What is a Chemical Computer…?
A chemical computer also called reaction-diffusion computer or BZ computer is an unconventional computer based on a semi-solid chemical "soup" where data is represented by varying concentrations of chemicals. The computations are performed by naturally occurring chemical reactions. So far it is still in a very early experimental stage, but may have great potential for the computer industry.
The simplicity of this technology is one of the main reasons why it in the future could turn into a serious competitor to machines based on conventional hardware. A modern microprocessor is an incredibly complicated device that can be destroyed during production by no more than a single airborne microscopic particle. In contrast a cup of chemicals is a simple and stable component that is cheap to produce.
In a conventional microprocessor the bits behave much like cars in city traffic; they can only use certain roads, they have to slow down and wait for each other in crossing traffic, and only one driving field at once can be used. In a BZ solution the waves are moving in all thinkable directions in all dimensions, across, away and against each other. These properties might make a chemical computer able to handle billions of times more data than a traditional computer. An analogy would be the brain; even if a microprocessor can transfer information much faster than a neuron, the brain is still much more effective for some tasks because it can work with a much higher amount of data at the same time.
Modern Research
In 1989 it was demonstrated how light-sensitive chemical reactions could perform image processing. This led to an upsurge in the field of chemical computing. Andrew at the University of the West of England has demonstrated simple logic gates using reaction-diffusion processes. Furthermore he has theoretically shown how a hypothetical "2+ medium" modeled as a cellular automaton can perform computation.
The breakthrough came when he read a theoretical article of two scientists who illustrated how to make logic gates to a computer by using the balls on a billiard table as an example. Like in the case with the AND-gate, two balls represents two different bits. If a single ball shoots towards a common colliding point, the bit is 1. If not, it is 0. A collision will only occur if both balls are sent toward the point, which then is registered in the same way as when two electronic 1's gives a new and single 1. In this way the balls work together like an AND-gate. Adamatzkys' great achievement was to transfer this principle to the BZ-chemicale and replace the billiard balls with waves. If it occurs two waves in the solution, they will meet and create as a third wave which is registered as a 1. He has tested the theory in practice and has already documented that it works. For the moment he is cooperating with some other scientists in producing some thousand chemical versions of logic gates that is going to become a form of chemical pocket calculator. One of the problems with the present version of this technology is the speed of the waves; they only spread at a rate of a few millimeters per minute. According to Adamatzky, this problem can be eliminated by placing the gates very close to each other, to make sure the signals are transferred quickly. Another possibility could be new chemical reactions where waves propagate much faster. If these teething problems are overcome, a chemical computer will offer clear advantages over an electronic computer.
An increasing number of individuals in the computer industry are starting to realize the potential of this technology. IBM is at the moment testing out new ideas in the field of microprocessing with many similarities to the basic principles of a chemical computer.
