Seminar in 20 minutes!
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From: Bowyer, Jude
Sent: 20 January 2010 21:51
To: astro-group; theory-group-seminar; [log in to unmask]
Subject: Cosmology Seminars at Imperial College
Hi all,
Just a reminder that Friday's cosmology seminar will be held in Huxley 503 at 12pm, where Marc Lilley will be talking about:
"Coupled currents in cosmic strings"
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.
Note that we have returned to our previous regular 12pm slot.
See you there!
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