Introduction

This introduction presents an overview of the key concepts discussed in the subsequent chapters of this book. The book introduces the basic idea of the effective superfluid wavefunction. It explains the simplest macroscopic quantum phenomena associated with super fluids, such as the Meissner effect, the magnetic skin depth and the quantization of trapped flux. The book covers the basic aspects of superconductivity which involve only the thermodynamic and superfluid properties. It also covers the basic properties of the high-temperature cuprate superconductors. The book is concerned with the full microscopic theory. It extends to the experimental phenomena which are best discussed in the context of microscopic theory, including the transport and high-frequency properties of the superconducting state, tunnelling through barriers, the proximity effect, normal-superconducting (ns) boundary physics and non-equilibrium effects. The book compares the cuprates with bcs theory. It suggests some of the ideas which appear in microscopic theory.