Magnetic resonance realization of decoherence-free quantum computation

Phys Rev Lett. 2003 Nov 21;91(21):217904. doi: 10.1103/PhysRevLett.91.217904. Epub 2003 Nov 21.


We report the realization, using nuclear magnetic resonance techniques, of the first quantum computer that reliably executes a complete algorithm in the presence of strong decoherence. The computer is based on a quantum error avoidance code that protects against a class of multiple-qubit errors. The code stores two decoherence-free logical qubits in four noisy physical qubits. The computer successfully executes Grover's search algorithm in the presence of arbitrarily strong engineered decoherence. A control computer with no decoherence protection consistently fails under the same conditions.