SÉMINAIRE DU GRECO
"Coupled currents in cosmic strings" |
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M. Lilley |
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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 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. |
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lundi 27 avril 2009 - 11:00 Salle des séminaires Évry Schatzman, Institut d'Astrophysique de Paris |
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