Based on the hierarchical equations of motion approach, we study the time-dependent transport properties of a strongly correlated quantum dot system in the Kondo regime (KR), mixed valence regime (MVR), and empty orbital regime (EOR). We find that the transient current in KR shows the strongest nonlinear response and the most distinct oscillation behaviors. Both behaviors become weaker in MVR and diminish in EOR. To understand the physical insight, we examine also the corresponding dot occupancies and the spectral functions, with their dependence on the Coulomb interaction, temperature, and applied step bias voltage. The above nonlinear and oscillation behaviors could be understood as the interplay between dynamical Kondo resonance and single electron resonant-tunneling.

中文翻译：

---

量子点的瞬态动力学：从近藤政权到混合价，再到空轨道政权

基于运动方法的层次方程，我们研究了在近藤（KR），混合价态（MVR）和空轨道态（EOR）中高度相关的量子点系统随时间的传输特性。我们发现，KR中的瞬态电流显示出最强的非线性响应和最明显的振荡行为。两种行为在MVR中变弱，而在EOR中则减弱。为了了解物理洞察力，我们还将检查相应的点占用率和光谱函数，以及它们对库仑相互作用，温度和施加的阶跃偏置电压的依赖性。上述非线性和振荡行为可以理解为动态近藤共振和单电子共振隧道之间的相互作用。