Causality Rules (Second Edition)
Vladimir Pascalutsa · 2024
Causality: Cause and effect. In classical physics, an effect cannot occur before its cause. In Einstein's theory of special relativity, causality means that an effect cannot occur from a cause that is not in the back (past) light cone of that event. The books cover the useful physical relations inferred by unitarity and causality. A famous example is the Kramers–Kronig relation for the refractive index of a gas or dilute medium. For example, chapter 3 generalises the Kramers–Kronig relation to relativistic medium, such as CMB (photon gas). These relations are extensively also used in particle and nuclear physics. Especially useful are the so-called ‘sum rules’, such as the Gerasimov–Drell–Hearn (GDH) or the Baldin sum rule. The author notes that the first edition is too brief. In his teaching practice, he sees that it is challenging to use as a standalone text. He intends to improve the explanations of many topics that students found particularly challenging. The additional material will make the book more timely, self-contained, and logically complete. Key features • Modern book on a timely subject. • Classroom friendly and built on newly developed courses taught at a major physics department in Germany. • Advanced material written in simple non-technical language. • Includes pedagogical examples and discussions of the current forefront research.