The evaluation of Feynman integrals in the physical region using multi-valued approximants
- 1 February 1979
- journal article
- Published by IOP Publishing in Journal of Physics G: Nuclear Physics
- Vol. 5 (2) , 167-198
- https://doi.org/10.1088/0305-4616/5/2/005
Abstract
An extension of the computational technique of Chisolm, Genz, and Putersla (1976) for evaluating Feynman matrix elements in the physical region is presented. The extension is based upon the use of certain multi-valued approximants as a summation method for divergent series; these approximants replace the Pade approximants used previously. The use of these multi-valued approximants enables the singularity structure of Feynman integrals on unphysical sheets to be investigated numerically, and we show that the approximants provide a practical method for the analytic continuation of a function from one Riemann sheet to another. The author also discusses this technique in relation to two-variable approximants and investigate the multi-valued approximants recently defined by Chisholm (1978).Keywords
This publication has 12 references indexed in Scilit:
- On analytic properties of vertex parts in quantum field theoryPublished by Elsevier ,2002
- Multivariate approximants with branch points - II. Off-diagonal approximantsProceedings of the Royal Society of London. Series A. Mathematical and Physical Sciences, 1978
- Multivariate approximants with branch points I. Diagonal approximantsProceedings of the Royal Society of London. Series A. Mathematical and Physical Sciences, 1978
- General rational approximants in N-variablesJournal of Approximation Theory, 1976
- The Generation of Chisholm Rational Polynomial Approximants to Power Series in Two VariablesIMA Journal of Applied Mathematics, 1974
- The convergence of Padé approximants of meromorphic functionsJournal of Mathematical Analysis and Applications, 1970
- Analytic properties of production amplitudesIl Nuovo Cimento (1869-1876), 1961
- Singularities and Discontinuities of Feynman AmplitudesJournal of Mathematical Physics, 1960
- Analytic Properties of Transition Amplitudes in Perturbation TheoryPhysical Review B, 1959
- Calculation of S-matrix elementsMathematical Proceedings of the Cambridge Philosophical Society, 1952