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