Analysis of universality in transient dynamics of coherent electronic transport
Rubén Seoane Souto, Álvaro Martín-Rodero, Alfredo Levy Yeyati
备注：
8 pages, 6 figures, invited contribution to special volume "FQMT'15: Frontiers of Quantum and Mesoscopic Thermodynamics (Prague, Czech Republic, 27 July - 1 August 2015)"
We analyze the time-dependent full-counting statistics of charges transmitted through a quantum dot in the coherent regime. The generating function for the time-dependent charge transfer statistics is evaluated numerically by discretizing the Keldysh time contour, which allows us to compute the higher order charge and current cumulants. We also develop an analytic expression for all order cumulants at any time given as a function of the zeros of the generating function, finding that the short time universality is due to the presence of a dominant single zero. The robustness of the universal features at short times is studied in both the sequential and coherent regimes.
Nonlinear Optical Observation of Coherent Acoustic Dirac Plasmons in Thin-Film Topological Insulators
具有类声线性色散的低能电子集体激发在实验和理论上都得到了广泛的研究。然而，在时域测量中出现的相干声等离子体模式很少观察到由于单粒子连续朗道阻尼。在这里，我们报告的观察相干声学狄拉克等离子体（CADP）模式激发间接（静电）对表面耦合薄膜的拓扑绝缘体Bi 2 Se 3。使用瞬态二次谐波发生，一种能够独立监测膜中的面内和面外电子动力学的技术，观察到GHz范围的振荡，而没有相应的瞬态反射率振荡。这些振荡被分配到由倏逝引导兰姆声波引起的横向磁和横向电引导CADP模式，并且由于相对表面狄拉克状态之间的费米子隧穿而保持朗道无阻尼。
