Exotic phenomena in non-Abelian gauge theories

Author: Lo, Hoi-Kwong

Year: 1994

Degree: Dissertation (Ph.D.)

Advisor: Preskill, John P.

Committee Member: Unknown, Unknown

Option: Physics

DOI: 10.7907/zb83-8m77

Abstract

This thesis deals with some exotic phenomena in non-Abelian gauge theories. More specifically, we study aspects of non-Abelian vortices, non-Abelian Chern-Simons particles, wormhole physics and electroweak strings. Non-Abelian vortices are capable of carrying charges without apparent sources (Cheshire charge). They obey exotic statistics—they generally form irreducible representations of the braid groups of dimensions larger than one. Owing to topological interactions, two vortices scatter non-trivially with each other even in the absence of any classical forces. As a function of the scattering angle, the exclusive cross-section for the vortex-vortex scattering process in the "group eigenstates" is generally multi-valued. Moreover, there can be an exchange contribution even if the two vortices have distinct initial quantum numbers. Thus, two vortices can be indistinguishable without being the same! We also construct exact wave functions for systems of non-Abelian Chern-Simons particles. In wormhole physics, we analyze the measurements of charge and magnetic flux in a wormhole background and show that they are complementary observables. For one thing, this investigation illustrates clearly how charge is conserved in the presence of a wormhole. Finally, we discuss the scattering of fermions from an electroweak string.

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