Stabilizing Rabi Oscillation of a Charge Qubit via Atomic Clock Technique

摘要

We propose a superconducting circuit-atom hybrid, where the Rabi oscillationof single excess Cooper pair in the island is stabilized via the commonatomic-clock technique. The noise in the superconducting circuit is mapped ontothe voltage source which biases the Cooper-pair box via an inductor and a gatecapacitor. The fast fluctuations of the gate charge are significantlysuppressed by an inductor-capacitor resonator, leading to along-relaxation-time Rabi oscillation. More importantly, the residuallow-frequency fluctuations are further reduced by using the generalfeedback-control method, in which the voltage bias is stabilized viacontinuously measuring the dc-Stark-shift-induced atomic Ramsey signal. Thestability and coherence time of the resulting charge-qubit Rabi oscillation areboth enhanced. The principal structure of this Cooper-pair-box oscillator isstudied in detail.