论文标题
电路量子电动力学的饱和purcell滤波器
Saturable Purcell filter for circuit quantum electrodynamics
论文作者
论文摘要
我们考虑了典型的QED设置，其中人造原子编码一个量子，并分散与测量谐振器耦合，该谐振器又耦合到传输线。从理论上讲，通过将另一个人工原子放置在该传输线中以充当过滤器，将量子的purcell腐烂到传输线中。当在传输线中应用强控制场时，过滤器将饱和并有效地关闭。这样的percell滤波能力允许使用单个传输线对量子的控制和测量，同时在没有控制脉冲的情况下保持量子的较长连贯时间。我们表明，可以使用简单的脉冲形状来实现量子上的高保真pauli $σ_x$门。对于已经使用一条传输线进行控制和测量量子的设备，我们的工作提供了一种完全过滤量子频率的方法，而无需删除控制系统的可能性。此外，将提出的过滤器与频率多路复用相结合，可以使用单个Purcell滤波器传输线对几个Qubits进行控制和测量。这将通过减少所需传输线的数量来增强超导量子处理器的可扩展性。
We consider a typical circuit QED setup where an artificial atom encodes a qubit and is dispersively coupled to a measurement resonator that in turn is coupled to a transmission line. We show theoretically that by placing another artificial atom in this transmission line to act as a filter, the Purcell decay of the qubit into the transmission line is suppressed. When strong control fields are applied in the transmission line, the filter is saturated and effectively switched off. Such a Purcell filtering capability permits both the control and measurement of the qubit using the single transmission line, while maintaining the long coherence time of the qubit in the absence of the control pulses. We show that high fidelity Pauli $σ_x$ gates on the qubit can be realized using simple pulse shapes. For devices that already use one transmission line both for control and measurement of the qubit, our work provides a way to completely filter out the qubit frequency without removing the possibility of controlling the system. Further, combining the proposed filter with frequency multiplexing potentially enables both control and measurement of several qubits using a single Purcell-filtered transmission line. This will enhance the scalability of superconducting quantum processors by decreasing the number of the required transmission lines.
