Coupled currents in cosmic strings

by Marc Lilley (IAP)

Friday 27 Feb 2009, 11:30 → 12:30 Europe/Zurich

Univ. de Geneve, Auditoire 234 (Univ. de Geneve, Auditoire 234)

After an introduction to the single current carrying cosmic string from the field theory side and in Carter's macroscopic description, I will show how both formalisms can be simply extended to a string carrying more than one current. I will then discuss the conditions for stability of the string if transverse and/or longitudinal perturbations of the currents are included. I will also give numerical examples to show that, in the weak coupling limit, the physics of a string carrying several currents is well reproduced by an analytic model in which the worldsheet Lagrangian of each string is approximated - using physical arguments - by, on the one hand, a logarithmic function of two parameters for timelike currents, and by, on the other hand, a rational function of two parameters for spacelike currents.