报告题目：Single‐particle approach to mesoscopic transport
报告人：Prof. Shmuel Gurvitz（Weizmann Institute of Science, Israel）
时间：2014年6月20日 星期五 下午15:00—16:00
地点：物电学院报告厅

报 告 摘 要:
基于特定的单粒子基矢我们发展了一种新方法应用于介观系统的电子输运。尽管这种基矢会产生冗余的多粒子振幅，但是它能大大简化问题的处理。基于这种方法研究了无相互作用电子的输运，我们推广了瞬态流和含时势垒的朗道尔公式，其结果形式简单，且有清楚的物理解释。进一步，应用这种方法我们研究了通过振荡隧穿势垒的单量子点共振隧穿，我们获得了交流共振电流的解析表达式；然而，在绝热近似极限下，这个结果呈现了零偏压下的直流电流[电子抽运]。此外，这个方法也允许我们推导出任意偏压和温度下粒子数分辨的主方程，这个结果对于计数统计分析也是非常有用的。最后，我们演示了这个方法可应用于研究一个量子比特和单电子晶体管[一个探测装置]的相互作用，作为偏压和温度的函数，我们研究了量子比特的退相干[拉比振荡的衰减]。

We develop a new approach to electron transport in mesoscopic systems by using a particular single‐particle basis. Although this basis generates redundant many‐particle amplitudes, it greatly simplifies the treatment. By using our method for transport of non‐interacting electrons, we generalize the Landauer formula for transient currents and for time‐dependent potentials. The result has a very simple form and clear physical interpretation. As an example, we apply it to resonant tunneling through a quantum dot where the tunneling barriers are oscillating in time. We obtain analytical expression for the time‐dependent (ac) resonant current. However, in the adiabatic limit this expression displays the dc current for zero bias (electron pumping). The method allows us to derive the particle‐resolve master equations for any bias voltages and temperatures. The result would be very useful for the counting‐statistics analysis. We demonstrate that this approach can be applied for study of a qubit interacting with a single‐electron transistor (representing the measurement device). We investigate the qubit's decoherence (decay of the Rabi).