Chemical Physics Theory Group, Department of Chemistry, and Centre for Quantum Information and Quantum Control, University of Toronto, 80 Saint George St., Toronto, Ontario M5S 3H6, Canada.
J Chem Phys. 2017 Aug 7;147(5):054104. doi: 10.1063/1.4996562.
We study the interacting, symmetrically coupled single impurity Anderson model. By employing the nonequilibrium Green's function formalism, we reach an exact relationship between the steady-state charge current flowing through the impurity (dot) and its occupation. We argue that the steady-state current-occupation relation can be used to assess the consistency of simulation techniques and identify spurious transport phenomena. We test this relation in two different model variants: First, we study the Anderson-Holstein model in the strong electron-vibration coupling limit using the polaronic quantum master equation method. We find that the current-occupation relation is violated numerically in standard calculations, with simulations bringing up incorrect transport effects. Using a numerical procedure, we resolve the problem efficiently. Second, we simulate the Anderson model with electron-electron interaction on the dot using a deterministic numerically exact time-evolution scheme. Here, we observe that the current-occupation relation is satisfied in the steady-state limit-even before results converge to the exact limit.
我们研究了相互作用、对称耦合的单个杂质安德森模型。通过采用非平衡格林函数形式，我们得到了通过杂质（点）流动的稳态电荷电流与其占据数之间的确切关系。我们认为，稳态电流-占据关系可用于评估模拟技术的一致性并识别虚假的输运现象。我们在两种不同的模型变体中测试了这一关系：首先，我们使用极化子量子主方程方法研究了在强电子-振动耦合极限下的安德森-霍尔斯滕模型。我们发现，在标准计算中数值上违反了电流-占据关系，模拟带来了不正确的输运效应。通过数值程序，我们有效地解决了这个问题。其次，我们使用确定性的数值精确时间演化方案在点上模拟了具有电子-电子相互作用的安德森模型。在这里，我们观察到，即使在结果收敛到精确极限之前，在稳态极限下电流-占据关系也得到满足。
