We demonstrate the local control of up to eight two-level systems interacting strongly with a microwave cavity. Following calibration, the frequency of each individual two-level system (qubit) is tunable without influencing the others. Bringing the qubits one by one on resonance with the cavity, we observe the collective coupling strength of the qubit ensemble. The splitting scales up with the square root of the number of the qubits, which is the hallmark of the Tavis-Cummings model. The local control circuitry causes a bypass shunting the resonator, and a Fano interference in the microwave readout, whose contribution can be calibrated away to recover the pure cavity spectrum. The simulator’s attainable size of dressed states with up to five qubits is limited by reduced signal visibility, and -if uncalibrated- by off-resonance shifts of sub-components. Our work demonstrates control and readout of quantum coherent mesoscopic multi-qubit system of intermediate scale under conditions of noise.

中文翻译：

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用中规模超导电路探究Tavis-Cummings电平分裂

我们演示了多达八个与微波腔强烈相互作用的两级系统的局部控制。校准后，每个单独的两级系统（qubit）的频率是可调的，而不会影响其他系统。将量子位与谐振腔一一对应，我们观察到量子位集合体的集体耦合强度。拆分与qubit数的平方根成比例增加，这是Tavis-Cummings模型的标志。本地控制电路会引起谐振器的旁路分流，以及微波读数中的Fano干扰，可以校正其贡献以恢复纯腔谱。模拟器可达到的状态变化（最多5个量子位）的大小受到信号可见度降低的限制，如果未校准，则通过子组件的共振偏移进行。我们的工作演示了在噪声条件下中尺度量子相干介观多量子位系统的控制和读出。