Null Strings in Schwarzschild Spacetime

• Main Authors: Dabrowski, Mariusz P., Larsen, Arne. L.
• Format: Text
• Language: unknown
• Published: arXiv 1996
• Subjects: High Energy Physics - Theory hep-th; General Relativity and Quantum Cosmology gr-qc; FOS Physical sciences; North Pole; South Pole; South pole
• Online Access: https://dx.doi.org/10.48550/arxiv.hep-th/9610243; https://arxiv.org/abs/hep-th/9610243

The null string equations of motion and constraints in the Schwarzschild spacetime are given. The solutions are those of the null geodesics of General Relativity appended by a null string constraint in which the "constants of motion" depend on the world-sheet spatial coordinate. Because of the extended nature of a string, the physical interpretation of the solutions is completely different from the point particle case. In particular, a null string is generally not propagating in a plane through the origin, although each of its individual points is. Some special solutions are obtained and their physical interpretation is given. Especially, the solution for a null string with a constant radial coordinate $r$ moving vertically from the south pole to the north pole around the photon sphere, is presented. A general discussion of classical null/tensile strings as compared to massless/massive particles is given. For instance, tensile circular solutions with a constant radial coordinate $r$ do not exist at all. The results are discussed in relation to the previous literature on the subject. : 16 pages, REVTEX, no figures