This volume constitutes the proceedings of the international conference on "Quantum Information 2003" held in Tokyo University of Science/Tokyo (Japan) from 1 to 3 November 2003, in International Institute for Advanced Studies/Kyoto (Japan) from 5 to 7 November 2003, in University of Waseda/Tokyo (Japan) from 29 to 31 October 2003, in Meijo University/ Nagoya (Japan) from 8 to 9 November 2003. These meetings were organized by the Embassy of Italy in Japan in collaboration with Tokyo University of Science (Tokyo), University of Roma II, International Institute for Advanced Studies, Meijo University (Nagoya) and University of Waseda (Tokyo). We very much appreciate the financial support of the Embassy of Italy in Japan, the Frontier Research Center for Computational Sciences of the Tokyo University of Science, International Institute for Advanced Studies and the universities of Waseda and Meijo.
A study of quantum information has been developed extensively in both sides of the foundation and application in the various fields, but it becomes more and more important but difficult to catch the whole aspects of these fields. In order to understand the latest research of quantum information and to find a future orientation of quantum information, the International Conference entited "Quantum information: mathematical, physical engineering and industrial aspects" was organized by inviting researcheres from mainly Europe and Japan who are actively working on each side of the foundation and application of quantum information. The main purpose of this volume is to emphasize the multidisciplinary aspects in this new and very active field in which concrete technological realizations require the combined efforts of experimental and theoretical physicists, mathematicians and engineers.