain a value of $0.366^{+0.016}_{-0.011}$ for the Bertsch parameter, defined as the energy of the unitary Fermi gas measured in units of the free gas energy in the thermodynamic limit. In addition, for up to four unitary fermions, we compute the spectrum of the lattice theory by exact diagonalization of the transfer matrix...
Source: http://arxiv.org/abs/1203.3169v2
Arxiv.org
by J. M. Almira; Kh. F. Abu-Helaiel
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We study discontinuous solutions of the monomial equation $\frac{1}{n!}\Delta_h^nf(x)=f(h)$. In particular, we characterize the closure of their graph, $\bar{G(f)}^{\mathbb{R}^2}$, and we use the properties of these functions to present a new proof of the Darboux type theorem for polynomials and of Hamel's theorem for additive functions.
Source: http://arxiv.org/abs/1203.3222v1
Arxiv.org
by W. D. Rice; J. Kono; S. Zybell; S. Winnerl; J. Bhattacharyya; H. Schneider; M. Helm; B. Ewers; A. Chernikov; M. Koch; S. Chatterjee; G. Khitrova; H. M. Gibbs; L. Schneebeli; B. Breddermann; M. Kira; S. W. Koch
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We use terahertz pulses to induce resonant transitions between the eigenstates of optically generated exciton populations in a high-quality semiconductor quantum-well sample. Monitoring the excitonic photoluminescence, we observe transient quenching of the $1s$ exciton emission, which we attribute to the terahertz-induced $1s$-to-$2p$ excitation. Simultaneously, a pronounced enhancement of the $2s$-exciton emission is observed, despite the $1s$-to-$2s$ transition being dipole forbidden. A...
Source: http://arxiv.org/abs/1203.3994v2
Arxiv.org
by M. Przanowski; M. Skulimowski; J. Tosiek
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Using the orthodox Weyl -- Wigner -- Stratonovich -- Cohen (WWSC) quantization rule we construct a time -- of -- arrival operator for a free particle on the circle. It is shown that this operator is self -- adjoint but the careful analysis of its properties suggests that it cannot represent a `physical' time -- of -- arrival observable. The problem of a time -- of -- arrival observable for the `waiting screen' is also considered. A method of avoiding the quantum Zeno effect is proposed and the...
Source: http://arxiv.org/abs/1203.4146v1
Arxiv.org
by Iosif Bena; Monica Guica; Wei Song
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We show that the six-dimensional uplift of the five-dimensional Near-Horizon-Extremal-Kerr (NHEK) spacetime can be obtained from an AdS_3 X S^3 solution by a sequence of supergravity - but not string theory - dualities. We present three ways of viewing these pseudo-dualities: as a series of transformations in the STU model, as a combination of Melvin twists and T-dualities and, finally, as a sequence of two generalized spectral flows and a coordinate transformation. We then use these to find an...
Source: http://arxiv.org/abs/1203.4227v1
Arxiv.org
by Ilmar Gahramanov; Tigran Kalaydzhyan; Ingo Kirsch
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We discuss a possible dependence of the chiral magnetic effect (CME) on the elliptic flow coefficient v2. We first study this in a hydrodynamic model for a static anisotropic plasma with multiple anomalous U(1) currents. In the case of two charges, one axial and one vector, the CME formally appears as a first-order transport coefficient in the vector current. We compute this transport coefficient and show its dependence on v2. We also determine the CME-coefficient from first-order corrections...
Source: http://arxiv.org/abs/1203.4259v2
Arxiv.org
by Andreas Schruba; Adam K. Leroy; Fabian Walter; Frank Bigiel; Elias Brinks; W. J. G. de Blok; Carsten Kramer; Erik Rosolowsky; Karin Sandstrom; Karl Schuster; Antonio Usero; Axel Weiss; Helmut Wiesemeyer
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[Abridged] We present maps of CO 2-1 emission covering the entire star-forming disks of 16 nearby dwarf galaxies observed by the IRAM HERACLES survey. The data have 13 arcsec angular resolution, ~250 pc at our average distance of 4 Mpc, and sample the galaxies by 10-1000 resolution elements. We apply stacking techniques to perform the first sensitive search for CO emission in dwarfs outside the Local Group ranging from single lines-of-sight, stacked over IR-bright regions of embedded star...
Source: http://arxiv.org/abs/1203.4231v1
Arxiv.org
by John Gemmer; Shankar Venkataramani
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We investigate the behavior of non-Euclidean plates with constant negative Gaussian curvature using the F\"oppl-von K\'arm\'an reduced theory of elasticity. Motivated by recent experimental results, we focus on annuli with a periodic profile. We prove rigorous upper and lower bounds for the elastic energy that scales like the thickness squared. In particular we show that are only two types of global minimizers -- deformations that remain flat and saddle shaped deformations with isolated...
Source: http://arxiv.org/abs/1203.4329v2
Arxiv.org
by M. Boninsegni; L. Pollet; N. Prokof'ev; B. Svistunov
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Indistinguishability of particles is a major factor destabilizing crystalline order in Bose systems. We describe this effect in terms of damped quasi-particle modes and in the dual language of Feynman paths, and illustrate it by first-principle simulations of dipolar bosons and bulk condensed helium-four. The first major implication is that, contrary to conventional wisdom, zero-point motion alone cannot prevent helium-four crystallization at low temperature, at saturated vapour pressure....
