Coherent quantum state storage and transfer between two phase qubits via a resonant cavity
Coherent quantum state storage and transfer between two phase qubits via a resonant cavity
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DOI：
10.1038/nature06124
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发表时间：
2007-09-27
期刊：
影响因子：
64.8
通讯作者：
Simmonds, Raymond W.
中科院分区：
文献类型：
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作者：
Sillanpaeae, Mika A.;Park, Jae I.;Simmonds, Raymond W.
与经典信息处理一样，量子信息处理器需要可以独立寻址和读出的比特(量子比特)，存储任意量子态(1，2)的长期存储元件，以及通过大量量子比特(3，4)可访问的相干通信总线传输量子信息的能力。用可伸缩微制造技术制造的超导量子比特是实现大规模量子信息处理器(5-9)的一个很有前途的候选者。虽然这些系统已经成功地通过了多达四个量子比特(10-13)的相干耦合测试，但超导量子比特之间通过量子总线进行单个量子态的通信还没有实现。在这里，我们进行了一个实验，演示了通过量子总线在两个超导约瑟夫森相位量子比特之间相干传输量子态的能力。这种量子母线是由一条长度为7毫米的开放式超导传输线形成的谐振腔。在用第一个量子比特准备了初始量子态之后，这个量子信息被传输和存储为谐振腔的非经典光子态，然后通过连接到腔的另一端的第二个量子比特来检索。除了简单的状态转移，这些结果表明高品质因数超导腔也可以作为有用的短期记忆元件。这里提出的基本结构可以扩展，为大量超导量子比特的相干相互作用提供了可能性。
As with classical information processing, a quantum information processor requires bits (qubits) that can be independently addressed and read out, long-term memory elements to store arbitrary quantum states(1,2), and the ability to transfer quantum information through a coherent communication bus accessible to a large number of qubits(3,4). Superconducting qubits made with scalable microfabrication techniques are a promising candidate for the realization of a large-scale quantum information processor(5-9). Although these systems have successfully passed tests of coherent coupling for up to four qubits(10-13), communication of individual quantum states between superconducting qubits via a quantum bus has not yet been realized. Here, we perform an experiment demonstrating the ability to coherently transfer quantum states between two superconducting Josephson phase qubits through a quantum bus. This quantum bus is a resonant cavity formed by an open-ended superconducting transmission line of length 7 mm. After preparing an initial quantum state with the first qubit, this quantum information is transferred and stored as a nonclassical photon state of the resonant cavity, then retrieved later by the second qubit connected to the opposite end of the cavity. Beyond simple state transfer, these results suggest that a high-quality-factor superconducting cavity could also function as a useful short-term memory element. The basic architecture presented here can be expanded, offering the possibility for the coherent interaction of a large number of superconducting qubits.