5,521 research outputs found

    Theoretical studies of 63Cu Knight shifts of the normal state of YBa2Cu3O7

    Full text link
    The 63Cu Knight shifts and g factors for the normal state of YBa2Cu3O7 in tetragonal phase are theoretically studied in a uniform way from the high (fourth-) order perturbation formulas of these parameters for a 3d9 ion under tetragonally elongated octahedra. The calculations are quantitatively correlated with the local structure of the Cu2+(2) site in YBa2Cu3O7. The theoretical results show good agreement with the observed values, and the improvements are achieved by adopting fewer adjustable parameters as compared to the previous works. It is found that the significant anisotropy of the Knight shifts is mainly attributed to the anisotropy of the g factors due to the orbital interactions.Comment: 5 page

    Investigations of the g factors and local structure for orthorhombic Cu^{2+}(1) site in fresh PrBa_{2}Cu_{3}O_{6+x} powders

    Full text link
    The electron paramagnetic resonance (EPR) g factors g_x, g_y and g_z of the orthorhombic Cu^{2+}(1) site in fresh PrBa_{2}Cu_{3}O_{6+x} powders are theoretically investigated using the perturbation formulas of the g factors for a 3d^9 ion under orthorhombically elongated octahedra. The local orthorhombic distortion around the Cu^{2+}(1) site due to the Jahn-Teller effect is described by the orthorhombic field parameters from the superposition model. The [CuO6]^{10-} complex is found to experience an axial elongation of about 0.04 {\AA} along c axis and the relative bond length variation of about 0.09 {\AA} along a and b axes of the Jahn-Teller nature. The theoretical results of the g factors based on the above local structure are in reasonable agreement with the experimental data.Comment: 6 pages, 1 figur

    QCD Multipole Expansion and Hadronic Transitions in Heavy Quarkonium Systems

    Full text link
    We review the developments of QCD multipole expansion and its applications to hadronic transitions and some radiative decays of heavy quarkonia. Theoretical predictions are compsred with updated experimental results.Comment: 23 pages, 7 figures. Some typos corrected, and 3 references adde

    Prospects for detection of Υ(1D)Υ(1S)ππ\Upsilon(1D) \to \Upsilon(1S) \pi \pi via Υ(3S)Υ(1D)+X\Upsilon(3S) \to \Upsilon(1D) + X

    Full text link
    At least one state in the first family of D-wave bbˉb \bar b quarkonium levels has been discovered near the predicted mass of 10.16 GeV/c2c^2. This state is probably the one with J=2. This state and the ones with J=1 and J=3 may contribute a detectable amount to the decay Υ(1D)Υ(1S)ππ\Upsilon(1D) \to \Upsilon(1S) \pi \pi, depending on the partial widths for these decays for which predictions vary considerably. The prospects for detection of the chain Υ(3S)Υ(1D)+XΥππ+X\Upsilon(3S) \to \Upsilon(1D) + X \to \Upsilon \pi \pi + X are discussed.Comment: 4 pages, LaTeX, 1 figure, to be published in Phys. Rev. D, comment added after Eq. (2

    Analisis Perkembangan Riset Akuntansi Keperilakuan Studi Pada Jurnal Behavioral Research in Accounting (1998-2003)

    Full text link
    This research aims to analyze growth direction of research in journal of BRIA period 1998-2003. Growth analysis is done at topic / article content, research method, and research subject used by writer of article of BRIA 1998-2003. Topic /article content is classified using taxonomy of Birnberg and Shield (1989) which have been modified by Meyer and Rigsby (2001). Technics of descriptive analysis were used to analyze data. The results show that the most frequent topics written in BRIA as long as 1998-2003 is  Accounting Information Processing, Auditing, and Managerial Control. Most research method used are experiment (29 articles) and survey/questionaire/interview (21 articles). Type of subject most often used is accountant /auditor and student S-1. As a whole, this result not far differ from result of research of Meyer and Rigsby (2001). Thereby, until 14 year publication of BRIA, there are not growth mean in the case of topic, method, and used research subject.  This results show that we still have opportunities of doing new research in order to development of behavioral accountancy science. &nbsp

    Gaussian approximations for stochastic systems with delay: chemical Langevin equation and application to a Brusselator system

    Full text link
    We present a heuristic derivation of Gaussian approximations for stochastic chemical reaction systems with distributed delay. In particular we derive the corresponding chemical Langevin equation. Due to the non-Markovian character of the underlying dynamics these equations are integro-differential equations, and the noise in the Gaussian approximation is coloured. Following on from the chemical Langevin equation a further reduction leads to the linear-noise approximation. We apply the formalism to a delay variant of the celebrated Brusselator model, and show how it can be used to characterise noise-driven quasi-cycles, as well as noise-triggered spiking. We find surprisingly intricate dependence of the typical frequency of quasi-cycles on the delay period.Comment: 14 pages, 9 figure

    Finite dimensional quantizations of the (q,p) plane : new space and momentum inequalities

    Get PDF
    We present a N-dimensional quantization a la Berezin-Klauder or frame quantization of the complex plane based on overcomplete families of states (coherent states) generated by the N first harmonic oscillator eigenstates. The spectra of position and momentum operators are finite and eigenvalues are equal, up to a factor, to the zeros of Hermite polynomials. From numerical and theoretical studies of the large NN behavior of the product λ_m(N)λ_M(N)\lambda\_m(N) \lambda\_M(N) of non null smallest positive and largest eigenvalues, we infer the inequality δ_N(Q)Δ_N(Q)=σ_NN<2π\delta\_N(Q) \Delta\_N(Q) = \sigma\_N \overset{<}{\underset{N \to \infty}{\to}} 2 \pi (resp. δ_N(P)Δ_N(P)=σ_NN<2π\delta\_N(P) \Delta\_N(P) = \sigma\_N \overset{<}{\underset{N \to \infty}{\to}} 2 \pi ) involving, in suitable units, the minimal (δ_N(Q)\delta\_N(Q)) and maximal (Δ_N(Q)\Delta\_N(Q)) sizes of regions of space (resp. momentum) which are accessible to exploration within this finite-dimensional quantum framework. Interesting issues on the measurement process and connections with the finite Chern-Simons matrix model for the Quantum Hall effect are discussed
    corecore