2016, 65 (5): 050501.
We study a (1+1)-dimensional variable-coefficient Gross-Pitaevskii equation with parabolic potential. A similarity transformation connecting the variable-coefficient Gross-Pitaevskii equation with the standard nonlinear Schrödinger equation is constructed. According to this transformation and solutions of the standard nonlinear Schrodinger equation, we obtain exact rogue wave solutions of variable-coefficient Gross-Pitaevskii equation with parabolic potential. In this solution, a Galilean transformation is used such that the center of optical pulse is Xc = v(T-T0) while the Galilean transformation was not used in previous analysis. By the Galilean transformation, the parameter T0 is added into the solution. It is found that the parameter T0 is important to control the excitations of rogue waves. Moreover, the parameters a1 and a2 in solution are complex parameters which can modulate the behaviors of rogue waves. If they are restricted to real numbers, we can obtain some well-known rogue wave solutions. If the parameter a2 =-1/12, we can have a second-order rogue wave solution. If the parameter a2 is a complex number, the solution can describe rogue wave triplets. Here two kinds of rogue wave triplets, namely, rogue wave triplets I and II are presented. For rogue wave triplet I, at first, two first-order rogue waves on each side are excited, and then a first-order rogue wave in the middle is excited with the increase of time. On the contrary, for rogue wave triplet II, a first-order rogue wave in the middle is initially excited, and then two first-order rogue waves on each side are excited with the increase of time.#br#From these solutions, the controls for the excitations of rogue waves, such as the restraint, maintenance and postponement, are investigated in a system with an exponential-profile interaction. In this system, by modulating the relation between the maximum of accumulated time Tmax and the peak time T0 (or TI,TII), we realize the controls of rogue waves. When Tmax > T0 (or TI,TII), rogue wave is excited quickly, and the atom number of condensates increases; when Tmax = T0 (or TI,TII), rogue wave is excited to the maximum amplitude, then maintains this magnitude for a long time, and the atom number of condensates also increases; when Tmax T0 (or TI,TII), the threshold of exciting rogue wave is never reached, thus the complete excitation is restrained, and the atom number of condensates reduces. These results can be used to understand rogue waves better, that is, besides their "appearing from nowhere and disappearing without a trace", rogue waves can be controlled as discussed by a similar way in this paper. These manipulations for rogue waves give edification on theory and practical application.