Friday, April 02, 2004

Combatting Decoherence, Plus Low Overhead Error Correction

The Economist.com has a story on Quantum computing. The first half is the standard intro, but some interesting new results are mentioned in the second half of the story:

*"Chikako Uchiyama of Yamanashi University, in Japan, discussed how, in the general case, the application of very short pulses, poetically known as bang-bang pulses, at regular intervals can serve not only to suppress decoherence, but also to maintain entanglementâ€”the quantum coupling between several qubits which allows computations to get done."*

Also:

*"Kaveh Khodjasteh of the University of Toronto looked at a related question, focusing on decoherence rather than disentanglement. He showed how a quantum error-correcting code which introduced only one extra qubit for error correction would create a robust system for quantum computation which had tolerance for faults caused by spontaneous emission, another bizarre quantum effect."*