Localization and damping of macroscopic oscillation in coupled Gross-Pitaevskii equations without self-interaction

In Bose-Einstein condensates, quantum phenomena appear in a macroscopic scale. The Gross-Pitaevskii (GP) equation describes the dynamics of weakly interacting Bose-Einstein condensates. The GP equation has a form of the Schroedinger equation with self-interaction. A localized solution called soliton appears when the dispersion effect and attractive interaction are balanced. The coupled GP equations are used to describe some mixtures of Bose-Einstein condensates. In this paper, we will show some numerical results of coupled GP equations without self-interaction, which has a form of nonlinearly coupled Schroedinger equations. We demonstrate a transition between the localized and delocalized states, and the appearance of dissipation or the damping of a macroscopic oscillation caused by the mutual interaction. (author)