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arXiv 1012.2916quant-ph
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耗散环境中受驱动人工原子的最佳冷却

Optimal cooling of a driven artificial atom in dissipative environment

Lingjie Du, Yang Yu

摘要:

研究了环境噪声作用下超导磁通量子比特的微波冷却。对于弱的退相干,我们的分析结果与实验观察到的简并点附近的最佳冷却的微波振幅应线性依赖于直流磁通失谐。随着退相干的增加,更多的振动自由度耦合进来,使得普通的冷却方法效率降低甚至失效。我们提出了一种改进的冷却方法,它可以消除额外的振动自由度的扰动,从而保持高效率,即使在强退相干。此外,我们还指出,在两种方法中,退相干都将调制微波驱动的Landau-Zener跃迁达到最大值的频率,显示出非相干动力学的特征,这对于量子比特和其他量子系统的最佳冷却是非常重要的。

英文摘要:

We study microwave-driven cooling in a superconducting flux qubit subjected to environment noises. For the weak decoherence, our analytical results agree well with the experimental observations near the degeneracy point and show that the microwave amplitude for optimal cooling should depend linearly on the dc flux detuning. With the decoherence increasing, more vibrational degrees of freedom couple in, making the ordinary cooling method less effective or even fail. We propose an improved cooling method, which can eliminate the perturbation of additional vibrational degrees of freedom hence keep high efficiency even under the strong decoherence. Furthermore, we point out that the decoherence will modulate the frequency where microwave-driven Landau-Zener transition reaches maximum in both methods, displaying the feature of incoherent dynamics which is important for the optimal cooling of qubits and other quantum systems.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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