This inaugural volume in a new series on quantum many-body theory contains the papers presented at the Ninth International Conference on Recent Progress in Many-Body Theories. The conference focused on the development and refinement of many-body methods. A major aim was to foster the exchange of ideas among physicists working in such diverse areas as nuclear physics, quantum chemistry, complex systems, lattice Hamiltonians, quantum fluids and condensed matter physics. A special feature was a session devoted to theories for many-electron systems in low-dimensional quantum dots, wires and electrons.

Quantum many-body theory has greatly expanded its scope and depth over the past few years, treating more deeply long-standing issues like phase transitions and strongly-correlated systems, and simultaneously expanding into new areas such as cold atom physics and quantum information. This collection of contributions highlights recent advances in all these areas by leaders in their respective fields. Also included are some historic perspectives by L P Gor'kov and S T Belyaev, Feenberg Medal Recipients at this conference, and Nobel Laureate P W Anderson gives his unique outlook on the future of physics.The volume covers the key topics in many-body theory, tied together through advances in theoretical tools and computational techniques, and a unifying theme of fundamental approaches to quantum many-body physics.

This conference series is now firmly established as one of the premier series of international meetings in the field of many-body physics. The current volume maintains the tradition of covering the entire spectrum of theoretical tools developed to tackle important and current quantum many-body problems. It aims to foster the exchange of ideas and techniques among physicists working in diverse subfields of physics, such as nuclear and sub-nuclear physics, astrophysics, atomic and molecular physics, quantum chemistry, complex systems, quantum field theory, strongly correlated electronic systems, magnetism, quantum fluids and condensed matter physics. The highlights of this book include state-of-the-art contributions to the understanding of supersolid helium, BEC-BCS crossover, fermionic BEC, quantum phase transitions, computing, simulations, as well as the latest results on the more traditional topics of liquid helium, droplets, nuclear and electronic systems. This volume demonstrates the vitality and the fundamental importance of many-body theories, techniques, and applications in understanding diverse and novel phenomena at the cutting-edge of physics. It contains most of the invited talks plus a selection of excellent poster presentations.

Quantum many-body theory as a discipline in its own right dates largely from the 1950's. It has developed since then to its current position as one of the cornerstones of modern theoretical physics. The field remains vibrant and active, vigorous and exciting. Its most powerful techniques are truly universal. They are constantly expanding to find new fields of application, while advances continue to be made in the more traditional areas. To commemorate the impending 80th birthdays of its two co-inventors, Firtz Coester and Hermann Kümmel, one such technique, namely the coupled cluster method, was especially highlighted at this meeting, the eleventh in the series of International Conferences on Recent Progress in Many-Body Theories. The history of the coupled cluster method as told here mirrors in many ways both the development of the entire discipline of microscopic quantum many-body theory and the history of the series of conferences. The series itself is universally recognised as being the premier series of meetings in this subject area. Its proceedings have always summarised the current state of the art through the lectures of its leading practitioners. The present volume is no exception. No serious researcher in quantum many-body theory or in any field which uses it can afford to be without this volume.

This volume contains the main contributions to the 14th International Conference on Recent Progress in Many-Body Theories (RPMBT14) held at the Technical University of Catalonia, Spain, in July 2007. This conference, which was first held in Trieste in 1979, is devoted to new developments in the field of many-body theories, which are being applied and developed in a rapidly growing number of fields. The emphasis is twofold: progress in the technical aspects of microscopic theories and a review of recent applications of many-body techniques. In addition to the more traditional topics, such as nuclear physics and quantum liquids, the present volume also includes the most recent results on atomic physics, cold Bose and Fermi gases, phase transitions and quantum information. Moreover, the volume contains the lectures of the winners of the 2007 Feenberg Medal and 2007 Kuemmel Award, as well as their laudatios.

Quantum many-body theory as a discipline in its own right dates largely from the 1950's. It has developed since then to its current position as one of the cornerstones of modern theoretical physics. The field remains vibrant and active, vigorous and exciting. Indeed, its successes and importance were vividly illustrated prior to the conference by the sharing of the 1998 Nobel Prizes in both Physics and Chemistry by three many-body theorists. Two of those Nobel laureates, Walter Kohn and Bob Laughlin, delivered invited lectures at this meeting, the tenth in the series of International Conferences on Recent Progress in Many-Body Theories. This series is universally recognized as being the premier series of meetings on this subject, and its proceedings have always summarized the current state of the art through the lectures of its leading practitioners. The present volume is no exception.A major aim of this conference series has been to foster the exchange of ideas between physicists working in all the diverse fields of application of quantum many-body theory. These include nuclear and subnuclear physics, quantum fluids, strongly correlated electronic systems, and low-dimensional condensed-matter systems and materials. All of these fields and others are represented in the present volume. Other topical themes covered include density functional theory and its applications to nuclear and electronic systems, quantum dots and chaos, and trapped Bose-Einstein condensates. Through this breadth of applications the reader will get a clear illustration of the power of the tools of modern microscopic quantum many-body theory, and their usefulness both in achieving a commonality of approach and understanding, and in transferring powerful ideas from one field to another.

Quantum many-body theory as a discipline in its own right dates largely from the 1950's. It has developed since then to its current position as one of the cornerstones of modern theoretical physics. The field remains vibrant and active, vigorous and exciting. Its most powerful techniques are truly universal. They are constantly expanding to find new fields of application, while advances continue to be made in the more traditional areas.