Source: http://arxiv.org/abs/1203.4447v2
Arxiv.org
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We present the results of the symmetry classification of the electron energy bands in graphene and silicene using group theory algebra and the tight--binding approximation. The analysis is performed both in the absence and in the presence of the spin-orbit coupling. We also discuss the bands merging in the Brillouin zone symmetry points and the conditions for the latter to become Dirac points.
Source: http://arxiv.org/abs/1203.4492v8
Arxiv.org
by Mathias Wilke
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In this paper we study a generalized Cahn-Hilliard equation which was proposed by Gurtin. We prove the existence and uniqueness of a local-in-time solution for a quasilinear version, that is, if the coefficients depend on the solution and its gradient. Moreover we show that local solutions to the corresponding semilinear problem exist globally as long as the physical potential satisfies certain growth conditions. Finally we study the long-time behaviour of the solutions and show that each...
Source: http://arxiv.org/abs/1203.4391v1
Arxiv.org
by Zeqian Chen; Chengjun He; Chuangye Liu
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In this paper, we prove the blowup alternative for Gross-Pitaevskii hierarchies on $\mathbb{R}^n$ and give the associated lower bounds on the blowup rate. In particular, we prove that any solution of density operators to the focusing Gross-Pitaevskii hierarchy blow up in finite time for $n \ge 3$ if the energy per some $k$ particles in the initial condition is negative. All of these results hold without the assumption of factorized conditions for initial values as well as the admissible ones....
Source: http://arxiv.org/abs/1203.4411v1
Arxiv.org
by Mark Lacy; Anna Sajina; Susan E. Ridgway; Danielle M. Nielsen; Tanya Urrutia; Duncan Farrah; Elinor L. Gates
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We present preliminary results on fitting of SEDs to 142 z>1 quasars selected in the mid-infrared. Our quasar selection finds objects ranging in extinction from highly obscured, type-2 quasars, through more lightly reddened type-1 quasars and normal type-1s. We find a weak tendency for the objects with the highest far-infrared emission to be obscured quasars, but no bulk systematic offset between the far-infrared properties of dusty and normal quasars as might be expected in the most naive...
Source: http://arxiv.org/abs/1203.4521v1
Arxiv.org
by Paola Bonacini; Maria Grazia Cinquegrani; Lucia Marino
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Let G = (V, E) be a multigraph without loops and for any x {\in}V let E(x) be the set of edges of G incident to x. A homogeneous edge-coloring of G is an assignment of an integer m >= 2 and a coloring c:E {\to} S of the edges of Gsuchthat|S| = mandforanyx{\in}V,if|E(x)| = mqx+rx with0
Source: http://arxiv.org/abs/1203.4531v1
Arxiv.org
by S. Gasparinetti; M. J. Martínez-Pérez; S. de Franceschi; J. P. Pekola; F. Giazotto
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Measuring the temperature of a two-dimensional electron gas at temperatures of a few mK is a challenging issue, which standard thermometry schemes may fail to tackle. We propose and analyze a nongalvanic thermometer, based on a quantum point contact and quantum dot, which delivers virtually no power to the electron system to be measured.
Source: http://arxiv.org/abs/1203.5693v1
Arxiv.org
by N. V. Nitta; Y. Liu; M. L. DeRosa; R. W. Nightingale
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Ground level events (GLEs) occupy the high-energy end of gradual solar energetic particle (SEP) events. They are associated with coronal mass ejections (CMEs) and solar flares, but we still do not clearly understand the special conditions that produce these rare events. During Solar Cycle 23, a total of 16 GLEs were registered, using ground-based neutron monitor data. We first ask if these GLEs are clearly distinguishable from other SEP events observed from space. Setting aside possible...
Source: http://arxiv.org/abs/1203.5777v1
Arxiv.org
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We show that in a background of a sufficiently strong magnetic field the electroweak sector of the quantum vacuum exhibits superconducting and, simultaneously, superfluid properties due to magnetic-field-induced condensation of, respectively, W and Z bosons. The phase transition to the "tandem" superconductor--superfluid phase - which is weakly sensitive to the Higgs sector of the standard model - occurs at the critical magnetic field of 10^{20} Tesla. The superconductor-superfluid...
Source: http://arxiv.org/abs/1203.5963v1
Arxiv.org
by Kazunori Noguchi
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We define the zeta function of a finite category. And we propose a conjecture which states the relationship between the Euler characteristic of finite categories and the zeta function of finite categories. This conjecture is verified when categories are finite groupoids, finite acyclic categories, categories with 2-objects and finite categories satisfying certain condition.
Source: http://arxiv.org/abs/1203.6133v3
Arxiv.org
by Sougata Pal; Simon Oechsner; Boris Bellalta; Miquel Oliver
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Interconnecting multiple sensor networks is a relatively new research field which has emerged in the Wireless Sensor Network domain. Wireless Sensor Networks (WSNs) have typically been seen as logically separate, and few works have considered interconnection and interaction between them. Interconnecting multiple heterogeneous sensor networks therefore opens up a new field besides more traditional research on, e.g., routing, self organization, or MAC layer development. Up to now, some approaches...
