Number 373 (Story #2), May 27, 1998 by Phillip F. Schewe and Ben Stein|
QUANTUM DOT CELLULAR AUTOMATA (QCA) might make possible a new type of transistor-less computing. A quantum dot is essentially a zero-dimensional artificial atom, isolated on (or in ) a semiconductor substrate. Loosing a pair of electrons within a cell of four closely spaced dots (with an appropriate nudge the electrons can tunnel from dot to dot) creates a binary bit: the configuration of the electrons establishes either a 1 or a 0. Put many of these cells together and you have a programmable cellular automata network. Data input and output occurs at the periphery of the cell ensemble, which acts like a neural network in that the computing is performed by the quantum interactions within the array. Wolfgang Porod at Notre Dame (email@example.com, 219-631-6376) reports this week at the APS atomic/molecular/optical physics meeting in Santa Fe on the modeling and operation of a QCA array, including the demonstration, for the first time, of the manipulation of a single electron by another nearby single electron.