Delocalization in One-Dimensional Tight-Binding Models with Fractal Disorder

In the present work, we investigated the correlation-induced localization-delocalization transition in the one-dimensional tight-binding model with fractal disorder. We obtained a phase transition diagram from localized to extended states based on the normalized localization length by controlling the correlation and the disorder strength of the potential. In addition, the transition of the diffusive property of wavepacket dynamics is shown around the critical point.Comment: 9 pages, 11 figure

Wavepacket Dynamics in One-Dimensional System with Long-Range Correlated Disorder

We numerically investigate dynamical property in the one-dimensional tight-binding model with long-range correlated disorder having power spectrum $1/f^\alpha$ ($\alpha:$spectrum exponent) generated by Fourier filtering method. For relatively small $\alpha<\alpha_c(=2)$ time-dependence of mean square displacement (MSD) of the initially localized wavepacket shows ballistic spread and localizes as time elapses. It is shown that $\alpha-$dependence of the dynamical localization length (DLL) determined by the MSD exhibits a simple scaling law in the localization regime for the relatively weak disorder strength $W$. Furthermore, scaled MSD by the DLL almost obeys an universal function from the ballistic to the localization regime in the various combinations of the parameters $\alpha$ and $W$.Comment: 4 pages, 4 figure

Time-reversal Characteristics of Quantum Normal Diffusion

This paper concerns with the time-reversal characteristics of intrinsic normal diffusion in quantum systems. Time-reversible properties are quantified by the time-reversal test; the system evolved in the forward direction for a certain period is time-reversed for the same period after applying a small perturbation at the reversal time, and the separation between the time-reversed perturbed and unperturbed states is measured as a function of perturbation strength, which characterizes sensitivity of the time reversed system to the perturbation and is called the time-reversal characteristic. Time-reversal characteristics are investigated for various quantum systems, namely, classically chaotic quantum systems and disordered systems including various stochastic diffusion systems. When the system is normally diffusive, there exists a fundamental quantum unit of perturbation, and all the models exhibit a universal scaling behavior in the time-reversal dynamics as well as in the time-reversal characteristics, which leads us to a basic understanding on the nature of quantum irreversibility.Comment: 21pages, 25figure