Theory of quantum gases and quantum coherence: the Salerno BEC workshop, 3-5 June 2001

This special section of Journal of Physics B: Atomic, Molecular and Optical Physics (J. Phys. B) is a compilation of articles originating from the three day International workshop `Theory of quantum gases and quantum coherence', held earlier this year in Salerno, Italy. The workshop programme was a very successful mixture of topics bringing together colleagues working in different but related areas of research centred about the physics of cold atoms and Bose-Einstein condensation (BEC). It proved to be a very stimulating and interesting event and the organizers would like to thank all of the participants of the workshop and the contributors to this special collection of papers for their enthusiasm and involvement.

The workshop was very unusual both in its goals and its structure. The main aim was to create an environment where young researchers in the theory of ultra-cold quantum gases could present and discuss the results of their studies, both with other young researchers and senior experts in the field, in an informal setting, allowing free criticisms and scientific exchanges. With this objective, the composition of the workshop consisted mainly of PhD students, Post-Doctoral fellows and young research assistants, as well as leading senior scientists. An international advisory committee selected all of the young speakers and we would like to extend our thanks to the members of the committee for their careful selection and support.

Another objective of the workshop was to bring together researchers from such diverse areas as BEC, atom and quantum optics, statistical mechanics and condensed matter physics and provide an opportunity for a fertile cross-breeding of ideas, methods and techniques. The workshop was divided into six different, and more or less homogenous, sessions. Each session was opened and directed by a leading senior scientist in the field of research under discussion. The topics covered during the workshop include microscopic theories of BEC, finite temperature dynamics and critical behaviours, spin squeezing and coherent effects, low dimensional physics, topological objects and exclusion statistics, stochastic methods and kinetic theories, Josephson-like effects and optical lattices, BEC on complex networks, equilibrium and dynamical properties and phase space analysis of trapped Fermi gases and correlation function analysis of recent experiments.

The variety and integrated discussion on these topics is reflected in the papers presented here in this collection. The papers stem from both oral and poster contributions presented at the workshop, as well as additional contributions stimulated by the workshop. They include both topical reviews and original research and have been peer reviewed to the usual high standard of J. Phys. B. We would like to take this opportunity to thank Professor Keith Burnett for supporting this editorial enterprise and the J. Phys. B publishing team both for making its realization possible and for the journal's constant and robust commitment to the physics of quantum gases and fundamental quantum systems. We are impressed and delighted by the continuing progress in this fascinating and rapidly growing new field of research in fundamental physics. The reactions to this little experiment seem to have been largely positive and several colleagues have suggested that the workshop formula should be repeated and extended in the future to include contributions by our fellow experimentalists as well as theoreticians. We thus hope to have a second edition of the workshop very soon, with more young (and not so young!) scientists telling us about their new and exciting discoveries.

Finally we would like to thank all of the institutions and people who have supported the workshop. The European Science Foundation has provided substantial financial support throughout the programme `Quantum Degenerate Dilute Systems: Bose-Einstein Condensation and Beyond (BEC 2000+)'. Our gratitude goes especially to the steering committee of the BEC2000+ programme and to its chairman, Professor Dr Martin Wilkens. The Italian Istituto Nazionale per la Fisica della Materia (INFM) has been another important source of financial support and for this we thank especially the Director of the INFM unit in Salerno, Professor Gianni Costabile. Last but not least we gratefully thank the Faculty of Science, the Department of Physics `E R Caianiello' of the University of Salerno, and its Director, Professor Ferdinando Mancini, for providing a very substantial fraction of the total financial support.