Theory of quantum nonlinear localized modes in quantum lattices

✍ Scribed by Shozo Takeno; Mari Kubota; Kazuko Kawasaki

• Publisher: Elsevier Science
• Year: 1998
• Tongue: English
• Weight: 502 KB
• Volume: 113
• Category: Article
• ISSN: 0167-2789
• DOI: 10.1016/s0167-2789(97)00290-x

✦ Synopsis

A theory of quantum nonlinear localized modes is developed for three kinds of spatially discrete quantum systems, Bose lattices. Heisenberg spin systems and Frenkel excitons, by employing the coherent state path integral formulation. Applying the stationary-phase approximation leads to nonlinear lattice equations in c-number forms, in which the intrinsic nonlinearity of the quantum systems is incorporated to all orders. The general theory is illustrated by solving the obtained nonlinear equations both analytically and numerically to show the existence of stationary self-localized magnons in one-dimensional Heisenberg antiferromagnets and moving nonlinear localized modes in two-dimensional Heisenberg ferromagnets containing a hole.