Regensburg 2016 – wissenschaftliches Programm

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DY: Fachverband Dynamik und Statistische Physik

DY 26: Poster - Quanten Systems

DY 26.5: Poster

Dienstag, 8. März 2016, 18:15–21:00, Poster C

Distance dependence of fluctuations in mesoscopic transport: From branched flow to UCFs — •Kazuhiro Kubo and Martina Hentschel — Technische Universität Ilmenau, Institut für Physik, Ilmenau, Germany

We investigate the propagation of electrons starting from a quantum point contact-like source in a two dimensional random potential with spatial Gaussian correlation. We calculate the density of classical trajectories and find the well-known branching pattern near the source. However, we observe its gradual disappearance into a homogeneously fluctuating pattern at larger distances away from the source. This is accompanied by a continuous change in the trajectory-density probability distribution from lognormal-like to Gaussian-like, which is suggestive of change of the transport dynamics from ballistic to diffusive. We present the distribution of momenta, and confirm that, for shorter distances, a certain direction corresponding to the branched flow is properly preferred, while there is no such a direction at larger distances. Also, we show that the intensity distribution of each trajectory at a given distance can be obtained by correctly taking into account the distribution of travelling times to points at a certain distance from the source. These results are compared with those of the quasi one-dimensional (i.e. one of space coordinates is proportional to time) case to clarify the dependence on the degree of freedom.