Source: http://arxiv.org/abs/1203.6316v2
Arxiv.org
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The three traditional failure classes are system, media, and transaction failures. Sometimes, however, modern storage exhibits failures that differ from all of those. In order to capture and describe such cases, single-page failures are introduced as a fourth failure class. This class encompasses all failures to read a data page correctly and with plausible contents despite all correction attempts in lower system levels. Efficient recovery seems to require a new data structure called the page...
Source: http://arxiv.org/abs/1203.6404v1
Arxiv.org
by Caterina Cocchi; Deborah Prezzi; Alice Ruini; Enrico Benassi; Marilia J. Caldas; Stefano Corni; Elisa Molinari
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The optical excitations of elongated graphene nanoflakes of finite length are investigated theoretically through quantum chemistry semi-empirical approaches. The spectra and the resulting dipole fields are analyzed, accounting in full atomistic details for quantum confinement effects, which are crucial in the nanoscale regime. We find that the optical spectra of these nanostructures are dominated at low energy by excitations with strong intensity, comprised of characteristic coherent...
Source: http://arxiv.org/abs/1203.6369v1
Arxiv.org
by Tullio Ceccherini-Silberstein; Michel Coornaert
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Following ideas developed by Misha Gromov, we investigate surjunctivity and reversibility properties of cellular automata defined over certain concrete categories.
Source: http://arxiv.org/abs/1203.6492v2
Arxiv.org
by Gianluca Geloni; Vitali Kocharyan; Evgeni Saldin
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Self-seeding is a promising approach to significantly narrow the SASE bandwidth of XFELs to produce nearly transform-limited pulses. The development of such schemes in the soft X-ray wavelength range necessarily involves gratings as dispersive elements. These introduce, in general, a pulse-front tilt, which is directly proportional to the angular dispersion. Pulse-front tilt may easily lead to a seed signal decrease by a factor two or more. Suggestions on how to minimize the pulse-front tilt...
Source: http://arxiv.org/abs/1203.6442v1
Arxiv.org
by Carl M. Bender; Daniel W. Hook; S. P. Klevansky
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The non-Hermitian PT-symmetric quantum-mechanical Hamiltonian $H=p^2+x^2(ix)^\epsilon$ has real, positive, and discrete eigenvalues for all $\epsilon\geq 0$. These eigenvalues are analytic continuations of the harmonic-oscillator eigenvalues $E_n=2n+1$ (n=0, 1, 2, 3, ...) at $\epsilon=0$. However, the harmonic oscillator also has negative eigenvalues $E_n=-2n-1$ (n=0, 1, 2, 3, ...), and one may ask whether it is equally possible to continue analytically from these eigenvalues. It is shown in...
Source: http://arxiv.org/abs/1203.6590v1
Arxiv.org
by Anne Mongruel; Thibault Chastel; Evgeny S. Asmolov; Olga I. Vinogradova
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We report measurements of the hydrodynamic drag force acting on a smooth sphere falling down under gravity to a plane decorated with microscopic periodic grooves. Both surfaces are lyophilic, so that a liquid (silicone oil) invades the surface texture being in the Wenzel state. A significant decrease in the hydrodynamic resistance force as compared with that predicted for two smooth surfaces is observed. To quantify the effect of roughness we use the effective no-slip boundary condition, which...
Source: http://arxiv.org/abs/1203.6532v4
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by Frank Aurzada; Thomas Simon
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This article deals with the asymptotic behaviour as $t\to +\infty$ of the survival function $P[T > t],$ where $T$ is the first passage time above a non negative level of a random process starting from zero. In many cases of physical significance, the behaviour is of the type $P[T > t]=t^{-\theta + o(1)}$ for a known or unknown positive parameter $\theta$ which is called a persistence exponent. The problem is well understood for random walks or L\'evy processes but becomes more difficult...
Source: http://arxiv.org/abs/1203.6554v1
Arxiv.org
by Imad Agha; Marcelo Davanco; Bryce Thurston; Kartik Srinivasan
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Low-noise, tunable wavelength-conversion through non-degenerate four-wave mixing Bragg scattering in SiNx waveguides is experimentally demonstrated. Finite element method simulations of waveguide dispersion are used with the split-step Fourier method to predict device performance, and indicate a strong dependence of the conversion efficiency on phase matching, which is controlled by the waveguide geometry. Two 1550 nm wavelength band pulsed pumps are used to achieve tunable conversion of a 980...
Source: http://arxiv.org/abs/1203.6558v2
A search for events with large missing transverse momentum, jets, and at least two tau leptons has been performed using 2 fb^-1 of proton-proton collision data at sqrt(s) = 7 TeV recorded with the ATLAS detector at the Large Hadron Collider. No excess above the Standard Model background expectation is observed and a 95% CL visible cross section upper limit for new phenomena is set. A 95% CL lower limit of 32 TeV is set on the GMSB breaking scale Lambda independent of tan(beta). These limits...
Source: http://arxiv.org/abs/1203.6580v2
Arxiv.org
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In this work we provide a level raising theorem for $\mod \lambda^n$ modular Galois representations. It allows one to see such a Galois representation that is modular of level $N$, weight 2 and trivial Nebentypus as one that is modular of level $Np$, for a prime $p$ coprime to $N$, when a certain local condition at $p$ is satisfied. It is a generalization of a result of Ribet concerning $\mod \ell$ Galois representations.
