Département de Physique Théorique, Université de Genève, 1211 Genève, Switzerland.
Phys Rev Lett. 2012 May 4;108(18):186806. doi: 10.1103/PhysRevLett.108.186806. Epub 2012 May 3.
Electron transport in mesoscopic conductors has traditionally involved investigations of the mean current and the fluctuations of the current. A complementary view on charge transport is provided by the distribution of waiting times between charge carriers, but a proper theoretical framework for coherent electronic systems has so far been lacking. Here we develop a quantum theory of electron waiting times in mesoscopic conductors expressed by a compact determinant formula. We illustrate our methodology by calculating the waiting time distribution for a quantum point contact and find a crossover from Wigner-Dyson statistics at full transmission to Poisson statistics close to pinch-off. Even when the low-frequency transport is noiseless, the electrons are not equally spaced in time due to their inherent wave nature. We discuss the implications for renewal theory in mesoscopic systems and point out several analogies with level spacing statistics and random matrix theory.
介观导体中的电子输运传统上涉及对平均电流和电流涨落的研究。载流子之间的等待时间分布为电荷输运提供了一个互补的观点，但到目前为止，对于相干电子系统还缺乏一个合适的理论框架。在这里，我们通过紧凑的行列式公式发展了介观导体中电子等待时间的量子理论。我们通过计算量子点接触的等待时间分布来说明我们的方法，并发现从完全传输的维格纳-迪森统计到接近截止的泊松统计的交叉。即使在低频传输没有噪声的情况下，由于电子固有的波动性，它们在时间上也不是等距的。我们讨论了这对介观系统中更新理论的影响，并指出了与能级间距统计和随机矩阵理论的几个类似之处。
