Wavepacket dynamics of the nonlinear Harper model

Gim Seng Ng, Tsampikos Kottos
2007 Physical Review B  
The destruction of anomalous diffusion of the Harper model at criticality, due to weak nonlinearity χ, is analyzed. It is shown that the second moment grows subdiffusively as ∼ t^α up to time t^*∼χ^γ. The exponents α and γ reflect the multifractal properties of the spectra and the eigenfunctions of the linear model. For t>t^*, the anomalous diffusion law is recovered, although the evolving profile has a different shape than in the linear case. These results are applicable in wave propagation
more » ... ough nonlinear waveguide arrays and transport of Bose-Einstein condensates in optical lattices.
doi:10.1103/physrevb.75.205120 fatcat:rtdxf7kjyvdhjmfh6gtc6zfj64