Recursive algorithm for arrays of generalized Bessel functions: Numerical access to Dirac-Volkov solutions

Phys Rev E Stat Nonlin Soft Matter Phys. 2009 Feb;79(2 Pt 2):026707. doi: 10.1103/PhysRevE.79.026707. Epub 2009 Feb 27.

Abstract

In the relativistic and the nonrelativistic theoretical treatment of moderate and high-power laser-matter interaction, the generalized Bessel function occurs naturally when a Schrödinger-Volkov and Dirac-Volkov solution is expanded into plane waves. For the evaluation of cross sections of quantum electrodynamic processes in a linearly polarized laser field, it is often necessary to evaluate large arrays of generalized Bessel functions, of arbitrary index but with fixed arguments. We show that the generalized Bessel function can be evaluated, in a numerically stable way, by utilizing a recurrence relation and a normalization condition only, without having to compute any initial value. We demonstrate the utility of the method by illustrating the quantum-classical correspondence of the Dirac-Volkov solutions via numerical calculations.