PHYSICS NEWS UPDATE
The American Institute of Physics Bulletin of Physics News
Number 389 September 4, 1998 by Phillip F. Schewe and Ben
Stein
CHAOS-BASED COMPUTING, a fundamentally new way to perform computations by exploiting the ubiquitous phenomenon of chaos, has been demonstrated in a simulation by researchers in India and the United States (Bill Ditto, Georgia Tech, 404-894-5216). Compared to digital computation, the chaos-based technique might come closer to how the brain performs computation, and might be superior in certain tasks such as pattern recognition. The computer consists of an interconnected grid of "chaotic elements," systems such as ammonia lasers which can generate unpredictable signals even though their behavior is governed by known mathematical equations. To encode specific numbers into each element, the researchers make specific signal patterns correspond to a number and ask each element to open its connection to the rest of the grid when it generates that pattern. Sending its signal out to the grid can trigger activity in neighboring elements. To carry out specific operations such as addition, the researchers connect the elements in a certain way. An unpredictable but deterministic avalanche of activity among the elements ultimately settles down to produce an unvarying signal that corresponds to the desired answer. Having demonstrated their technique in a computer simulation, the researchers are planning to test this idea with chaotic ammonia lasers and hybrid networks of nerve cells and silicon chips. (Sinha and Ditto, Physical Review Letters, 7 September 1998.)