15,311 research outputs found

    Limit Theorems For Quantum Walks Associated with Hadamard Matrices

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    We study a one-parameter family of discrete-time quantum walk models on the line and in the xy-plane associated with the Hadamard walk. Weak convergence in the long-time limit of all moments of the walker's pseudo-velocity on the line and in the xy-plane is proved. Symmetrization on the line and in the xy-plane is theoretically investigated, leading to the resolution of the Konno-Namiki-Soshi conjecture in the special case of symmetrization of the unbiased Hadamard walk on the line . A necessary condition for the existence of a phenomenon known as localization is given

    Regularity and stability of electrostatic solutions in Kaluza-Klein theory

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    We investigate the family of electrostatic spherically symmetric solutions of the five-dimensional Kaluza-Klein theory. Besides black holes and wormholes, a new class of geodesically complete solutions is identified. A monopole perturbation is carried out, enabling us to prove analytically the stability of a large class of solutions, including all black holes and neutral solutions.Comment: 2 pages, "mprocl.sty" with LATEX 2.09, contribution to the 9th Marcel Grossmann meeting (MG9), Rome, July 200

    Electrostatic solutions in Kaluza-Klein theory: geometry and stability

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    We investigate the family of electrostatic spherically symmetric solutions of the five-dimensional Kaluza-Klein theory. Both charged and neutral cases are considered. The analysis of the solutions, through their geometrical properties, reveals the existence of black holes, wormholes and naked singularities. A new class of regular solutions is identified. A monopole perturbation study of all these solutions is carried out, enabling us to prove analytically the stability of large classes of solutions. In particular, the black hole solutions are stable, while for the regular solutions the stability analysis leads to an eigenvalue problem.Comment: Latex file, 21 page

    The Distance of the First Overtone RR Lyrae Variables in the MACHO LMC Database: A New Method to Correct for the Effects of Crowding

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    Previous studies have indicated that many of the RR Lyrae variables in the LMC have properties similar to the ones in the Galactic globular cluster M3. Assuming that the M3 RR Lyrae variables follow the same relationships among period, temperature, amplitude and Fourier phase parameter phi31 as their LMC counterparts, we have used the M3 phi31-logP relation to identify the M3-like unevolved first overtone RR Lyrae variables in 16 fields near the LMC bar. The temperatures of these variables were calculated from the M3 logP-logTe relation so that the extinction could be derived for each star separately. Since blended stars have lower amplitudes for a given period, the period amplitude relation should be a useful tool for identifying which stars are affected by crowding. We find that the low amplitude stars are brighter. We remove them from the sample and derive an LMC distance modulus 18.49+/-0.11.Comment: 30 pages, 7 figures, accepted for publication in the Astronomical Journa

    Capital Expenditure Decisions and the Role of the Not-for-Profit Hospital: An Application of a Social Goods Model

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    Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/68370/2/10.1177_107755879004700404.pd

    Bounds on the force between black holes

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    We treat the problem of N interacting, axisymmetric black holes and obtain two relations among physical parameters of the system including the force between the black holes. The first relation involves the total mass, the angular momenta, the distances and the forces between the black holes. The second one relates the angular momentum and area of each black hole with the forces acting on it.Comment: 13 pages, no figure

    Generalized Massive Gravity and Galilean Conformal Algebra in two dimensions

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    Galilean conformal algebra (GCA) in two dimensions arises as contraction of two copies of the centrally extended Virasoro algebra (t→t,x→ϵxt\rightarrow t, x\rightarrow\epsilon x with ϵ→0\epsilon\rightarrow 0). The central charges of GCA can be expressed in term of Virasoro central charges. For finite and non-zero GCA central charges, the Virasoro central charges must behave as asymmetric form O(1)±O(1ϵ)O(1)\pm O(\frac{1}{\epsilon}). We propose that, the bulk description for 2d GCA with asymmetric central charges is given by general massive gravity (GMG) in three dimensions. It can be seen that, if the gravitational Chern-Simons coupling 1μ\frac{1}{\mu} behaves as of order O(1ϵ\frac{1}{\epsilon}) or (μ→ϵμ\mu\rightarrow\epsilon\mu), the central charges of GMG have the above ϵ\epsilon dependence. So, in non-relativistic scaling limit μ→ϵμ\mu\rightarrow\epsilon\mu, we calculated GCA parameters and finite entropy in term of gravity parameters mass and angular momentum of GMG.Comment: 9 page

    "Importance didactique des conceptions des enseignants tunisiens sur l’éducation à la sexualité dans une perspective citoyenne"- 8th international congress on research in science teaching

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    L’objectif de cette étude est d’analyser les conceptions d'enseignants et futurs enseignants tunisiens et d'identifier les valeurs qu'expriment ces conceptions. Les nombreuses conceptions exprimées sont étudiées en tant qu’interactions entre les connaissances scientifiques, les valeurs et les pratiques d’enseignement, au moyen d’une analyse en composante principale (ACP). L'échantillon est formé de 753 enseignants et futurs enseignants du primaire et du secondaire, qui ont répondu à un questionnaire, dans un contexte strictement contrôlé
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