We experimentally performed complete and optimized quantum process tomography of quantum gates implemented on superconducting qubit-based IBM QX2 quantum processor via two constrained convex optimization (CCO) techniques: least squares optimization and compressed sensing optimization. We studied the performance of these methods by comparing the experimental complexity involved and the experimental fidelities obtained. We experimentally characterized several two-qubit quantum gates: identity gate, a controlled-NOT gate, and a SWAP gate. The general quantum circuit is efficient in the sense that the data needed to perform CCO-based process tomography can be directly acquired by measuring only a single qubit. The quantum circuit can be extended to higher dimensions and is also valid for other experimental platforms.

中文翻译：

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基于 IBM 量子体验的优化量子过程断层扫描的实验演示

我们通过两种约束凸优化 (CCO) 技术对在基于超导量子比特的 IBM QX2 量子处理器上实现的量子门进行了完整和优化的量子过程断层扫描：最小二乘优化和压缩传感优化。我们通过比较所涉及的实验复杂性和获得的实验保真度来研究这些方法的性能。我们通过实验表征了几个双量子比特的量子门：身份门、受控非门和 SWAP 门。通用量子电路是有效的，因为可以通过仅测量单个量子位直接获取执行基于 CCO 的过程断层扫描所需的数据。量子电路可以扩展到更高的维度，也适用于其他实验平台。