Demonstration of Controlled-Phase Gates between Two Error-Correctable Photonic Qubits
Demonstration of Controlled-Phase Gates between Two Error-Correctable Photonic Qubits
复制标题
两个可纠错光子量子位之间的控制相位门的演示
DOI：
10.1103/physrevlett.124.120501
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发表时间：
2020
影响因子：
8.6
通讯作者：
L. Sun
中科院分区：
文献类型：
--
作者：
Y. Xu;Y. Ma;W. Cai;X. Mu;W. Dai;W. Wang;L. Hu;X. Li;J. Han;H. Wang;Y. P. Song;Zhen-Biao Yang;Shi-Biao Zheng;L. Sun
为了实现容错量子计算，需要将量子信息存储在具有纠错功能的逻辑量子比特中，通过在多个物理量子比特之间分配逻辑状态或将其编码在高维系统的希尔伯特空间中来实现。这些可纠错的逻辑量子比特之间的量子门操作对于任何实际的量子计算任务的实现都是必不可少的，但还没有实验证明。在这里，我们展示了一种几何方法来实现控制相位门之间的两个逻辑量子比特编码的光子场存储在腔中。这些门是通过将辅助超导量子比特分散耦合到这些腔并驱动它根据腔的联合光子状态进行循环演化来实现的，这会产生条件几何相位。我们首先实现了光子量子比特的相位门，其逻辑基态编码在两个准正交相干态中，这对基于连续变量的量子计算具有重要意义。然后，我们使用这种几何方法来实现两个二进制编码的逻辑量子比特之间的控制相位门，这具有纠错功能。
To realize fault-tolerant quantum computing, it is necessary to store quantum information in logical qubits with error correction functions, realized by distributing a logical state among multiple physical qubits or by encoding it in the Hilbert space of a high-dimensional system. Quantum gate operations.between these error-correctable logical qubits, which are essential for implementation of any practical.quantum computational task, have not been experimentally demonstrated yet. Here we demonstrate a.geometric method for realizing controlled-phase gates between two logical qubits encoded in photonic fields stored in cavities. The gates are realized by dispersively coupling an ancillary superconducting qubit to these cavities and driving it to make a cyclic evolution depending on the joint photonic state of the.cavities, which produces a conditional geometric phase. We first realize phase gates for photonic qubits with the logical basis states encoded in two quasiorthogonal coherent states, which have important implications for continuous-variable-based quantum computation. Then we use this geometric method to implement a controlled-phase gate between two binomially encoded logical qubits, which have an error-correctable function.