發表於 2013-9-5 10:47:40
题目：Cosmic strings with twisted magnetic flux lines and wound-strings in extra dimensions
报告人：Dr. Mathew J. Lake (Naresuan University，泰国)
摘要：We consider a generalization of the Nielsen-Olesen ansatz, in an abelian-Higgs model with externally coupled charge, which describes strings with twisted magnetic flux lines in the vortex core. The solution does not possess cylindrical symmetry, which leads to the existence of components of conserved momentum, both around the core-axis and along the length of the string. In addition, we consider a model of $F$-strings with rotating, geodesic windings in the compact space of the Klebanov-Strassler geometry and determine matching conditions which ensure energy and momentum conservation when loops chop off from the long-string network. We find that the expressions for the constants of motion, which determine the macroscopic string dynamics, can be made to coincide with those for the twisted flux line string, suggesting that extra-dimensional effects for $F$-strings may be mimicked by field-theoretic structure in topological defects. In particular, three distinct dynamical regimes for loop oscillations emerge, depending on the fraction of the total $F$-string length contained in the compact space or, equivalently, on the fraction of the total flux-line length contained in the B-field windings in the field-theoretic model. The critical case, for which the string becomes effectively tensionless, occurs when this fraction is exactly one half. Finally, the correspondence between the conserved quantities and equations of motion in each model suggest explicit correspondences between individual field theory and string theory parameters, with implications for the distinguishability of extra-dimensional signatures in cosmological or astrophysical observations of cosmic string phenomenology.