Elementary Excitations In Quantum Fluids

This volume is the proceedings of the Hiroshima Symposium on Elementary Excitations in Quantum Fluids, which was held on August 17 and 18, 1987, in Hiroshima, Japan, and was attended by thirty-two scientists from seven countries. Quantum fluids have been the subject of intense study as a consequence of their superfluid properties at very low temperatures. Elementary excitations in them are an important concept about which many important discoveries have been made in recent years. This symposium was arranged by a group of physicists from Hiroshima University to provide an opportunity to discuss these recent developments. It was conceived as a satellite conference of the 18th International Conference on Low Temperature Physics (LT 18), which was held in Kyoto, August 20-26, 1987. Emphasis was placed on the dynamic structures and correlations of ele mentary excitations, which resulted in invited speakers being selected from this field. However, enthusiastic contributors reported notable new results on various other aspects of the elementary excitations, which made the sympo sium lively and successful. It is our great satisfaction to present this volume, which includes papers of good quality and originality. We thank all the parti cipants for their cooperation throughout this symposium, and for preparing their manuscripts within a reasonable time.

Theory of Quantum Fluids is a concise report on the microscopic description of liquid 4He and liquid 3He in the physical density range using simple forms of the potential function between pairs of neutral atoms and the properties of the ground states and limited ranges of low excited states. The monograph covers the properties of the radial distribution function and the three-particle distribution particle; the classical sound field and the correspondence principle; paired phonon states in the free- phonon approximation; the uniform limit and the charged boson system; and the microscopic theory of a single 3He atom in the 4He liquid. Theoretical and experimental physicists will find the book very interesting.

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.

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.

This volume is devoted to the theory of superfluid quantum liquids, describing the Landau theory of a neutral Fermi liquid in order to illustrate, in comparatively elementary fashion, the way both quantum statistics and particle interaction determine system behavior.

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 is an introduction to the physics of elementary excitations in condensed matter with emphasis on basic concepts and their mathematical representations. The nature of the book is mainly determined by the fact that it was originally written, in Japanese, as one volume of Iwanami Series of Fundamental Physics supervised by Professor H. Yukawa. Our task was to portray the theory of condensed matter from a unified point of view for the student looking for his own research field and also for more senior readers interested in fundamentals of contemporary physics. As our point of view, we chose the concept of elementary excitation, which we believe to be one of the most fruitful concepts discovered by the quantum theory of matter. The present English edition has been translated by the authors themselves from the second, revised Japanese edition published in 1978, six years after publication of the first edition. In translating, we have introduced no major modifications; only the list of references has been made more suitable to overseas readers. In the English as well as in the Japanese editions, Chaps. 1,4, and part of 6 were written by Nakajima, Chaps. 2, 5, and 7 by Toyozawa, and Chaps. 3 and part of 6 by Abe. Finally we should like to thank Professor P. Fulde for kind help and Dr. H. Lotsch, SpriIiger-Verlag, for patient cooperation in making this English edition a reality.

Originally published as two separate volumes, The Theory of Quantum Liquids is a classic text that attempts to describe the qualitative and unifying aspects of an extremely broad and diversified field. Volume I deals with ‘normal' Fremi liquids, such as 3He and electrons in metals. Volume II consists of a detailed treatment of Bose condensation and liquid 4He, including the development of a Bose liquid theory and a microscopic basis for the two-fluid model, and the description of the elementary excitations of liquid HeII.

This book is concerned with a single group of quantum liquids, normal Fermi liqztids, discussing the nature of elementary excitations, the central concept of response functions. It is intended as a text for a graduate course in quantum statistical mechanics or low temperature theory.