Joint quantum state tomography of an entangled qubit–resonator hybrid
Joint quantum state tomography of an entangled qubit–resonator hybrid
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DOI：
10.1088/1367-2630/15/12/125027
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发表时间：
2013-12
影响因子：
3.3
通讯作者：
X. Linpeng;H Z Zhang;K. Xu;C. Y. Li;Y. Zhong;Z. L. Wang;H. Wang;Q. Xie
中科院分区：
文献类型：
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作者：
X. Linpeng;H Z Zhang;K. Xu;C. Y. Li;Y. Zhong;Z. L. Wang;H. Wang;Q. Xie
将超导量子比特和谐振器集成在一个电路中，为量子信息处理（QIP）提供了一个很有前途的解决方案，这也实现了腔量子电动力学（QED）的片上模拟，称为电路QED。在大多数原型电路设计中，量子位是有源处理元件，谐振器是外围设备。由于共振器通常具有更好的相干性能和更容易达到的能级，因此提出纠缠量子比特-共振器混合体可以用作处理元件。为了实现这一目标，首先需要对混合体进行精确测量。在这里，我们展示了一个联合量子态层析成像（QST）技术，充分表征纠缠量子比特谐振器混合。我们通过生成和准确表征多个状态，例如，|gN +|（1）（1）（2）（|格兰德|（1）是一个量子比特的基态和激发态，|0分，...，|N是共振器的Fock态。我们进一步提供了一个数值方法来提高QST效率和测量的退相干动力学的二分混合，见证来自量子比特和N-光子Fock态的耗散。因此，联合QST是积极使用量子位谐振器元件用于混合量子器件中的QIP和研究电路QED的重要一步。
The integration of superconducting qubits and resonators in one circuit offers a promising solution for quantum information processing (QIP), which also realizes the on-chip analogue of cavity quantum electrodynamics (QED), known as circuit QED. In most prototype circuit designs, qubits are active processing elements and resonators are peripherals. As resonators typically have better coherence performance and more accessible energy levels, it is proposed that the entangled qubit–resonator hybrid can be used as a processing element. To achieve such a goal, an accurate measurement of the hybrid is first necessary. Here we demonstrate a joint quantum state tomography (QST) technique to fully characterize an entangled qubit–resonator hybrid. We benchmarked our QST technique by generating and accurately characterizing multiple states, e.g. |gN〉 + |e(N − 1)〉 where (|g〉 and |e〉) are the ground and excited states of the qubit and (|0〉,…,|N〉) are Fock states of the resonator. We further provided a numerical method to improve the QST efficiency and measured the decoherence dynamics of the bipartite hybrid, witnessing dissipation coming from both the qubit and the N-photon Fock state. As such, the joint QST presents an important step toward actively using the qubit–resonator element for QIP in hybrid quantum devices and for studying circuit QED.