Localization in physical systems described by discrete nonlinear Schrodinger-type equations

摘要

A fundamental concept emerging from the combination of nonlinearity and discreteness is the existence of intrinsic localization in periodic extended systems. These inherent inhomogeneities are expected to be present in many complex materials characterized by interacting degrees of freedom leading to an effective nonlinearity. There is an increasing number of experimental indications of intrinsic localized modes in materials.In addition to the early example of acetanilide, more recently microscopic vibrational localization has been observed in the Raman spectra of the linear charge-transfer salt PtCl~2, as well as in time resolved pump-probe experiments in thin organic films and π-conjugated polymers. In the latter case, lattice energy localization following photo-excitation of polyacetylene has been theoretically predicted some time ago.