Critical behaviour of a disordered wave packet model

Antonio S. de Castro

R. P. A. Lima, F. A. B. F. de Moura, M. L. Lyra +1 more

We investigate the wave-packet dynamics of the power-law bond disordered one-dimensional Anderson model with hopping amplitudes decreasing as ${H}_{nm}\ensuremath{\propto}{\ensuremath{\mid}n\ensuremath{-}m\ensuremath{\mid}}^{\ensuremath{-}\ensuremath{\alpha}}$. We consider the critical case $(\ensuremath{\alpha}=1)$. Using an exact diagonalization scheme on finite chains, we compute the participation moments of all stationary energy eigenstates as well as the spreading of an initially localized wave packet. The eigenstates multifractality is characterized by the set of fractal dimensions of the participation moments. The wave packet shows a diffusivelike spread developing a power-law tail and achieves a stationary nonuniform profile after reflecting at the chain boundaries. As a consequence, the time-dependent participation moments exhibit two distinct scaling regimes. We formulate a finite-size scaling hypothesis for the participation moments relating their scaling exponents to the ones governing the return probability and wave-function power-law decays.

Uwe Krey

Uwe Krey

Kazumoto Ohnami, Kazuya Miyazaki, Y. Mikami

The interaction picture wave packet method is applied to hydrogen scattering with a model Gaussian potential barrier, the linear reaction model. Some new features for the behaviour of the interaction picture wave packet are pointed out. It also splits into two parts according to the separation of the original Schrödinger picture wave packet into transmitted and reflected parts. The interrelation between the two wave packets is discussed in detail. In contrast with the Schrödinger picture wave packet, the reflected part is so clearly defined that we can evaluate the reflection probability as a function of time.

F. Bunchaft, C.M. Chaves, W. Baltensperger