Source: http://arxiv.org/abs/1203.6541v1
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by Michael J. Wilson; Blake D. Sherwin; J. Colin Hill; Graeme Addison; Nick Battaglia; J. Richard Bond; Sudeep Das; Mark J. Devlin; Joanna Dunkley; Rolando Dunner; Joseph W. Fowler; Megan B. Gralla; Amir Hajian; Mark Halpern; Matt Hilton; Adam D. Hincks; Renee Hlozek; Kevin Huffenberger; John P. Hughes; Arthur Kosowsky; Thibaut Louis; Tobias A. Marriage; Danica Marsden; Felipe Menanteau; Kavilan Moodley; Michael D. Niemack; Michael R. Nolta; Lyman A. Page; Bruce Partridge; Erik D. Reese; Neelima...
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We present a detection of the unnormalized skewness induced by the thermal Sunyaev-Zel'dovich (tSZ) effect in filtered Atacama Cosmology Telescope (ACT) 148 GHz cosmic microwave background temperature maps. Contamination due to infrared and radio sources is minimized by template subtraction of resolved sources and by constructing a mask using outlying values in the 218 GHz (tSZ-null) ACT maps. We measure = -31 +- 6 \mu K^3 (measurement error only) or +- 14 \mu K^3 (including cosmic variance...
Source: http://arxiv.org/abs/1203.6633v2
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by Farook Rahaman; P. K. F. Kuhfittig; Ruhul Amin; Gurudas Mandal; Saibal Ray; Nasarul Islam
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Considering the flat rotation curves as input and treating the matter content in the galactic halo region as quark matter, we have found out a background spacetime metric for the region of the galactic halo. We obtain fairly general conditions that ensure that gravity in the halo region is attractive. We also investigate the stability of circular orbits, along with a different role for quark matter. Bag-model quark matter meeting these conditions therefore provides a suitable model for dark...
Source: http://arxiv.org/abs/1203.6649v2
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by Maciej Rybczynski; Zbigniew Wlodarczyk; Grzegorz Wilk
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It has been noticed recently that transverse momenta (p_T) distributions observed in high energy production processes exhibit remarkably universal scaling behaviour. This is the case when a suitable variable replaces the usual p_T. On the other hand, it is also widely known that transverse momentum distributions in general follow a power-like Tsallis distribution, rather than an exponential Boltzmann-Gibbs, with a (generally energy dependent) nonextensivity parameter q. Here we show that it is...
Source: http://arxiv.org/abs/1203.6787v3
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by Mikhail Isaev; K. V Isaeva
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We study three mixing properties of a graph: large algebraic connectivity, large Cheeger constant (isoperimetric number) and large spectral gap from 1 for the second largest eigenvalue of the transition probability matrix of the random walk on the graph. We prove equivalence of this properties (in some sense). We give estimates for the probability for a random graph to satisfy these properties. In addition, we present asymptotic formulas for the numbers of Eulerian orientations and Eulerian...
Source: http://arxiv.org/abs/1203.6880v1
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by Xavier Waintal; Piet W. Brouwer
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A ferromagnet-normal-metal-ferromagnet trilayer does not conserve spin current and as a result, the conduction electrons can create a torque on the magnetic moments. When the trilayer is connected to a superconducting electrode, the spin torque created by a current flowing perpendicularly to the trilayer can drive the system to a configuration where the two magnetic moments are perpendicular to each other. Here we argue that in contrast to the non-equilibrium torque, the equilibrium torque (or...
Source: http://arxiv.org/abs/cond-mat/0107265v1
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by Giancarlo Franzese
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We consider a frustrated spin model with a glassy dynamics characterized by a slow component and a fast component in the relaxation process. The slow process involves variables with critical behavior at finite temperature T_p and has a global character like the (structural) alpha-relaxation of glasses. The fast process has a more local character and can be associated to the beta-relaxation of glasses. At temperature T>T_p the fast relaxation follows the non-Arrhenius behavior of the slow...
Source: http://arxiv.org/abs/cond-mat/0107491v1
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In this paper various predictions for the scaling exponents of the Nonlocal Kardar-Parisi-Zhang (NKPZ) equation are discussed. I use the Self-Consistent Expansion (SCE), and obtain results that are quite different from result obtained in the past, using Dynamic Renormalization Group analysis (DRG), a Scaling Approach (SA) and a self-consistent Mode Coupling approach (MC). It is shown that the results obtained using SCE recover an exact result for a subfamily of the NKPZ models in one dimension,...
Source: http://arxiv.org/abs/cond-mat/0107476v3
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by N. S. Averkiev; L. E. Golub
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Spin relaxation in-plane anisotropy is predicted for heterostructures based on zinc-blende semiconductors. It is shown that it manifests itself especially brightly if the two spin relaxation mechanisms (D'yakonov-Perel' and Rashba) are comparable in efficiency. It is demonstrated that for the quantum well grown along the [0 0 1] direction, the main axes of spin relaxation rate tensor are [1 1 0] and [1 -1 0].
