We study the transport properties of an Anderson-Holstein model with orbital degeneracies and a tunneling phase that allows for the formation of dark states. The resulting destructive interference yields a characteristic pattern of positive and negative differential conductance features with enhanced shot noise, without further asymmetry requirements in the coupling to the leads. The transport characteristics are strongly influenced by the Lamb-shift renormalization of the system Hamiltonian. Thus, the electron-vibron coupling cannot be extracted by a simple fit of the current steps to a Poisson distribution. For strong vibronic relaxation, a simpler effective model with analytical solution allows for a better understanding and moreover demonstrates the robustness of the described effects.

中文翻译：

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退化的Anderson-Holstein模型中的干扰和散粒噪声

我们研究具有轨道简并性和允许形成暗态的隧穿相的安德森-霍尔斯坦模型的传输性质。所产生的相消干涉产生具有增强散粒噪声的正和负差分电导特征的特征模式，而在与引线耦合时没有进一步的不对称要求。运输特性受到系统哈密顿量的Lamb-shift重归一化的强烈影响。因此，不能通过将电流阶跃简单地拟合为泊松分布来提取电子-电子耦合。对于强烈的振动松弛，带有解析解决方案的更简单有效的模型可以更好地理解，并且证明了所描述效果的鲁棒性。