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.

Phases, matter and interactions -- Quantum basics -- Ensembles of particles -- Further theoretical aspects -- Electron fluids -- Atoms and molecules -- Nuclei -- High densities -- Superphases

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.

Modern electronic devices and novel materials often derive their extraordinary properties from the intriguing, complex behavior of large numbers of electrons forming what is known as an electron liquid. This book provides an in-depth introduction to the physics of the interacting electron liquid in a broad variety of systems, including metals, semiconductors, artificial nano-structures, atoms and molecules. One, two and three dimensional systems are treated separately and in parallel. Different phases of the electron liquid, from the Landau Fermi liquid to the Wigner crystal, from the Luttinger liquid to the quantum Hall liquid are extensively discussed. Both static and time-dependent density functional theory are presented in detail. Although the emphasis is on the development of the basic physical ideas and on a critical discussion of the most useful approximations, the formal derivation of the results is highly detailed and based on the simplest, most direct methods.

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.