Source: http://arxiv.org/abs/cond-mat/0107599v1
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by Chris Mihos
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Under the merger hypothesis, elliptical galaxies are built through mergers of gas-rich spirals. However, the relative paucity of HI in most normal ellipticals demands significant processing of atomic gas into other forms if this process is to be viable. Here I present a few qualitative remarks on how the properties of merger-spawned ellipticals might depend on the (evolving) gas content of the progenitor disks, then turn to a more quantitative study of the constraints provided by the nuclear...
Source: http://arxiv.org/abs/astro-ph/0009099v1
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by H. Ebeling; A. C. Edge; J. P. Henry
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We describe the design and current status of a new X-ray cluster survey aimed at the compilation of a statistically complete sample of very X-ray luminous (and thus, by inference, massive), distant clusters of galaxies. The primary goal of the MAssive Cluster Survey (MACS) is to increase the number of known massive clusters at z>0.3 from a handful to hundreds. Upon completion of the survey, the MACS cluster sample will greatly improve our ability to study quantitatively the physical and...
Source: http://arxiv.org/abs/astro-ph/0009101v2
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by D. Martinez-Delgado; A. Aparicio; M. A. Gomez-Flechoso
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We present preliminary results of a long-term project to investigate the process of accretion and tidal disruption of dSph satellites in the Galactic halo and, in particular, to search for new tidal tails in a sample of nearby dSph satellites of the Milky Way. Here we present our finding of extra-tidal debris in the Ursa Minor dS ph and discuss the detection by the Sloan Digitized Sky Survey team of what could be a tidal stream associated to the Sagittarius dSph.
Source: http://arxiv.org/abs/astro-ph/0009066v1
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by L. M. Young; L. van Zee; R. C. Dohm-Palmer; K. Y. Lo
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High spatial and spectral resolution observations of the atomic interstellar medium in nearby dwarf galaxies reveal evidence for warm and cold neutral gas, just like the phases in our own Galaxy. The cold or quiescent phase (about 20% of the HI in the galaxies studied, except for LGS 3) seems to be associated with star formation activity--- it may mark the regions where the conditions are right for star formation. These results help to explain the patterns of star formation activity which are...
Source: http://arxiv.org/abs/astro-ph/0009069v1
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by L. C. Garcia de Andrade
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Density linear perturbations in Einstein-Cartan two fluid cosmologies where the outer model is an isotropic Friedmann solution with closed model while the inner model is a flat anisotropic Einstein-Cartan (EC) cosmology with shear are computed by taking into consideration superhorizon situations.This situation is in agreement with the present isotropy of the Cosmic Background Radiation where the anisotropic EC model evolves into an isotropic general relativistic model.Galaxy formation is...
Source: http://arxiv.org/abs/astro-ph/0009150v1
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A new method for measuring gravitational lensing with high redshift type Ia supernovae is investigated. The method utilizes correlations between foreground galaxies and supernova brightnesses to substantially reduce possible systematic errors and increase the signal to noise ratio. It is shown that this lensing signal can be related to the mass, size and substructure of galaxy halos and galaxy clusters if dark matter consists of microscopic particles. This technique may be particularly useful...
Source: http://arxiv.org/abs/astro-ph/0009197v2
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by Guillaume Dubus; Rita S. J. Kim; Kristen Menou; Paula Szkody; David V. Bowen
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We report on optical spectroscopic observations of the X-ray Transient XTE J1118+480 covering the period from April 7, 2000 to July 4, 2000. The spectrum is characterized by weak, broad, double-peaked Balmer and He lines on top of a blue continuum of slope p ~ 1/3, as expected for an optically-thick accretion disk. The weak Bowen blend seen in our spectra may indicate a low intrinsic metallicity for the source. The presence of a partial S-wave pattern in the HeII lambda-4686 line appears...
Source: http://arxiv.org/abs/astro-ph/0009148v2
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by D. Markovic; F. K. Lamb
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We investigate the suggestion that the frequencies of the kilohertz and other QPOs in the emission from neutron stars in low-mass X-ray binaries are generated by geodesic motion of gas clumps around the star. First we assume, following previous work, that the dominant frequencies produced by such motions are the azimuthal frequency \nuk, the apsidal precession frequency \nuap, and the first overtone of the nodal precession frequency \nunp. We investigate whether geodesics can be found for which...
Source: http://arxiv.org/abs/astro-ph/0009169v2
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by Winfried Zimdahl; Dominik J. Schwarz; Alexander B. Balakin; Diego Pavon
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We explain an accelerated expansion of the present universe, suggested from observations of supernovae of type Ia at high redshift, by introducing an anti-frictional force that is self-consistently exerted on the particles of the cosmic substratum. Cosmic anti-friction, which is intimately related to ``particle production'', is shown to give rise to an effective negative pressure of the cosmic medium. While other explanations for an accelerated expansion (cosmological constant, quintessence)...
Source: http://arxiv.org/abs/astro-ph/0009353v2
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by D. Chicherin; S. Derkachov; D. Karakhanyan; R. Kirschner
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This paper presents the second part of our study devoted to the construction of Baxter operators for the homogeneous closed XXX spin chain with the quantum space carrying infinite or finite-dimensional $s\ell_2$ representations. We consider the Baxter operators used in \cite{BLZ,Shortcut}, formulate their construction uniformly with the construction of our previous paper. The building blocks of all global chain operators are derived from the general Yang-Baxter operators and all operator...
