Mathematical Digest
Short Summaries of Articles about Mathematics in the Popular Press "Randomness in Quantum Computation," by Juan Pablo Paz. Science, 19 December 2003,pages 20762077. Randomness is useful in many computational settings, so a natural question ishow randomness could be achieved in quantum computation. Paz summarizesresearch done by Joseph Emerson and others that is published in the article"PseudoRandom Unitary Operators for Quantum Information Processing," beginningon page 2098 in the same issue. Although the "weirdness" of quantum theorycould suggest that randomness is easier to obtain in a quantum setting than itis in a traditional one, achieving randomness in quantum computation hasactually been shown to be exponentially hard. In the research article, Emersonand colleagues present a simple method for achieving nearrandomness. They showthat their method converges very quickly to true randomness.  Mike Breen
