We study Bose-Einstein condensate in the combined presence of time modulated
optical lattice and harmonic trap in the mean-field approach. Through the
self-similar method, we show the existence of sinusoidal lattice modes in this
inhomogeneous system, commensurate with the lattice potential. A significant
advantage of this system is wide tunability of the parameters through chirp
management. The combined effect of the interaction, harmonic trap and lattice
potential leads to the generation of nonlinear resonances, exactly where the
matter wave changes its direction. When the harmonic trap is switched off, the
BEC undergoes a nonlinear compression for the static optical lattice potential.
For better understanding of chirp management and the nature of the sinusoidal
excitation, we investigate the energy spectrum of the condensate, which clearly
reveals the generation of nonlinear resonances in the appropriate regime. We
have also identified a classical dynamical phase transition occurring in the
system, where loss of superfluidity takes the superfluid phase to an insulating
state.Comment: 13 pages, 4 figures. arXiv admin note: text overlap with
arXiv:1008.184