Source: http://arxiv.org/abs/1107.0643v2
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by Ben Hoare; Timothy J. Hollowood; J. Luis Miramontes
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We construct a relativistic scattering theory based on a q deformation and large string tension limit of the magnon S-matrix of the string world sheet theory in AdS_5 x S^5. The S-matrix falls naturally into a previously studied class associated to affine quantum groups, in this case for a twisted affine loop superalgebra associated to an outer automorphism of sl(2|2). This infinite algebra includes the celebrated triply extended psl(2|2) x R^3 algebra, but only two of the centres, the...
Source: http://arxiv.org/abs/1107.0628v2
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In the present paper we prove moderate deviations for a Curie-Weiss model with external magnetic field generated by a dynamical system, as introduced by Dombry and Guillotin-Plantard. The results extend those already obtained in the case of a constant external field by Eichelsbacher and L\"owe. The Curie-Weiss model with dynamic external field is related to the so called dynamic Z-random walks. We also prove a moderate deviation result for the dynamic Z-random walk, completing the list of...
Source: http://arxiv.org/abs/1107.0671v1
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by Joao L. Costa; Artur Alho; Jose Natario
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We apply Christodoulou's framework, developed to study the Einstein-scalar field equations in spherical symmetry, to the linear wave equation in de Sitter spacetime, as a first step towards the Einstein-scalar field equations with positive cosmological constant. We obtain an integro-differential evolution equation which we solve by taking initial data on a null cone. As a corollary we obtain elementary derivations of expected properties of linear waves in de Sitter spacetime: boundedness in...
Source: http://arxiv.org/abs/1107.0802v2
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by Noelia Jiménez; Sofía A. Cora; Lilia P. Bassino; Tomás E. Tecce; Analía V. Smith Castelli
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We investigate the development of the red sequence (RS) of cluster galaxies by using a semi-analytic model of galaxy formation. Results show good agreement between the general trend of the simulated RS and the observed relation in early-type galaxies. However, the most luminous galaxies ($M_V \lesssim -20$) depart from the linear fit to observed data, displaying almost constant colours. We analyze the dependence with redshift of the fraction of stellar mass contributed to each galaxy by...
Source: http://arxiv.org/abs/1107.0722v1
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by Kate A. Ross; Lucile Savary; Bruce D. Gaulin; Leon Balents
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Recent work has highlighted remarkable effects of classical thermal fluctuations in the dipolar spin ice compounds, such as "artificial magnetostatics", manifesting as Coulombic power-law spin correlations and particles behaving as diffusive "magnetic monopoles". In this paper, we address quantum spin ice, giving a unifying framework for the study of magnetism of a large class of magnetic compounds with the pyrochlore structure, and in particular discuss Yb2Ti2O7 and extract...
Source: http://arxiv.org/abs/1107.0761v1
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The common lore in the literature of neutrino mass generation is that the canonical see-saw mechanism beautifully offers an explanation for the tiny neutrino mass but at the cost of introducing right-handed neutrinos at a scale that is out of range for the current experiments. The inverse see-saw mechanism is an interesting alternative to the canonical one once it leads to tiny neutrino masses with the advantage of being testable at TeV scale. However, this last mechanism suffers from an issue...
Source: http://arxiv.org/abs/1107.0739v3
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We theoretically studied the thermally assisted spin torque switching of a synthetic free layer and showed that the switching time is minimized if the condition H_J=|H_s|/(2 alpha) is satisfied, where H_J, H_s and alpha are the coupling field of two ferromagnetic layers, the amplitude of the spin torque, and the Gilbert damping constant. We also showed that the coupling field of the synthetic free layer can be determined from the resonance frequencies of the spin-torque diode effect.
Source: http://arxiv.org/abs/1107.0753v2
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by Wanfeng Yan; Ryan Woodard; Didier Sornette
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We present an extension of the Johansen-Ledoit-Sornette (JLS) model to include an additional pricing factor called the "Zipf factor", which describes the diversification risk of the stock market portfolio. Keeping all the dynamical characteristics of a bubble described in the JLS model, the new model provides additional information about the concentration of stock gains over time. This allows us to understand better the risk diversification and to explain the investors' behavior...
Source: http://arxiv.org/abs/1107.0838v1
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by Philip Boalch
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A new class of isomonodromy equations will be introduced and shown to admit Kac-Moody Weyl group symmetries. This puts into a general context some results of Okamoto on the 4th, 5th and 6th Painleve equations, and shows where such Kac-Moody root systems occur "in nature". A key point is that one may go beyond the class of affine Kac-Moody root systems. As examples, by considering certain hyperbolic Kac-Moody Dynkin diagrams, we find there is a sequence of higher order Painleve systems...
Source: http://arxiv.org/abs/1107.0874v2
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The Leggett mode associated with out-of-phase oscillations of superconducting phase in multi-band superconductors usually is heavy due to the interband coupling, which makes its excitation and detection difficult. We report on the existence of a massless Leggett mode in three-band superconductors with time-reversal-symmetry-breaking (TRSB). The mass of the Leggett mode is small close to the TRSB transition and vanishes at the transition point, and thus locates within the smallest...
