20,092 research outputs found

    The group approach to AdS space propagators: A fast algorithm

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    In this letter we show how the method of [4] for the calculation of two-point functions in d+1-dimensional AdS space can be simplified. This results in an algorithm for the evaluation of the two-point functions as linear combinations of Legendre functions of the second kind. This algorithm can be easily implemented on a computer. For the sake of illustration, we displayed the results for the case of symmetric traceless tensor fields with rank up to l=4.Comment: 14 pages, comment adde

    Alternative Fourier Expansions for Inverse Square Law Forces

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    Few-body problems involving Coulomb or gravitational interactions between pairs of particles, whether in classical or quantum physics, are generally handled through a standard multipole expansion of the two-body potentials. We discuss an alternative based on a compact, cylindrical Green's function expansion that should have wide applicability throughout physics. Two-electron "direct" and "exchange" integrals in many-electron quantum systems are evaluated to illustrate the procedure which is more compact than the standard one using Wigner coefficients and Slater integrals.Comment: 10 pages, latex/Revtex4, 1 figure

    Design of quadrature rules for MĆ¼ntz and MĆ¼ntz-logarithmic polynomials using monomial transformation

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    A method for constructing the exact quadratures for MĆ¼ntz and MĆ¼ntz-logarithmic polynomials is presented. The algorithm does permit to anticipate the precision (machine precision) of the numerical integration of MĆ¼ntz-logarithmic polynomials in terms of the number of Gauss-Legendre (GL) quadrature samples and monomial transformation order. To investigate in depth the properties of classical GL quadrature, we present new optimal asymptotic estimates for the remainder. In boundary element integrals this quadrature rule can be applied to evaluate singular functions with end-point singularity, singular kernel as well as smooth functions. The method is numerically stable, efficient, easy to be implemented. The rule has been fully tested and several numerical examples are included. The proposed quadrature method is more efficient in run-time evaluation than the existing methods for MĆ¼ntz polynomial

    On the derivative of the associated Legendre function of the first kind of integer order with respect to its degree

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    In our recent works [R. Szmytkowski, J. Phys. A 39 (2006) 15147; corrigendum: 40 (2007) 7819; addendum: 40 (2007) 14887], we have investigated the derivative of the Legendre function of the first kind, PĪ½(z)P_{\nu}(z), with respect to its degree Ī½\nu. In the present work, we extend these studies and construct several representations of the derivative of the associated Legendre function of the first kind, PĪ½Ā±m(z)P_{\nu}^{\pm m}(z), with respect to the degree Ī½\nu, for māˆˆNm\in\mathbb{N}. At first, we establish several contour-integral representations of āˆ‚PĪ½Ā±m(z)/āˆ‚Ī½\partial P_{\nu}^{\pm m}(z)/\partial\nu. They are then used to derive Rodrigues-type formulas for [āˆ‚PĪ½Ā±m(z)/āˆ‚Ī½]Ī½=n[\partial P_{\nu}^{\pm m}(z)/\partial\nu]_{\nu=n} with nāˆˆNn\in\mathbb{N}. Next, some closed-form expressions for [āˆ‚PĪ½Ā±m(z)/āˆ‚Ī½]Ī½=n[\partial P_{\nu}^{\pm m}(z)/\partial\nu]_{\nu=n} are obtained. These results are applied to find several representations, both explicit and of the Rodrigues type, for the associated Legendre function of the second kind of integer degree and order, QnĀ±m(z)Q_{n}^{\pm m}(z); the explicit representations are suitable for use for numerical purposes in various regions of the complex zz-plane. Finally, the derivatives [āˆ‚2PĪ½m(z)/āˆ‚Ī½2]Ī½=n[\partial^{2}P_{\nu}^{m}(z)/\partial\nu^{2}]_{\nu=n}, [āˆ‚QĪ½m(z)/āˆ‚Ī½]Ī½=n[\partial Q_{\nu}^{m}(z)/\partial\nu]_{\nu=n} and [āˆ‚QĪ½m(z)/āˆ‚Ī½]Ī½=āˆ’nāˆ’1[\partial Q_{\nu}^{m}(z)/\partial\nu]_{\nu=-n-1}, all with m>nm>n, are evaluated in terms of [āˆ‚PĪ½āˆ’m(Ā±z)/āˆ‚Ī½]Ī½=n[\partial P_{\nu}^{-m}(\pm z)/\partial\nu]_{\nu=n}.Comment: LateX, 40 pages, 1 figure, extensive referencin
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