This book introduces the main concepts of nonequilibrium phenomena in superconductors. The authors cover both experimentally well-understood topics and problems which physicists could challenge more in view of current theoretical understanding. Some of these topics include thermoelectric phenomena, influence of laser radiation as well as fluctuations in superconductors.

The importance of phonons has long been recognized by research ers in nonequilibrium superconductivity. Similarly, experimentalists studying phonons at low temperatures have relied heavily on supercon ductors as sources and detectors. To a large extent this symbiotic relationship has developed with a general mutual awareness; however, to our knowledge these subjects have never been treated together in conferences or study institutes. It was with the hope of further contributing to the awareness and communication between workers in these areas that this NATO Advanced Study Institute (ASI) has been conceived. A second, but equally important, reason for holding this ASI is to fill a void by providing the first general textbook in this important area of physics. Therefore, there was an emphasis on the tutorial nature of the lectures and written contributions to this textbook. It should not go unnoticed that the experimental and theoretical concepts covered in this textbook are of paramount importance to the various applications of superconductors. Almost by definition, the use of a superconductor implies a nonequilibrium state! For example, phonon conduction to the helium bath is important in devices ranging from microscopic Josephson junctions to large scale magnets and transmission lines. Knowledge of the more fundamental nonequilibrium effects can aid in our understanding of devices as well as provide the potential for entirely new applications.

The physics of nonequilibrium electrons and phonons in semiconductors is an important branch of fundamental physics that has many practical applications, especially in the development of ultrafast and ultrasmall semiconductor devices. This volume is devoted to different trends in the field which are presently at the forefront of research. Special attention is paid to the ultrafast relaxation processes in bulk semiconductors and two-dimensional semiconductor structures, and to their study by different spectroscopic methods, both pulsed and steady-state. The evolution of energy and space distribution of nonequilibrium electrons and the relaxation kinetics of hot carriers and phonons are considered under various conditions such as temperature, doping and pumping intensity by leading experts in the field.

This accessible textbook offers a novel, concept-led approach to superconducting electronics, using the COMSOL Multiphysics software to help describe fundamental principles in an intuitive manner. Based on a course taught by the author and aimed primarily at engineering students, the book explains concepts effectively and efficiently, uncovering the “shortcut” to understanding each topic, enabling readers to quickly grasp the underlying essence. The book is divided into two main parts; the first part provides a general introduction to key topics encountered in superconductivity, illustrated using COMSOL simulations based on time-dependent Ginzburg-Landau equations and avoiding any deeply mathematical derivations. It includes numerous worked examples and problem sets with tips and solutions. The second part of the book is more conventional in nature, providing detailed derivations of the basic equations from first principles. This part covers more advanced topics, including the BCS-Gor'kov-Eliashberg approach to equilibrium properties of superconductors, the derivation of kinetic equations for nonequilibrium superconductors, and the derivation of time-dependent Ginzburg–Landau equations, used as the basis for COMSOL modeling in the first part. Supported throughout by an extensive library of COMSOL Multiphysics animations, the book serves as a uniquely accessible introduction to the field for engineers and others with a less rigorous background in physics and mathematics. However, it also features more detailed mathematical background for those wishing to delve further into the subject.