5,499 research outputs found

    The Rogue Wave and breather solution of the Gerdjikov-Ivanov equation

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    The Gerdjikov-Ivanov (GI) system of qq and rr is defined by a quadratic polynomial spectral problem with 2×22 \times 2 matrix coefficients. Each element of the matrix of n-fold Darboux transformation of this system is expressed by a ratio of (n+1)×(n+1)(n+1)\times (n+1) determinant and n×nn\times n determinant of eigenfunctions, which implies the determinant representation of q[n]q^{[n]} and r[n]r^{[n]} generated from known solution qq and rr. By choosing some special eigenvalues and eigenfunctions according to the reduction conditions q[n]=(r[n])q^{[n]}=-(r^{[n]})^*, the determinant representation of q[n]q^{[n]} provides some new solutions of the GI equation. As examples, the breather solutions and rogue wave of the GI is given explicitly by two-fold DT from a periodic "seed" with a constant amplitude.Comment: 8 figures, 17 page

    Self-consistent tilted-axis-cranking study of triaxial strongly deformed bands in 158^{158}Er at ultrahigh spin

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    Stimulated by recent experimental discoveries, triaxial strongly deformed (TSD) states in 158^{158}Er at ultrahigh spins have been studied by means of the Skyrme-Hartree-Fock model and the tilted-axis-cranking method. Restricting the rotational axis to one of the principal axes -- as done in previous cranking calculations -- two well-defined TSD minima in the total Routhian surface are found for a given configuration: one with positive and another with negative triaxial deformation γ\gamma. By allowing the rotational axis to change direction, the higher-energy minimum is shown to be a saddle point. This resolves the long-standing question of the physical interpretation of the two triaxial minima at a very similar quadrupole shape obtained in the principal axis cranking approach. Several TSD configurations have been predicted, including a highly deformed band expected to cross lesser elongated TSD bands at the highest spins. Its transitional quadrupole moment Qt10.5Q_t \approx 10.5\,eb is close to the measured value of \sim11\,eb; hence, it is a candidate for the structure observed in experiment.Comment: 5 pages, 5 figure

    The cosmological origin of Higgs particles

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    A proposal of the cosmological origin of Higgs particles is given. We show, that the Higgs field could be created from the vacuum quantum conformal fluctuation of Anti-de Sitter space-time, the spontaneous breaking of vacuum symmetry, and the mass of Higgs particle are related to the cosmological constant of our universe,especially the theoretical estimated mass mH_{H} of Higgs particles is mH=2μ2_{H}=\sqrt{-2\mu ^{2}} =Λ/π\sqrt{|\Lambda /\pi}.Comment: 7 pages,no figure

    Litter decomposition in a subtropical plantation in Qianyanzhou, China

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    A long-term (20 months) bulk litter decomposition experiment was conducted in a subtropical plantation in southern China in order to test the hypothesis that stable isotope discrimination occurs during litter decomposition and that litter decomposition increases concentrations of nutrients and organic matter in soil. This was achieved by a litter bag technique. Carbon (C), nitrogen (N) and phosphorus (P) concentrations in the remaining litter as well as delta(13)C and delta(15)N during the experimental period were measured. Meanwhile, organic C, alkali-soluble N and available P concentrations were determined in the soils beneath litter bags and in the soils at the control plots. The dry mass remaining (as % of the initial mass) during litter decomposition exponentially declined (y = 0.9362 e(-0.0365x) , R (2) = 0.93, P < 0.0001), but total C in the remaining litter did not decrease significantly with decomposition process during a 20-month period. By comparison, total N in the remaining litter significantly increased from 5.8 +/- A 1.7 g kg(-1) dw litter in the first month to 10.1 +/- A 1.4 g kg(-1) dw litter in the 20th month. During the decomposition, delta(13)C values of the remaining litter showed an insignificant enrichment, while delta(15)N signatures exhibited a different pattern. It significantly depleted (15)N (y = -0.66x + 0.82, R (2) = 0.57, P < 0.0001) during the initial 7 months while showing (15)N enrichments in the remaining 13 months (y = 0.10x - 4.23, R (2) = 0.32, P < 0.0001). Statistically, litter decomposition has little impact on concentrations of soil organic C and alkali-soluble N and available P in the top soil. This indicates that nutrient return to the topsoil through litter decomposition is limited and that C cycling decoupled from N cycling during decomposition in this subtropical plantation in southern China

    A unified approach to combinatorial key predistribution schemes for sensor networks

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    There have been numerous recent proposals for key predistribution schemes for wireless sensor networks based on various types of combinatorial structures such as designs and codes. Many of these schemes have very similar properties and are analysed in a similar manner. We seek to provide a unified framework to study these kinds of schemes. To do so, we define a new, general class of designs, termed “partially balanced t-designs”, that is sufficiently general that it encompasses almost all of the designs that have been proposed for combinatorial key predistribution schemes. However, this new class of designs still has sufficient structure that we are able to derive general formulas for the metrics of the resulting key predistribution schemes. These metrics can be evaluated for a particular scheme simply by substituting appropriate parameters of the underlying combinatorial structure into our general formulas. We also compare various classes of schemes based on different designs, and point out that some existing proposed schemes are in fact identical, even though their descriptions may seem different. We believe that our general framework should facilitate the analysis of proposals for combinatorial key predistribution schemes and their comparison with existing schemes, and also allow researchers to easily evaluate which scheme or schemes present the best combination of performance metrics for a given application scenario

    CO observations of major merger pairs at z=0: Molecular gas mass and star formation

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    We present CO observations of 78 spiral galaxies in local merger pairs. These galaxies representa subsample of a Ks-band selected sample consisting of 88 close major-merger pairs (HKPAIRs), 44 spiral-spiral (S+S) pairs and 44 spiral-elliptical (S+E) pairs, with separation <20h1<20 h^{-1} kpc and mass ratio <2.5. For all objects, the star formation rate (SFR) and dust mass were derived from HERSCHEL PACS and SPIRE data, and the atomic gas mass, MHI, from the Green Bank Telescope HI observations. The complete data set allows us to study the relation between the gas (atomic and molecular) mass, dust mass and SFR in merger galaxies. We derive the molecular gas fraction (MH2/M*), molecular-to-atomic gas mass ratio (MH2/MHI), gas-to-dust mass ratio and SFE (=SFR/MH2) and study their dependences on pair type (S+S compared to S+E), stellar mass and the presence of morphological interaction signs. We find an overall moderate enhancements (~2x) in both molecular gas fraction (MH2/M*), and molecular-to-atomic gas ratio (MH2/MHI) for star-forming galaxies in major-merger pairs compared to non-interacting comparison samples, whereas no enhancement was found for the SFE nor for the total gas mass fraction (MHI+MH2)/M*. When divided into S+S and S+E, low mass and high mass, and with and without interaction signs, there is a small difference in SFE, moderate difference in MH2/M*, and strong differences in MH2/MHI between subsamples. For MH2/MHI, the difference between S+S and S+E subsamples is 0.69+-0.16 dex and between pairs with and without interaction signs is 0.53+-0.18 dex. Together, our results suggest (1) star formation enhancement in close major-merger pairs occurs mainly in S+S pairs after the first close encounter (indicated by interaction signs) because the HI gas is compressed into star-forming molecular gas by the tidal torque; (2) this effect is much weakened in the S+E pairs.Comment: Accepted in A&A, 19 page
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