Source: http://arxiv.org/abs/1107.0814v2
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by Victor Chepoi; Mark F. Hagen
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We prove that the contact graph of a 2-dimensional CAT(0) cube complex ${\bf X}$ of maximum degree $\Delta$ can be coloured with at most $\epsilon(\Delta)=M\Delta^{26}$ colours, for a fixed constant $M$. This implies that ${\bf X}$ (and the associated median graph) isometrically embeds in the Cartesian product of at most $\epsilon(\Delta)$ trees, and that the event structure whose domain is ${\bf X}$ admits a nice labeling with $\epsilon(\Delta)$ labels. On the other hand, we present an example...
Source: http://arxiv.org/abs/1107.0863v3
Given a chain complex with the only modi?cation that each cell of the complex has a probability distribution assigned. We will call this complex - a random complex and what should be understood in practice, is that we have a classical chain complex whose cells appear and disappear according to some probability distributions. In this paper, we will try to fi?nd the stochastic homology of random complex, whose simplices have independent discrete distributions.
Source: http://arxiv.org/abs/1107.0859v1
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by Jasper van Wezel; Roman Schuster; Andreas König; Martin Knupfer; Jeroen van den Brink; Helmuth Berger; Bernd Büchner
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We investigate the dispersion of the charge carrier plasmon in the three prototypical charge-density wave bearing transition-metal dichalcogenides 2H-TaSe2, 2H-TaS2 and 2H-NbSe2 employing electron energy-loss spectroscopy. For all three compounds the plasmon dispersion is found to be negative for small momentum transfers. This is in contrast to the generic behavior observed in simple metals as well as the related system 2H-NbS2, which does not exhibit charge order. We present a semiclassical...
Source: http://arxiv.org/abs/1107.0892v1
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by Gyan Ranjan; Zhi-Li Zhang
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We explore the geometry of complex networks in terms of an n-dimensional Euclidean embedding represented by the Moore-Penrose pseudo-inverse of the graph Laplacian $(\bb L^+)$. The squared distance of a node $i$ to the origin in this n-dimensional space $(l^+_{ii})$, yields a topological centrality index $(\mathcal{C}^{*}(i) = 1/l^+_{ii})$ for node $i$. In turn, the sum of reciprocals of individual node structural centralities, $\sum_{i}1/\mathcal{C}^*(i) = \sum_{i} l^+_{ii}$, i.e. the trace of...
Source: http://arxiv.org/abs/1107.0989v4
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by Michael Backes; Ian Goldberg; Aniket Kate; Tomas Toft
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Interest in anonymous communication over distributed hash tables (DHTs) has increased in recent years. However, almost all known solutions solely aim at achieving sender or requestor anonymity in DHT queries. In many application scenarios, it is crucial that the queried key remains secret from intermediate peers that (help to) route the queries towards their destinations. In this paper, we satisfy this requirement by presenting an approach for providing privacy for the keys in DHT queries. We...
Source: http://arxiv.org/abs/1107.1072v2
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by Jean Fasel; Richard G. Swan; Ravi A. Rao
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We prove that stably free modules of rank d-1 over a smooth affine algebra of dimension d over an algebraically closed field k are free, provided (d-1)! is nonzero in k.
Source: http://arxiv.org/abs/1107.1051v2
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by Ranch Y. Q. Lai
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We propose a traffic congestion estimation system based on unsupervised on-line learning algorithm. The system does not rely on background extraction or motion detection. It extracts local features inside detection regions of variable size which are drawn on lanes in advance. The extracted features are then clustered into two classes using K-means and Gaussian Mixture Models(GMM). A Bayes classifier is used to detect vehicles according to the previous cluster information which keeps updated...
Source: http://arxiv.org/abs/1107.1058v1
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We show that a smooth, small enough Cauchy datum launches a unique classical solution of the relativistic Vlasov-Darwin (RVD) system globally in time. A similar result is claimed in Comm. Math. Sci. 6, 749-764 (2008) following the work in Int. Mat. Res. Not. 57191, 1-31 (2006). Our proof does not require estimates derived from the conservation of the total energy, nor those previously given on the transverse component of the electric field. These estimates are crucial in the references cited...
Source: http://arxiv.org/abs/1107.0947v2
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by S. Bobrovskyi; W. Buchmuller; J. Hajer; J. Schmidt
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We study supersymmetric extensions of the Standard Model with small R-parity and lepton number violating couplings which are naturally consistent with primordial nucleosynthesis, thermal leptogenesis and gravitino dark matter. We consider supergravity models where the gravitino is the lightest superparticle followed by a bino-like next-to-lightest superparticle (NLSP). Extending previous work we investigate in detail the sensitivity of LHC experiments to the R-parity breaking parameter zeta for...
Source: http://arxiv.org/abs/1107.0926v1
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Let K be a simplicial complex with vertex set V = {v_1,..., v_n}. The complex K is d-representable if there is a collection {C_1,...,C_n} of convex sets in R^d such that a subcollection {C_{i_1},...,C_{i_j}} has a nonempty intersection if and only if {v_{i_1},...,v_{i_j}} is a face of K. In 1967 Wegner proved that every simplicial complex of dimension d is (2d+1)-representable. He also suggested that his bound is the best possible, i.e., that there are $d$-dimensional simplicial complexes which...
