In quantum information processing, it is vital to protect the coherence of qubits in noisy environments. Dynamical decoupling （DD）, which applies a sequence of flips on qubits and averages the qubit-environment coup...In quantum information processing, it is vital to protect the coherence of qubits in noisy environments. Dynamical decoupling （DD）, which applies a sequence of flips on qubits and averages the qubit-environment coupling to zero, is a promising strategy compatible with other desired functionalities, such as quantum gates. Here, we review the recent progresses in theories of dynamical decoupling and experimental demonstrations. We give both semiclassical and quantum descriptions of the qubit decoherence due to coupling to noisy environments. Based on the quantum picture, a geometrical interpretation of DD is presented. The periodic Carr Purcell-Meiboom-Gill DD and the concatenated DD are reviewed, followed by a detailed exploration of the recently developed Uhrig DD, which employs the least number of pulses in an unequally spaced sequence to suppress the qubit-environment coupling to a given order of the evolution time. Some new developments and perspectives are also discussed.展开更多
基金Acknowledgements The work was supported by Hong Kong RGC/GRF CUHK402209. W. Yang would like to acknowledge the support by Natural Science Foundation （PHY 0804114） and ARO/IA RPA （W911NF-08-1-0487）. We are grateful to D. Lidar for critical reading and useful comments.
文摘In quantum information processing, it is vital to protect the coherence of qubits in noisy environments. Dynamical decoupling （DD）, which applies a sequence of flips on qubits and averages the qubit-environment coupling to zero, is a promising strategy compatible with other desired functionalities, such as quantum gates. Here, we review the recent progresses in theories of dynamical decoupling and experimental demonstrations. We give both semiclassical and quantum descriptions of the qubit decoherence due to coupling to noisy environments. Based on the quantum picture, a geometrical interpretation of DD is presented. The periodic Carr Purcell-Meiboom-Gill DD and the concatenated DD are reviewed, followed by a detailed exploration of the recently developed Uhrig DD, which employs the least number of pulses in an unequally spaced sequence to suppress the qubit-environment coupling to a given order of the evolution time. Some new developments and perspectives are also discussed.
