Multi-photon behaviors of shot noise in a quantum dot system under the perturbation of two microwave fields
Multi-photon behaviors of shot noise in a quantum dot system under the perturbation of two microwave fields
复制标题
两个微波场扰动下量子点系统散粒噪声的多光子行为
DOI：
10.1140/epjb/e2007-00300-7
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发表时间：
2007
期刊：
影响因子：
--
通讯作者：
Jian Wang
中科院分区：
文献类型：
--
作者：
Hong;Jian Wang
我们研究了频率为ω1和ω2的两个微波场(MWF)的微扰对散粒噪声的影响，这两个微波场可以分为公度和非公度的外部交流电场。得到了随时间变化的电流关联函数和散粒噪声的谱密度。在交流电势的非线性区域，它们与单场作用系统有很大的不同。不同的光子吸收和发射过程会产生不同的噪声谱密度。我们对相称的平衡和非平衡的光子吸收和发射进行了数值计算。从散粒噪声的共振可以清楚地看到多光子过程。不同的公度数Q=ω2/ω1有助于不同的光子吸收和发射行为。结果表明，散粒噪声的非对称位形与公度数Q密切相关，微分电导表现为对称和非对称行为，通道阻塞现象明显。在非平衡光子吸收的情况下，散粒噪声大到足以超过其饱和值。Fano因子对不同的交流场公度数和幅值的敏感行为表明，外加MWFS可以显着地控制散粒噪声。
We have investigated the shot noise affected by the perturbation of two microwave fields (MWFs) with frequencies ω1and ω2, which can be classified as the commensurate and incommensurate external ac fields. The time-dependent current correlation function and the spectral density of shot noise have been obtained. They are very different compared with the single-field applied system in the nonlinear regime of the ac potentials. The different photon absorption and emission processes induce different kinds of noise spectral density. We have performed the numerical calculations for both commensurate balanced and unbalanced photon absorptions and emissions. The multi-photon procedure can be seen clearly from the resonance of shot noise. Different commensurate number q = ω2/ω1contributes to different photon absorption and emission behaviors. It is found that the asymmetric configuration of shot noise is intimately associated with the commensurate number q. The differential conductance appears symmetric and asymmetric behaviors, and the channel blockade exhibits. The shot noise is large enough to surpass its saturated value for the unbalanced photon absorption case. The sensitive behaviors of Fano factor associated with different commensurate numbers and amplitudes of ac fields signify that the shot noise can be controlled by external MWFs significantly.