Note to users. If you're seeing this message, it means that your browser cannot find this page's style/presentation instructions -- or possibly that you are using a browser that does not support current Web standards. Find out more about why this message is appearing, and what you can do to make your experience of our site the best it can be.

Science 19 December 2003:
Vol. 302. no. 5653, pp. 2098 - 2100
DOI: 10.1126/science.1090790
Prev | Table of Contents | Next

Reports

Pseudo-Random Unitary Operators for Quantum Information Processing

Joseph Emerson,1*{dagger}{ddagger} Yaakov S. Weinstein,1* Marcos Saraceno,3 Seth Lloyd,2 David G. Cory1

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.

1 Department of Nuclear Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
2 Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
3 Unidad de Actividad Fisica, Tandar, Comisión Nacional de Energía Atómica, 1429, Buenos Aires, Argentina.



* These authors contributed equally to this work.

{dagger} Present address: Perimeter Institute for Theoretical Physics, 35 King Street N., Waterloo, Ontario N2J 2W9, Canada.

{ddagger} To whom correspondence should be addressed. E-mail: jemerson{at}perimeterinstitute.ca

Read the Full Text


THIS ARTICLE HAS BEEN CITED BY OTHER ARTICLES:
Symmetrized Characterization of Noisy Quantum Processes.
J. Emerson, M. Silva, O. Moussa, C. Ryan, M. Laforest, J. Baugh, D. G. Cory, and R. Laflamme (2007)
Science 317, 1893-1896
   Abstract »    Full Text »    PDF »


To Advertise     Find Products

Science. ISSN 0036-8075 (print), 1095-9203 (online)