Langer C, Ozeri R, Jost J D, Chiaverini J, Demarco B, Ben-Kish A, Blakestad R B, Britton J, Hume D B, Itano W M, Leibfried D, Reichle R, Rosenband T, Schaetz T, Schmidt P O, Wineland D J
National Institute of Standards and Technology, 325 Broadway, Boulder, Colorado 80305, USA.
Phys Rev Lett. 2005 Aug 5;95(6):060502. doi: 10.1103/PhysRevLett.95.060502. Epub 2005 Aug 2.
We demonstrate experimentally a robust quantum memory using a magnetic-field-independent hyperfine transition in 9Be+ atomic ion qubits at a magnetic field B approximately = 0.01194 T. We observe that the single physical qubit memory coherence time is greater than 10 s, an improvement of approximately 5 orders of magnitude from previous experiments with 9Be+. We also observe long coherence times of decoherence-free subspace logical qubits comprising two entangled physical qubits and discuss the merits of each type of qubit.
我们通过在约(B = 0.01194)T的磁场中利用(^{9}Be^{+})原子离子量子比特中与磁场无关的超精细跃迁，通过实验展示了一种稳健的量子存储器。我们观察到单个物理量子比特的存储相干时间大于(10)秒，相较于之前对(^{9}Be^{+})的实验，提高了约(5)个数量级。我们还观察到由两个纠缠物理量子比特组成的无退相干子空间逻辑量子比特的长相干时间，并讨论了每种类型量子比特的优点。
