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arXiv 2004.03870quant-phcs.SYeess.SY
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腔介导双量子点量子比特相干反馈网络的动力学研究

On the dynamics of a quantum coherent feedback network of cavity-mediated double quantum dot qubits

Zhiyuan Dong, Wei Cui, Guofeng Zhang

摘要:

本文的目的是提出一个全面的研究相干反馈网络的主要组成部分包括两个远距离的双量子点(DQD)量子比特,这是直接耦合到一个腔。该主要部件最近已经在物理上实现(van Woerkom,{ \it et al.},Microwave photon-mediated interactions between semiconductor qubits,Physical Review X,8(4):041018,2018)。反馈回路通过将该主要组件与分束器级联而闭合。从三个角度研究了这个相干反馈网络的动力学。首先,导出了由单光子态驱动的网络的输出单光子态的解析形式,特别地,观察到相干反馈大大延长了输入单光子与网络之间的相互作用.第二,当网络由单光子输入态驱动时,计算了DQD量子比特的激发概率。此外,当输入为真空,两个DQD量子比特中的一个初始化为激发态时,导出了网络态的显式表达式,特别是当两个DQD量子比特的跃迁频率相等时,输出场和两个DQD量子比特可以形成纠缠态.最后,得到了单光子输入在任意可控时刻都能完全激发两个DQD量子比特之一的脉冲形状的精确形式,这对构造$2$ -量子比特量子门有一定的参考价值.

英文摘要:

The purpose of this paper is to present a comprehensive study of a coherent feedback network where the main component consists of two distant double quantum dot (DQD) qubits which are directly coupled to a cavity. This main component has recently been physically realized (van Woerkom, {\it et al.}, Microwave photon-mediated interactions between semiconductor qubits, Physical Review X, 8(4):041018, 2018). The feedback loop is closed by cascading this main component with a beamsplitter. The dynamics of this coherent feedback network is studied from three perspectives. First, an analytic form of the output single-photon state of the network driven by a single-photon state is derived; in particular, it is observed that coherent feedback elongates considerably the interaction between the input single photon and the network. Second, excitation probabilities of DQD qubits are computed when the network is driven by a single-photon input state. Moreover, if the input is vacuum but one of the two DQD qubits is initialized in its excited state, the explicit expression of the state of the network is derived, in particular, it is shown that the output field and the two DQD qubits can form an entangled state if the transition frequencies of two DQD qubits are equal. Finally, the exact form of the pulse shape is obtained by which the single-photon input can fully excite one of these two DQD qubits at any controllable time, which may be useful in the construction of $2$-qubit quantum gates.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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