An introduction to random ßuctuations in the refractive index of air and their effect on optical images, including the impact on MTF. The aim of these notes is to study, in an introductory way, random ßuctuations in the refractive index of air and their effect on optical images. Image quality is measured by a modulation transfer function (MTF) that characterizes the turbulent viewing, and also ...

In a spontaneously broken non-abelian gauge theory, charge conjugation can be a local symmetry. That is, the unbroken gauge group H may contain both a U(1) factor generated by Q, and an element X of the disconnected component of H such that XQX ‘= — Q. Such a model contains topologically-stable cosmic strings with a remarkable property — when a charged particle is transported around the string,...