Small Scale Structure on Relativistic Strings

Cosmological consequences of topological defects such as cosmic strings greatly depend on their macroscopic descriptions. Although described as a Nambu-Goto string microscopically, a cosmic string may not behave as a Nambu -Goto string when viewed at scales of cosmological relevance. A formalism that describes the relativistic motion of a general string in flat Minkowskian spacetime is proposed. It includes the Nambu-Goto equation of motion as a limiting case. The effect of small scale structure on strings, transverse or longitudinal, is studied leading to the development of a set of renormalization group equations for the energy per unit length and the tension of the string. Finally, an extension to n-dimensional objects embedded in (D+1) -dimensional spacetime is presented.