arXiv 1602.050902016-02quant-phcond-mat.mes-hall

QED腔中稳健量子态转移和量子比特读出的哈密顿工程

Hamiltonian engineering for robust quantum state transfer and qubit readout in cavity QED

Félix Beaudoin, Alexandre Blais, W. A. Coish

备注：: 26 pages, 5 figures
发表信息：: New J. Phys. 19, 023041 (2017)
DOI：: 10.1088/1367-2630/aa5d33

摘要：

量子态到存储器的传输、通过量子总线的长距离状态穿梭以及高保真读出是量子技术的重要任务。实现这些任务是具有挑战性的现实耦合到环境的存在。在这里，我们介绍和评估协议，可用于腔QED执行高保真量子态传输和快速量子非破坏量子比特读出通过哈密顿工程。我们发现，即使在由于非均匀加宽而导致的强退相的极限下，也可以在腔和单个量子比特之间进行高保真的状态转移。我们将这一结果推广到一个腔和一个逻辑量子比特之间的状态转移，该逻辑量子比特编码在一个大的$N$物理量子比特系综的集体模式中。根据去耦序列，我们表明，在合奏的不均匀性耦合两个集体明亮的状态，只有两个其他集体模式，剩下的$N-3$单激发态暗。此外，我们表明，大的信噪比和高的单次保真度可以实现在基于腔的量子位读出，即使在弱耦合限制。这些想法对于将单自旋耦合到微波腔的新系统可能是重要的。

英文摘要：

Quantum state transfer into a memory, state shuttling over long distances via a quantum bus, and high-fidelity readout are important tasks for quantum technology. Realizing these tasks is challenging in the presence of realistic couplings to an environment. Here, we introduce and assess protocols that can be used in cavity QED to perform high-fidelity quantum state transfer and fast quantum nondemolition qubit readout through Hamiltonian engineering. We show that high-fidelity state transfer between a cavity and a single qubit can be performed, even in the limit of strong dephasing due to inhomogeneous broadening. We generalize this result to state transfer between a cavity and a logical qubit encoded in a collective mode of a large ensemble of $N$ physical qubits. Under a decoupling sequence, we show that inhomogeneity in the ensemble couples two collective bright states to only two other collective modes, leaving the remaining $N-3$ single-excitation states dark. Moreover, we show that large signal-to-noise and high single-shot fidelity can be achieved in a cavity-based qubit readout, even in the weak-coupling limit. These ideas may be important for novel systems coupling single spins to a microwave cavity.

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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