arXiv subjects

Andre Wobst

Publications and source records attributed to Andre Wobst.

4 recordsLinked to original sources

arXiv2003

Phase space signatures of the Anderson transition

We use the inverse participation ratio based on the Husimi function to perform a phase space analysis of the Anderson model in one, two, and three dimensions. Important features of the quantum states remain observable in phase space in the large system size limit, while they would be lost in a real or momentum space description. From perturbative approaches in the limits of weak and strong disorder, we find that the appearance of a delocalization-localization transition is connected to the coupling, by a weak potential, of momentum eigenstates which are far apart in momentum space. This is consistent with recent results obtained for the Aubry-Andre model and provides a novel view on the metal-insulator transition.

cond-mat.dis-nn↗

arXiv2002

Delocalization and Heisenberg's uncertainty relation

In the one-dimensional Anderson model the eigenstates are localized for arbitrarily small amounts of disorder. In contrast, the Harper model with its quasiperiodic potential shows a transition from extended to localized states. The difference between the two models becomes particularly apparent in phase space where Heisenberg's uncertainty relation imposes a finite resolution. Our analysis points to the relevance of the coupling between momentum eigenstates at weak potential strength for the delocalization of a quantum particle.

cond-mat.dis-nn↗

arXiv2001

From ballistic motion to localization: a phase space analysis

We introduce phase space concepts to describe quantum states in a disordered system. The merits of an inverse participation ratio defined on the basis of the Husimi function are demonstrated by a numerical study of the Anderson model in one, two, and three dimensions. Contrary to the inverse participation ratios in real and momentum space, the corresponding phase space quantity allows for a distinction between the ballistic, diffusive, and localized regimes on a unique footing and provides valuable insight into the structure of the eigenstates.

cond-mat.dis-nn↗

arXiv1998

Two interacting particles in a disordered chain IV: Scaling of level curvatures

The curvatures of two-particle energy levels with respect to the enclosed magnetic flux in mesoscopic disordered rings are investigated numerically. We find that the typical value of the curvatures is increased by interactions in the localised regime and decreased in the metallic regime. This confirms a prediction by Akkermans and Pichard (Eur. Phys. J. B 1, 223 (1998)). The interaction-induced changes of the typical curvatures at different energies and disorder strengths exhibit one-parameter scaling with a conductance-like single parameter. This suggests that interactions could influence the conductance of mesoscopic systems similarly.

cond-mat.dis-nn↗