PT - JOURNAL ARTICLE
AU - Emerson, Joseph
AU - Weinstein, Yaakov S.
AU - Saraceno, Marcos
AU - Lloyd, Seth
AU - Cory, David G.
TI - Pseudo-Random Unitary Operators for Quantum Information Processing
AID - 10.1126/science.1090790
DP - 2003 Dec 19
TA - Science
PG - 2098--2100
VI - 302
IP - 5653
4099 - http://science.sciencemag.org/content/302/5653/2098.short
4100 - http://science.sciencemag.org/content/302/5653/2098.full
SO - Science2003 Dec 19; 302
AB - In close analogy to the fundamental role of random numbers in classical information theory, random operators are a basic component of quantum information theory. Unfortunately, the implementation of random unitary operators on a quantum processor is exponentially hard. Here we introduce a method for generating pseudo-random unitary operators that can reproduce those statistical properties of random unitary operators most relevant to quantum information tasks. This method requires exponentially fewer resources, and hence enables the practical application of random unitary operators in quantum communication and information processing protocols. Using a nuclear magnetic resonance quantum processor, we were able to realize pseudorandom unitary operators that reproduce the expected random distribution of matrix elements.