统一纵向与色散读出的Floquet理论
Unifying Floquet theory of longitudinal and dispersive readout
AI总结：
本文提出统一纵向与色散读出的Floquet理论，揭示交流斯塔克位移斜率与曲率分别控制纵向耦合和色散位移，并在弱驱动下建立联系，适用于超导与自旋混合电路QED系统。
摘要：
我们针对电路量子电动力学（circuit QED）中的纵向读出与色散读出，构建了一套Floquet理论。通过研究以腔共振频率ω_r驱动的、与腔光子耦合的量子比特，我们建立了量子比特交流斯塔克位移与光子纵向耦合及色散耦合之间的普适联系。我们发现，纵向耦合g_∥由交流斯塔克位移随驱动强度A_q变化的斜率所控制，而色散位移χ则取决于其曲率。在弱驱动极限（A_q→0）下，这两个量彼此成正比。我们的方法统一了绝热极限（ω_r→0）——其中g_∥由静态谱曲率（或量子电容）产生——与含时（diabatic）极限，在后者中静态谱不起作用。我们推导了解析结果，并通过精确数值模拟加以验证。我们将这些结果应用于超导与自旋混合cQED系统，展示了比色散读出更快的纵向读出的灵活性。
英文摘要：
We devise a Floquet theory of longitudinal and dispersive readout in circuit QED. By studying qubits coupled to cavity photons and driven at the resonance frequency of the cavity $ω_{\rm r}$, we establish a universal connection between the qubit AC Stark shift and the longitudinal and dispersive coupling to photons. We find that the longitudinal coupling $g_\parallel$ is controlled by the slope of the AC Stark shift as function of the driving strength $A_{\rm q}$, while the dispersive shift $χ$ depends on its curvature. The two quantities become proportional to each other in the weak drive limit ($A_{\rm q}\rightarrow 0$). Our approach unifies the adiabatic limit ($ω_{\rm r}\rightarrow 0$) -- where $g_\parallel$ is generated by the static spectrum curvature (or quantum capacitance) -- with the diabatic one, where the static spectrum plays no role. We derive analytical results supported by exact numerical simulations. We apply them to superconducting and spin-hybrid cQED systems, showcasing the flexibility of faster-than-dispersive longitudinal readout.
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。
