Quantum diffusion in the one-dimensional quasi-periodic mosaic lattice
Quantum diffusion in the one-dimensional quasi-periodic Aubry-André-Harper(AAH)mosaic lattice model is studied based on the tight-binding Hamiltonian framework.The modulation effect of the quasi-periodic modulation potential(λ)on the extended states,localized states and mobility edges in the model is deeply investigated by calculating the eigen-energy,eigen-wave function and lattice participation number of the system.The results show that extended states,localized states and critical states exist at the same time in the AAH mosaic lattice,and increasing the λ strength makes the quantum states shift from the extended states to the localized states,change the position of the mobility edges,shrink the number of ex-tended states(Ne)and expand the number of localized states accordingly.By investigating the quantum diffusion in the AAH mosaic lattice deeply,it is found that the quantum diffusion always has a ballistic mo-tion,where the rate v is inversely proportional to λ.The Ne can be estimated from the positions of mobility edges which is found to be inversely proportional to λ.The ballistic quantum diffusion rate and Ne have the same dependence on the λ strength,indicating that the ballistic motion in the system originates from the contribution of the extended states.The Ne decreases with the increase of λ,which leads to a corresponding decrease in the quantum diffusion rate.The results will provide the theoretical guidance for modulating bal-listic quantum diffusion.
Anderson localizationAAH modelmobility edgequantum diffusion
万方数据
维普
