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排序方式: 共有399条查询结果,搜索用时 15 毫秒
51.
In this paper,we calculated the B →(J/ψ,ηc) K decays in the perturbative QCD(pQCD) factorization approach with the inclusion of the partial next-to-leading order(NLO) contributions. With the inclusion of the significant enhancement from the NLO vertex corrections,the NLO pQCD predictions for the branching ratios agree with the data within 2σ errors:Br(B0 → J/ψK0) = 5.2-+32..58×10-4,Br(B+ → J/ψK+) = 5.6-+32..79×10-4,Br(B0 →ηcK0) = 5.5-+22..30 × 10-4,Br(B+ →ηcK+) = 5.9-+22..51 × 10-4. 相似文献
52.
We propose an interesting scheme on photon states generation using a fiber optic Mach Zehnder interferometer incorporating a fiber optic ring resonator without any optical pumping parts including in the system, which is available for long-distance link. In principle, the state of a quantum bit, it is known, unknown, or entangled to other systems. The desired quantum states are generated and transmitted in the link via a fiber optic. The transmission quality in terms of quantum fidelity is analyzed, where a high fidelity to the noiseless quantum channel is achieved by adding an ancillary photon after the signal photon within the correlation time of the fiber noise and by performing the quantum parity checking method. The error correction is also analyzed. For simplicity, feature and robustness against path-length mismatches among the nodes make our scheme suitable for multi-user quantum communication networks. 相似文献
53.
Bohui Chen 《数学学报(英文版)》2010,26(2):209-240
The bubble tree compactified instanton moduli space -Mκ (X) is introduced. Its singularity set Singκ(X) is described. By the standard gluing theory, one can show that- Mκ(X) - Singκ(X) is a topological orbifold. In this paper, we give an argument to construct smooth structures on it. 相似文献
54.
Mia Hinnerich 《Applied Mathematical Finance》2013,20(2):94-117
Abstract Empirical evidence confirms that asset price processes exhibit jumps and that asset returns are not Gaussian. We provide a pricing model for equity swaps including quanto equity swaps for a non-Gaussian market. The market is driven by a general marked point process as well as by a standard multidimensional Wiener process. In order to obtain closed-form solutions of the swap values, we assume that all parameters in the asset price processes are deterministic, but possibly functions of time. We derive swap prices using martingale methods rather than replicating portfolios, and we show how to calculate the convexity correction term analytically. Our results are an extension of the results of Liao and Wang (2003; Pricing models of equity swaps, The Journal of Futures Markets, 23(8), pp. 751–772). The martingale method is the key that enables the extension. 相似文献
55.
56.
X. D. Zhang M. L. Guo C. L. Liu L. A. Zhang W. Y. Zhang Y. Q. Ding Q. Wu X. Feng 《The European Physical Journal B - Condensed Matter and Complex Systems》2008,62(4):417-421
A first-principles study has been performed to evaluate the electronic and
optical properties of wurtzite Zn1-xMgxO. Substitutional doping is
considered with Mg concentrations of x = 0, 0.0625, 0.125, 0.1875 and 0.25,
respectively. Mg incorporation can induce band gap widening due to the
decrease of Zn 4s states. The imaginary part of the dielectric function shows
that the optical transition from band edge emission decreases slightly with
increasing Mg contents. The optical band gap also increases from 3.2 to 3.7
eV with increasing Mg contents from 0.0625 to 0.25. The calculated results
suggest that relatively high Mg concentration is necessary for effective
band gap engineering of wurtzite Zn1-xMgxO. 相似文献
57.
G. Bonneau L. C. Costa J. L. Tomazelli 《International Journal of Theoretical Physics》2008,47(6):1764-1775
In this work we reconsider the one loop calculation for the vacuum polarisation tensor in the Lorentz violating quantum electrodynamics.
The electron propagator is “dressed” by a Lorentz breaking extra term in the fermion Lagrangian density. We check gauge invariance
and use the Schwinger–Dyson equation to discuss the full photon propagator. After a discussion on a possible photon mass shift,
we show how a finite quantum correction can be chosen in a unique way in order to ensure—in the spirit of spontaneously broken
theories—the standard normalisation conditions for the vacuum polarisation tensor. Then we comment on possible observable
physical consequences on the Lamb-shift. 相似文献
58.
The vibronic coupling between the first excited S1 (21Ag) and the second excited S2 (11Bu) singlet electronic states in spectroscopy of trans‐1,3,5‐hexatriene molecule is investigated on the basis of a model consisting of two electronic states coupled by two vibrational modes. Employing a perturbation theory that treats the intramolecular couplings in a perturbative manner, the absorption and resonance Raman cross sections and excitation profiles of this molecule are calculated using the time‐correlation function formalism. The non‐Condon corrections are included in evaluation of cross sections. The multidimensional time‐domain integrals that arise in these calculations have been evaluated for the case in which S0 (11Ag) S2 (11Bu) electronic transition takes place between displaced and distorted harmonic potential energy surfaces. The calculated spectra are in good agreement with the experimental ones. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
59.
We calculate the average number of stepsN for edge-to-edge, normal, and indefinitely growing self-avoiding walks (SAWs) on two-dimensional critical percolation clusters, using the real-space renormalization-group approach, with small H cells. Our results are of the formN=AL
D
SAW+B, whereL is the end-to-end distance. Similarly to several deterministic fractals, the fractal dimensionsD
SAW for these three different kinds of SAWs are found to be equal, and the differences between them appear in the amplitudesA and in the correction termsB. This behavior is atributed to the hierarchical nature of the critical percolation cluster. 相似文献
60.
We study the QCD corrections to the calculated values of σ(e+e-→ZH→Zbb), and find that for MH<100 GeV, the process can be measured at the LEP energy to extract information of Higgs and the QCD corrections are negligible, namely the tree-level calculation is sufficiently aciurate for the energy range, while for MH > 100 GeV, the Higgs-involved subprocess can only be investigated at NLC, and then the QCD correction becomes as large as 45%. For MH > 2mt, considering the subprocess e+e-→ZH→Ztt, the QCD corrections are also important and must be taken into account for the cross section evaluation. 相似文献