We propose three criteria for the generation of random digital strings from quantum beam splitters: (i) three or more mutually exclusive outcomes corresponding to the invocation of three- and higher-dimensional Hilbert spaces, (ii) the mandatory use of pure states in conjugated bases for preparation and detection, and (iii) the use of entangled singlet (unique) states for elimination of bias.

• Received 16 March 2009

DOI:https://doi.org/10.1103/PhysRevA.79.054306