Download or read book Causality Rules written by Vladimir Pascalutsa and published by Morgan & Claypool Publishers. This book was released on 2018-07-06 with total page 84 pages. Available in PDF, EPUB and Kindle. Book excerpt: Scattering of light by light is a fundamental process arising at the quantum level through vacuum fluctuations. This short book will explain how, remarkably enough, this quantum process can entirely be described in terms classical quantities. This description is derived from general principles, such as causality, unitarity, Lorentz, and gauge symmetries. The reader will be introduced into a rigorous formulation of these fundamental concepts, as well as their physical interpretation and applications.