Shifts on a finite qubit string: A class of quantum baker's maps
  We present two complementary ways in which Saraceno's symmetric version of the quantum baker's map can be written as a shift map on a string of quantum bits. One of these representations leads naturally to a family of quantizations of the baker's map. 
R. Schack (Royal Holloway, University of London), C. M. Caves   (University of New Mexico)