%0 Journal Article
%T Remote preparation of arbitrary ensembles and quantum bit commitment
%A Hans Halvorson
%J Mathematics
%D 2003
%I arXiv
%R 10.1063/1.1812827
%X The Hughston-Jozsa-Wootters theorem shows that any finite ensemble of quantum states can be prepared "at a distance", and it has been used to demonstrate the insecurity of all bit commitment protocols based on finite quantum systems without superselection rules. In this paper, we prove a generalized HJW theorem for arbitrary ensembles of states on a C*-algebra. We then use this result to demonstrate the insecurity of bit commitment protocols based on infinite quantum systems, and quantum systems with Abelian superselection rules.
%U http://arxiv.org/abs/quant-ph/0310001v2