String propagation near KaluzaKlein black holes: an analytical and numerical study
Abstract
This paper presents a detailed investigation of the motion of a string near a KaluzaKlein black hole, using the null string expansion. The zerothorder string equations of motion are set up separately for electrically and magnetically charged black hole backgrounds. The case of a string falling headon into the black hole is considered in detail. The equations reduce to quadratures for a magnetically charged hole, while they are amenable to numerical solution for an electrically charged black hole. The KaluzaKlein radius seen by the string as it approaches the black hole decreases in the magnetic case and increases in the electric case. For magnetic backgrounds, analytical solutions can be obtained in terms of elliptical integrals. These reduce to elementary functions in special cases, including that of the wellknown PollardGrossPerrySorkin monopole. Here the string exhibits decelerated descent into the black hole. The results in the authors' earlier papers are substantiated here by presenting a detailed analysis. A preliminary analysis of firstorder perturbations is also presented, and it is shown that the invariant string length receives a nonzero contribution in the first order.
 Publication:

arXiv eprints
 Pub Date:
 August 2000
 arXiv:
 arXiv:hepth/0008166
 Bibcode:
 2000hep.th....8166J
 Keywords:

 High Energy Physics  Theory
 EPrint:
 Latex2e file, 13 pages including three postscript figures