We proposed a spectroscopic method that extends Ramsey's atomic spectroscopy to detect the transition frequency of a qubit fabricated on a superconducting circuit. The method uses a multi-interval train of qubit biases to implement an alternate resonant and dispersive couplings to an incident probe field. The consequent absorption spectrum of the qubit has a narrower linewidth at its transition frequency than that obtained from constantly biasing the qubit to resonance while the middle dispersive evolution incurs only a negligible shift in detected frequency. Modeling on transmon qubits, we find that the linewidth reduction reaches 23% and Ramsey fringes are simultaneously suppressed at extreme duration ratio of dispersion over resonance for a double-resonance scheme. If the scheme is augmented by an extra resonance segment, a further 37% reduction can be achieved.

中文翻译：

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具有弥散演化的超导量子位的拉姆齐光谱

我们提出了一种光谱学方法，该方法扩展了Ramsey原子光谱学，可检测在超导电路上制造的量子比特的跃迁频率。该方法使用多间隔的qubit偏置序列来实现与入射探测场的交替共振和色散耦合。量子比特的吸收光谱在其跃迁频率处的线宽比通过不断地将量子比特偏置到共振而中间的色散演化仅引起可忽略的频率偏移而得到的线宽更窄。对跨门量子比特进行建模，我们发现对于双共振方案，线宽减小达到23％，并且在色散与共振的极端持续时间比率下，同时抑制了Ramsey条纹。如果该方案增加了一个额外的共振段，