Number 66 (Story #1), February 3, 1992 by Phillip F. Schewe and Ben Stein QUANTUM CHAOS , where quantum behavior and chaotic behavior overlap, has been demonstrated in experiments involving electrons scattering from small molecules. During the scattering process, an electron travels between the atoms in the molecule as if it were moving through a maze, with numerous possible trajectories that depend sensitively on the electron's starting momentum. The average time for an electron of fixed momentum to escape the maze of atoms was found to vary chaotically with its momentum. Martin C. Gutzwiller of IBM has shown that the variation in the arrival time may be described quantum-mechanically through the mathematical zeta function. This function is used widely in mathematics to describe prime numbers and may someday provide a general description of chaotic behavior in quantum mechanics. (Scientific American, Jan. 1992.)