Spreading and localization of wavepackets in disordered wires in a magnetic field

We study the localization properties of wavepackets in disordered wires in a magnetic field. A formula for the steady-state wave function at the crossover regime from preserved to broken time-reversal symmetry is proposed, which is in excellent agreement with our numerical data. In contrast to a recent supersymmetry approach the extracted asymptotic decay rate of the steady state changes smoothly in the crossover regime. Finally, we investigate fluctuation properties around the steady state and find a scaling for the variance of the wavepacket which also shows a smooth transition due to the magnetic field.