28,984 research outputs found

    Censoring, Factorizations, and Spectral Analysis for Transition Matrices with Block-Repeating Entries

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    In this paper, we use the Markov chain censoring technique to study infinite state Markov chains whose transition matrices possess block-repeating entries. We demonstrate that a number of important probabilistic measures are invariant under censoring. Informally speaking, these measures involve first passage times or expected numbers of visits to certain levels where other levels are taboo;they are closely related to the so-called fundamental matrix of the Markov chain which is also studied here. Factorization theorems for the characteristic equation of the blocks of the transition matrix are obtained. Necessary and sufficient conditions are derived for such a Markov chain to be positive recurrent, null recurrent, or transient based either on spectral analysis, or on a property of the fundamental matrix. Explicit expressions are obtained for key probabilistic measures, including the stationary probability vector and the fundamental matrix, which could be potentially used to develop various recursivealgorithms for computing these measures.block-Toeplitz transition matrices, factorization of characteristic functions, spectral analysis, fundamental matrix, conditions of recurrence and transience.

    Morphological evolution of a 3D CME cloud reconstructed from three viewpoints

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    The propagation properties of coronal mass ejections (CMEs) are crucial to predict its geomagnetic effect. A newly developed three dimensional (3D) mask fitting reconstruction method using coronagraph images from three viewpoints has been described and applied to the CME ejected on August 7, 2010. The CME's 3D localisation, real shape and morphological evolution are presented. Due to its interaction with the ambient solar wind, the morphology of this CME changed significantly in the early phase of evolution. Two hours after its initiation, it was expanding almost self-similarly. CME's 3D localisation is quite helpful to link remote sensing observations to in situ measurements. The investigated CME was propagating to Venus with its flank just touching STEREO B. Its corresponding ICME in the interplanetary space shows a possible signature of a magnetic cloud with a preceding shock in VEX observations, while from STEREO B only a shock is observed. We have calculated three principle axes for the reconstructed 3D CME cloud. The orientation of the major axis is in general consistent with the orientation of a filament (polarity inversion line) observed by SDO/AIA and SDO/HMI. The flux rope axis derived by the MVA analysis from VEX indicates a radial-directed axis orientation. It might be that locally only the leg of the flux rope passed through VEX. The height and speed profiles from the Sun to Venus are obtained. We find that the CME speed possibly had been adjusted to the speed of the ambient solar wind flow after leaving COR2 field of view and before arriving Venus. A southward deflection of the CME from the source region is found from the trajectory of the CME geometric center. We attribute it to the influence of the coronal hole where the fast solar wind emanated from.Comment: ApJ, accepte

    Isoscaling in the Lattice Gas Model

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    The isoscaling behavior is investigated using the isotopic/isobaric yields from the equilibrated thermal source which is prepared by the lattice gas model for lighter systems with A = 36. The isoscaling parameters α\alpha and -β\beta are observed to drop with temperature. The difference of neutron and proton chemical potential shows a turning point around 5 MeV where the liquid gas phase transition occurs in the model. The relative free neutron or proton density shows a nearly linear relation with the N/Z (neutron to proton ratio) of system and the isospin fractionation is observed.Comment: 5 figures, 5 pages; the final version to appear in Phys Rev

    Vacuum induced Berry phases in single-mode Jaynes-Cummings models

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    Motivated by the work [Phys. Rev. Lett. 89, 220404 (2002)] for detecting the vacuum-induced Berry phases with two-mode Jaynes-Cummings models (JCMs), we show here that, for a parameter-dependent single-mode JCM, certain atom-field states also acquire the photon-number-dependent Berry phases after the parameter slowly changed and eventually returned to its initial value. This geometric effect related to the field quantization still exists, even the filed is kept in its vacuum state. Specifically, a feasible Ramsey interference experiment with cavity quantum electrodynamics (QED) system is designed to detect the vacuum-induced Berry phase.Comment: 10 pages, 4 figures

    A Comparison of Quintessence and Nonlinear Born-Infeld Scalar Field Using Gold Supernova data

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    We study the Non-Linear Born-Infeld(NLBI) scalar field model and quintessence model with two different potentials(V(ϕ)=sϕV(\phi)=-s\phi and 1/2m2ϕ2{1/2}m^2\phi^2). We investigate the differences between those two models. We explore the equation of state parameter w and the evolution of scale factor a(t)a(t) in both NLBI scalar field and quintessence model. The present age of universe and the transition redshift are also obtained. We use the Gold dataset of 157 SN-Ia to constrain the parameters of the two models. All the results show that NLBI model is slightly superior to quintessence model.Comment: 17 pages, 10 figures, some references adde

    Study of Radiative Leptonic D Meson Decays

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    We study the radiative leptonic DD meson decays of D^+_{(s)}\to \l^+\nu_{\l}\gamma (\l=e,\mu,\tau), D0ννˉγD^0\to \nu\bar{\nu}\gamma and D^0\to \l^+\l^-\gamma (l=e,μl=e,\mu) within the light front quark model. In the standard model, we find that the decay branching ratios of D(s)+e+νeγD^+_{(s)}\to e^+\nu_e\gamma, D(s)+μ+νμγD^+_{(s)}\to\mu^+\nu_{\mu}\gamma and D(s)+τ+ντγD^+_{(s)}\to\tau^+\nu_{\tau}\gamma are 6.9×1066.9\times 10^{-6} (7.7×1057.7\times 10^{-5}), 2.5×1052.5\times 10^{-5} (2.6×1042.6\times 10^{-4}), and 6.0×1066.0\times 10^{-6} (3.2×1043.2\times 10^{-4}), and that of D^0\to\l^+\l^-\gamma (\l=e,\mu) and D0ννˉγD^0\to\nu\bar{\nu}\gamma are 6.3×10116.3\times 10^{-11} and 2.7×10162.7\times 10^{-16}, respectively.Comment: 23 pages, 6 Figures, LaTex file, a reference added, to be published in Mod. Phys. Lett.
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