Three-dimensional (3D) microwave cavities have been extensively used for coupling and interacting with superconducting quantum bits (qubits), providing a versatile platform for quantum control experiments and for realizing hybrid quantum systems. While having high quality factors (>106) superconducting cavities do not permit magnetic field control of qubits. In contrast, cavities made of normal metals are transparent to magnetic fields, but experience lower quality factors (∼104). We have created a hybrid cavity which is primarily composed of aluminium but also contains a small copper insert reaching the internal quality factor of ≃105, an order of magnitude improvement over all previously tested normal metal cavities. In order to demonstrate precise magnetic control, we performed spectroscopy of three superconducting qubits, where individual control of each qubit’s frequency was exerted with small external wire coils. An improvement in quality factor and magnetic field control makes this 3D hybrid cavity an attractive new element for circuit quantum electrodynamics experiments.

中文翻译：

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具有磁通量控制和增强品质因数的3D微波腔

三维（3D）微波腔已被广泛用于与超导量子位（qubit）耦合和相互作用，为量子控制实验和实现混合量子系统提供了一个通用平台。尽管具有高品质因数（> 106），但超导腔不允许磁场控制量子位。相反，由普通金属制成的空腔对磁场是透明的，但是质量因数较低（〜104）。我们创建了一个混合腔，该腔主要由铝组成，但还包含一个小的铜插入物，其内部品质因数达到≃105，比以前测试的所有普通金属腔都提高了一个数量级。为了演示精确的磁控制，我们对三个超导量子位进行了光谱分析，在这种情况下，每个外部量子线圈的频率分别由小型外部线圈控制。质量因数和磁场控制方面的改进使该3D混合腔成为电路量子电动力学实验中有吸引力的新元素。