An Introduction To Quantum Fluids

What do atomic nuclei, neutron stars, a domestic power supply, and the stunning colors of stained glass in cathedrals all have in common? The answer lies in the unifying concept of quantum fluids, which allows us to understand the behavior and properties of these different systems in simple terms. This book reveals how quantum mechanics, usually considered as restricted to the invisible microscopic world, in fact plays a crucial role at all scales of the universe. The purpose of the book is to introduce the reader to the fascinating and multifaceted world of quantum fluids, which covers different systems at different scales in the physical world. The first part of the book discusses the notion of phases (solid, liquid, gas), presents basic aspects of the structure of matter and quantum mechanics, and includes some elements of statistical mechanics. The second part provides a description of the major quantum liquids, starting with the paramount case of electron fluids and their many applications in everyday life, followed by liquid helium and atomic nuclei. The authors go on to explore matter at very high densities, covering nuclear matter and compact stars, and the behavior of matter at extremely low temperatures, with the fascinating 'superphases' of superconductivity and superfluidity. The topic of quantum fluids has multidisciplinary applications and this book will appeal to students and researchers in physics, chemistry, astrophysics, engineering and materials science.

The aim of this primer is to cover the essential theoretical information, quickly and concisely, in order to enable senior undergraduate and beginning graduate students to tackle projects in topical research areas of quantum fluids, for example, solitons, vortices and collective modes. The selection of the material, both regarding the content and level of presentation, draws on the authors analysis of the success of relevant research projects with newcomers to the field, as well as of the students feedback from many taught and self-study courses on the subject matter. Starting with a brief historical overview, this text covers particle statistics, weakly interacting condensates and their dynamics and finally superfluid helium and quantum turbulence. At the end of each chapter (apart from the first) there are some exercises. Detailed solutions can be made available to instructors upon request to the authors.

Superconductivity and Quantum Fluids, Volume 29 presents the microscopic theory of superconductivity and superfluidity. This book discusses the characteristics of niobium, which is a type II superconductor. Organized into two parts encompassing eight chapters, this volume begins with an overview of the special Bogoliubov transformation that connects fermions with opposite spins and momenta. This text then describes the collective oscillations of the system in the cases of charged and uncharged particles. Other chapters consider the dynamical system of Fermi particles in a weak external field. This book discusses as well the theoretical explanation of superfluidity, which is as a second, very interesting phenomenon observed at low temperatures. The final chapter illustrates the linearized hydrodynamic equations and explains the mean value expressed in terms of the Fourier components of the retarded Green functions. This book is a valuable resource for physicists. Students and researchers who are interested in the fields of superconductivity and superfluidity will also find this book useful.

The second International Symposium on Quantum Fluids and Solids came to pass during 23-27 Jan. 1977 as the fourth and con cluding part of the seventeenth consecutive running of the Sanibel Symposium Series. With approximately 120 participants from eleven countries (including, for the first time, the USSR), we found it easy to obtain a selection of papers which was fairly comprehen sive. Indeed, our problem was an embarrassment of riches; in spite of our solemn vows not to crowd the schedule, we ended up with an intense program! By far, the majority of the papers pre sented are represented in this volume. We are indebted to many persons and organizations for their contributions to the Symposia. First, we thank Prof. Per-Olov Lowdin, Director of the Quantum Theory Project and originator of the Sanibel Symposia. Without his patient, indulgent cooperation our task would have been vastly more difficult. We are grateful to Prof. F. Eugene Dunnam, Chairman of the Dept. of Physics and Astronomy, for providing Departmental support of our initial or ganlzlng expenses. Approximately one-half of the total cost of the Symposium was borne by a joint grant from the National Science Foundation and the U. S. Air Force Office of Scientific Research. We thank the program officers, Dr. C. Satterthwaite and Dr. D.

The study of quantum fluids, stimulated by the discovery of superfluidity in liquid helium, has experienced renewed interest after the observation of Bose-Einstein condensation (BEC) in ultra-cold atomic gases and the observation a new type of quantum fluid with specific characteristics derived from its intrinsic out-of-equilibrium nature. The main objective of this book is to take a snapshot of the state-of-the-art of this fast moving field with a special emphasis on the hot topics and new trends. Bringing together the most active specialists of the two areas (atomic and polaritonic quantum fluids), we expect that this book will facilitate the exchange and the collaboration between these two communities working on subjects with very strong analogies.

The study of quantum fluids in three dimensions has been an important area for many years as it embraces Bose-Einstein condensation, superfluidity and macroscopic quantisation. These are fundamental aspects of physics which can be studied in liquid 4He. In contrast, quantum fluids in two dimension is more recent and less developed. Nevertheless it has shown many interesting phenomena including a rich variety of phases and the Kosterlitz-Thouless transition. Intermediate between these dimensions are the restricted geometries of micro porous materials into which He may be introduced. The main quantum materials considered are 4He, 3He, D2, H2, H and electrons on the surface of 4He. The superfluid phases of 3He were excluded, e~cept for superfluid film flow, as 3He involves a separate set of problems. These proceedings arise from a lively Advanced Research Workshop on Excitations in Two-Dimensional and Three-Dimensional Quantum Fluids held in Exeter 10-15 August 1990. Fifty scientists took part and each provided a written contribution. Perhaps it is a testimony to the discussions that several papers were revised by the authors after the meeting. The order of the chapters is the same as the presentations at the workshop. This arrangement starts with 4He in three dimensions which establishes a base from which the two dimensional properties can be viewed. At the end of each section there is a report on the discussion session. These are interesting and useful chapters as they clarify points made in the papers and define the boundary of current understanding.

This book provides a unified account of the theory of quantum liquid and discusses the mathematical theory of linear response and correlations. It is helpful for experimental physicists working in the fields of low-temperature or solid-state physics.