The authors describe the electric, magnetic and other relaxational processes in a wide spectrum of materials: liquid crystals, molecular magnets, polymers, high-Tc superconductors and glasses. The book summarizes the phenomenological fundamentals and the experimental methods used. A detailed description of molecular and collective dynamics in the broad range of liquid crystals is presented. Magnetic systems, high-Tc superconductors, polymers and glasses are an important subject of matter. It is shown that the researchers working on relaxation processes in different fields of materials sciences are dealing with the same physical fundamentals, but are sometimes using slightly different terms. The book is addressed to scientists, engineers, graduate and undergraduate students, experimentalists and theorists in physics, chemistry, materials sciences and electronic engineering. Many internationally well known experts contribute to it.

Relaxation Phenomena in Condensed Matter Physics features various methods for spectroscopy techniques presented in this book and the relation of these techniques to correlation functions. This book aims to present the similarities and differences between different studies of the relaxation phenomena and to come up with a unified theoretical approach. This text is divided into two major parts, A and B. Part A deals briefly with several spectroscopy experiments and how they can be analyzed in terms of correlation functions. Spectroscopy techniques are likewise discussed in this part. Part B focuses on the stochastic theory of the said correlation functions, where each stochastic model is situated in the context of a physical process. The result of the calculations is then related to one of the experiments featured in Part A. These stochastic methods provide a simple mathematical framework in analyzing relaxation phenomena that can be related to diffusion process. This book is targeted to graduate students who have already taken quantum and statistical physics and is a good reference to students, scientists, and researchers in the field of condensed matter physics.

This book brings together many different relaxation phenomena in liquids under a common umbrella and provides a unified view of apparently diverse phenomena. It aligns recent experimental results obtained with modern techniques with recent theoretical developments. Such close interaction between experiment and theory in this area goes back to the works of Einstein, Smoluchowski, Kramers' and de Gennes. Development of ultrafast laser spectroscopy recently allowed study of various relaxation processes directly in the time domain, with time scales going down to picosecond (ps) and femtosecond (fs) time scales. This was a remarkable advance because many of the fundamental chemical processes occur precisely in this range and was inaccessible before the 1980s. Since then, an enormous wealth of information has been generated by many groups around the world, who have discovered many interesting phenomena that has fueled further growth in this field. As emphasized throughout the book, the seemingly different phenomena studied in this area are often closely related at a fundamental level. Biman Bagchi explains why relatively small although fairly sophisticated theoretical tools have been successful in explaining a wealth of experimental data at a semi-phenomenological level.

The interaction of sound waves with the medium through which they pass can be used to investigate the thermophysical properties of that medium. With the advent of modern instrumentation, it is now possible to determine the speed and absorption of sound with extremely high precision and, through the dependence of those quantities on variables like temperature, pressure, and frequency to gain a sensitive measure of one or more properties of fluid. This has led to renewed interest in such measurements and in the extraction of thermophysical properties of gases and liquids there from. Physical Acoustics and Metrology of Fluids describes both how to design experiments to achieve the highest possible accuracy and how to relate the quantities measured in those experiments to the thermophysical properties of the medium. A thorough theoretical examination of the alternative experimental methods available is designed to guide the experimentalist toward better and more accurate methods. This theoretical analysis is enhanced and complemented by an in-depth discussion of practical experimental techniques and the problems inherent within them. Bringing together the fields of thermodynamics, kinetic theory, fluid mechanics, and theoretical acoustics, plus a wealth of information about practical instruments, this book represents an essential reference on the design and execution of valuable experiments in fluid metrology and physical acoustics.

The usefulness of the book to the reader is exposure to many different classes of materials and relaxation phenomena. They are tied together by the universal relaxation and diffusion properties they share, and a consistent explanation of their origin. The readers can apply what they learn to solve their own problems and use it as a stepping-stone to make further advances in theoretical understanding of the origin of the universality.