Physics of Low-dimensional Systems: Nobel Symposium 73

Abstract

The physics of low-dimensional systems has developed in a remarkable way over the last decade and has accelerated over the last few years, in particular because of the discovery of the new high temperature superconductors. The new developments started more than fifteen years ago with the discovery of the unexpected quasi-one-dimensional character of the TTF-TCNQ. Since then the field of conducting quasi-one-dimensional organic systems have been rapidly growing. Parallel to the experimental work there has been an important theoretical development of great conceptual importance, such as charge density waves, soliton-like excitations, fractional charges, new symmetry properties etc. A new field of fundamental importance was the discovery of the Quantum Hall Effect in 1980. This field is still expanding with new experimental and theoretical discoveries. In 1986, then, came the totally unexpected discovery of high temperature superconductivity which started an explosive development.The three areas just mentioned formed the main themes of the Symposium. They do not in any way exhaust the progress in low-dimensional physics. We should mention the recent important development with both two-dimensional and one-dimensional and even zero-dimensional structures (quantum dots). The physics of mesoscopic systems is another important area where the low dimensionality is a key feature. Because of the small format of this Symposium we could unfortunately not cover these areas.A Nobel Symposium provides an excellent opportunity to bring together a group of prominent scientists for a stimulating exchange of new ideas and results. The Nobel Symposia are very small meetings by invitation only and the number of key international participants is typically in the range 25–40. These Symposia are arranged through a special Nobel Symposium Committee after proposal from individuals. This Symposium was sponsored by the Nobel Foundation through its Nobel Symposium Fund with grants from The Tercentenary Fund of the Bank of Sweden and The Knut and Alice Wallenberg Foundation. Additional support was obtained from the Royal Academy of Sciences, the Nordic Institute for Theoretical Atomic Physics (NORDITA), Chalmers University of Technology and Gothenburg University.To arrange a Nobel Symposium on such hot topics is an open invitation for criticism and trouble. The organizers tried their best to select a few topics of current interest in order to generate a strong interaction between participants and to stimulate a good discussion. I would like to express our apologies to all these prominent scientists who could not be invited because of the small format of the Symposium and the planning of the organizers.These Proceedings contain most of the material presented at the Symposium. A few participants found it inconvenient to prepare a full length paper, which would just have been a modified version of material to appear in regular journals. Others might have felt that a conference proceeding be too slow a medium in comparison with e.g. the New York Times. On the whole however these proceedings give a good report of the science discussed during the Symposium.We would like to place on record our sincere thanks to the participants who contributed substantially in the planning by making valuable suggestions about participants and topics. In particular, Bob Schrieffer did a great job in organizing the programme and effectively to run the Symposium. My co-organizers played a crucial role in the planning and during the Symposium week. Our secretary, Yvonne Steen, deserves our very special thanks for her outstanding work.I would finally like to say something about Gräftåvallen and our hosts, Annica and Tommy Hagström. We decided to take the Symposium out of academia and chose this charming tiny mountain resort on a mountain slope in the northern Swedish mountains about 20 miles from the nearest village. Annica and Tommy Hagström welcomed us with such warm hospitality and offered us throughout the week the very best of the local mountain delicacies. Also the local community greeted us as some very special guests and arranged an evening programme at a nearby shieling with goats, sheep, dairy maids, folk music and folk dancing. They also arranged a wonderful concert in their beautiful church from the 12th century.We, the organizers, experienced this symposium as a scientific event with an excellent discussion of the progress in these fields thanks to the outstanding contributions of the participants. We hope that these Proceedings will convey to the reader something of the excitement felt during the symposium week.