Source: http://arxiv.org/abs/1107.1170v1
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by Francesco Cerutti
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We discuss the main features of the recent NNPDF2.1 NLO set, a determination of parton distributions from a global set of hard scattering data using the NNPDF methodology including heavy quark mass effects. We present the implications for LHC observables of this new PDF set. Then we briefly review recent NNPDF progress towards NNLO sets, and in particular the impact of the treatment of fixed target NMC data on NNLO Higgs cross sections.
Source: http://arxiv.org/abs/1107.1095v1
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We discuss various approaches to localization results for one-dimensional random Schr\"odinger operators, both discrete and continuum. We focus in particular on the approach based on F\"urstenberg's Theorem and the Kunz-Souillard method. These notes are based on a series of five one-hour lectures given at University College London in June/July 2011.
Source: http://arxiv.org/abs/1107.1094v1
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by Douglas Natelson; Daniel R. Ward; Falco Hüser; Fabian Pauly; Juan Carlos Cuevas; David A. Corley; James M. Tour
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We use simultaneous electronic transport and optical characterization measurements to reveal new information about electronic and optical processes in nanoscale junctions fabricated by electromigration. Comparing electronic tunneling and photocurrents allows us to infer the optical frequency potential difference produced by the plasmon response of the junction. Together with the measured tunneling conductance, we can then determine the locally enhanced electric field within the junction. In...
Source: http://arxiv.org/abs/1107.1147v1
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by Tsampikos Kottos; Boris Shapiro
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Thermalization of systems described by the discrete non-linear Schr\"odinger equation, in the strong disorder limit, is investigated both theoretically and numerically. We show that introducing correlations in the disorder potential, while keeping the "effective" disorder fixed (as measured by the localization properties of wavepacket dynamics), strongly facilitate the thermalization process and lead to a standard grand canonical distribution of the probability norms associated...
Source: http://arxiv.org/abs/1107.1114v1
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We propose to use Bloch oscillation of ultra-cold atoms in a spin-dependent optical lattice to prepare schrodinger cat states. Depending on its internal state, an atom feels different periodic potentials and thus has different energy band structures for its center-of-mass motion. Consequently, under the same gravity force, the wave packets associated with different internal states perform Bloch oscillation of different amplitudes in space and in particular they can be macroscopically displaced...
Source: http://arxiv.org/abs/1107.0609v2
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by Esther Cabezas-Rivas; Burkhard Wilking
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We prove short time existence for the Ricci flow on open manifolds of nonnegative complex sectional curvature. We do not require upper curvature bounds. By considering the doubling of convex sets contained in a Cheeger-Gromoll convex exhaustion and solving the singular initial value problem for the Ricci flow on these closed manifolds, we obtain a sequence of closed solutions of the Ricci flow with nonnegative complex sectional curvature which subconverge to a solution of the Ricci flow on the...
Source: http://arxiv.org/abs/1107.0606v3
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by Abhik Kumar Sanyal; Claudio Rubano; Ester Piedipalumbo
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Noether symmetry for Gauss-Bonnet-Dilatonic interaction exists for a constant dilatonic scalar potential and a linear functional dependence of the coupling parameter on the scalar field. The symmetry with the same form of the potential and coupling parameter exists all in the vacuum, radiation and matter dominated era. The late time acceleration is driven by the effective cos- mological constant rather than the Gauss-Bonnet term, while the later compensates for the large value of the effective...
Source: http://arxiv.org/abs/1107.0560v1
We propose the consistent statistical approach to consider a wide class of classical open systems whose states are specified by a set of positive integers(occupation numbers).Such systems are often encountered in physics, chemistry, ecology, economics and other sciences.Our statistical method based on ideas of quantum theory of open systems takes into account both discreteness of the system variables and their time fluctuations - two effects which are ignored in usual mean field dynamical...
Source: http://arxiv.org/abs/1107.0548v1
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by S. Groote; J. G. Körner; A. A. Pivovarov
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We compute next-to-leading order (NLO) perturbative QCD corrections to the correlators of interpolating pentaquark currents. We employ modular techniques in configuration space which saves us from the onus of having to do loop calculations. The modular technique is explained in some detail. We present explicit NLO results for several interpolating pentaquark currents that have been written down in the literature. Our modular approach is easily adapted to the case of NLO corrections to...
Source: http://arxiv.org/abs/1107.0615v2
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In order to estimate in absolute terms the luminosity of LHC certain beam parameters have to be measured very accurately. In particular the total beam current and the relative distribution of the charges around the ring, the transverse size of the beams at the interaction points and the relative position of the beams at the interaction point. The experiments can themselves measure several of these parameters very accurately thanks to the versatility of their detectors, other parameters need...
Source: http://arxiv.org/abs/1107.1197v1
We consider a sheared colloidal suspension under the influence of an external potential that varies slowly in space in the plane perpendicular to the flow and acts on one selected (tagged) particle of the suspension. Using a Chapman-Enskog type expansion we derive a steady state equation for the tagged particle density distribution. We show that for potentials varying along one direction only, the tagged particle distribution is the same as the equilibrium distribution with the temperature...
Source: http://arxiv.org/abs/1107.1298v2