TAG特別講座--弦論入門
本帖最後由 Astrosing 於 2013-8-30 08:36 編輯在現代物理學中，有一門學問試圖把物理學宇宙中五種力統一起來，名為弦論。在這理論中亦把量子力學和廣義相對論結合。本組榮幸地請到前東京大學理學院的早期宇宙學院的硏究員Prof.Matthew Lake 來做講座。歡迎有興趣朋友出席。
在聽本講座前可以先溫習以下內容：
1，微積分
2，Action principle
3. Quantization (at least ,in non relativistic case)
4. Relativity
日期：八月三十一曰星期六
時間：下午兩點半至四點
地點：理工大學EF311室
語言：英文 本帖最後由 iheby 於 2013-8-31 18:56 編輯
:D 會後合照 本帖最後由 Astrosing 於 2013-8-31 22:03 編輯
多謝各位抽空出席，慶幸大家不介意太複習。謝謝Matthew教導。我們日後繼續舉辦類似活動，敬請留意。
聲上
Meeting photos
本帖最後由 Astrosing 於 2013-8-31 22:26 編輯各位朋友，
Dr.Lake 原來有做以下硏究工作。下次他再來請再做報告。
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)
主持人：梁世东 教授
时间：2013年9月10日（周二）下午4:00-5:30
地点：中山大学理工学院十友堂300室
欢迎广大师生参加！
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.
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