|MadSci Network: Computer Science|
It may not be a bad idea to start by thinking about the limitations of conventional computers. Conventional computers are based on semiconductors. They are electronic and computing programs are stored. No matter how hard people try to produce more powerful microchips, there is a limitation simply because of physical laws. Simply speaking, among the advantages of quantum computing that people believe quantum computers could have over the conventional computers is the phenomenon of quantum parallelism. As will be discussed in some detail in the links below, computing can be done in parallel with a quantum computer and an algorithm making use of a quantum computer's parallelism. For example, an algorithm has been developed by Peter Shor of AT&T Bell laboratories to tackle the problem of factoring large numbers into their prime factors. This problem has been considered to be part of a class of problems defined as " HARD " and is in the heart of the mostly commonly used encryption schemes. Shor's algorithm takes advantage of quantum parallelism to give the results of the prime factorisation problem in a matter of seconds whereas a conventional computer would take, in some cases, more than the age of the universe to produce a result! There are some very good articles about quantum computers in fairly plain English. Here are some of them. 1. Quantum Computing with Molecules by N. Gershenfeld and I.L. Chuang http://www.sciam.com/1998/0698issue/0698gershenfeld.html 2. When Silicon Hits Its Limits, What's Next? http://www.byte.com/art/9604/sec7/art1.htm ..
Try the links in the MadSci Library for more information on Computer Science.