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Preserving coherence in quantum computation by pairing quantum bits

Lu-Ming Duan·Guang-Can Guo
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Abstract

A scheme is proposed for protecting quantum states from both independent decoherence and cooperative decoherence. The scheme operates by pairing each qubit (two-state quantum system) with an ancilla qubit and by encoding the states of the qubits into the corresponding coherence-preserving states of the qubit-pairs. In this scheme, the amplitude damping (loss of energy) is prevented as well as the phase damping (dephasing) by a strategy called the free-Hamiltonian-elimination We further extend the scheme to include quantum gate operations and show that loss and decoherence during the gate operations can also be prevented.

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Lu-Ming Duan, Guang-Can Guo. 1997-10-03. Preserving coherence in quantum computation by pairing quantum bits. https://doi.org/10.1103/physrevlett.79.1953

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