# Mathematical Digest

### Short Summaries of Articles about Mathematics

in the Popular Press

"Knotty Calculations," by Erica Klarreich. *Science News,* 22 February 2003,pages 124-126.

The miniaturization of computer chips is leading to scales where quantummechanics principles predominate. This article discusses the connection betweenknot theory and quantum computing, specifically topological quantum computing.Information in topological quantum computing is encoded using braids, insteadof qubits. Not only has topological quantum computing been shown to be aseffective as quantum computing, but it has the advantage that its informationis less fragile than that of quantum computing (where each bit is encoded inthe state of a single particle). Most of the article is concerned withapplications to new computing, but Klarreich concludes with a quote fromMichael Freedman of Microsoft Research: "I'm working on this because themathematics is so beautiful,... It's an excuse to think about the two mostinteresting things in the world: topology and theoretical physics."

*--- Mike Breen*