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arXiv 1606.04736cond-mat.mes-hallquant-ph
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单电子自旋与微波谐振器的耦合:控制横向和纵向耦合

Coupling a single electron spin to a microwave resonator: Controlling transverse and longitudinal couplings

Félix Beaudoin, Dany Lachance-Quirion, W. A. Coish, Michel Pioro-Ladrière

摘要:

微波频率超导谐振器非常适合执行色散量子比特读出,调解两个量子比特门,并在遥远的量子系统之间穿梭状态。这些应用的先决条件是强量子位-谐振器耦合。电子自旋量子比特和微波谐振器之间的强耦合可以通过关联自旋和轨道自由度来实现。这种关联可以通过双量子点中的单个电子与附近纳米磁体产生的空间不均匀磁场的塞曼耦合来实现。在本文中,我们考虑这样的设备和估计自旋共振器耦合的顺序~ 1 MHz的现实参数。此外,通过现实的模拟,我们表明,相对于纳米磁体的双点的精确位置允许在纯纵向耦合(与裸自旋哈密顿量交换)和纯横向(自旋非守恒)耦合之间进行选择。此外,我们建议的方法,以减轻在此耦合方案中引入的失相和弛豫通道。这一分析为实现微波谐振腔与GaAs双量子点中自旋单电子之间的相干态转移提供了一条清晰的途径,其保真度可达90%以上。改进的动态去耦序列、低噪声环境和更长寿命的微波腔模式可能会在不久的将来导致更高的结晶度。

英文摘要:

Microwave-frequency superconducting resonators are ideally suited to perform dispersive qubit readout, to mediate two-qubit gates, and to shuttle states between distant quantum systems. A prerequisite for these applications is a strong qubit-resonator coupling. Strong coupling between an electron-spin qubit and a microwave resonator can be achieved by correlating spin- and orbital degrees of freedom. This correlation can be achieved through the Zeeman coupling of a single electron in a double quantum dot to a spatially inhomogeneous magnetic field generated by a nearby nanomagnet. In this paper, we consider such a device and estimate spin-resonator couplings of order ~ 1 MHz with realistic parameters. Further, through realistic simulations, we show that precise placement of the double dot relative to the nanomagnet allows to select between a purely longitudinal coupling (commuting with the bare spin Hamiltonian) and a purely transverse (spin non-conserving) coupling. Additionally, we suggest methods to mitigate dephasing and relaxation channels that are introduced in this coupling scheme. This analysis gives a clear route toward the realization of coherent state transfer between a microwave resonator and a single electron spin in a GaAs double quantum dot with a fidelity above 90%. Improved dynamical decoupling sequences, low-noise environments, and longer-lived microwave cavity modes may lead to substantially higher fidelities in the near future.

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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