The quantum search algorithm: http://en.wikipedia.org/wiki/Grovers_algorithm http://en.wikipedia.org/wiki/Grovers_algorithm It lets you search a completely un

The quantum search algorithm: http://en.wikipedia.org/wiki/Grovers_algorithm http://en.wikipedia.org/wiki/Grovers_algorithm It lets you search a completely unstructured N-item search space using the square root (!) of N queries, not the N queries you'd think were necessary. Also, the algorithm is so simple that once you know it's possible, and provided you're very comfortable with basic quantum mechanics, it's almost trivial to find the algorithm.