Novel robust characteristic for the flat-top bright wave in PT-symmetric higher-order Gross–Pitaevskii equation

The flat-top bright (FTB) as a novel type of soliton wave, which many characteristics have not been studied yet. This paper mainly searches some new features of FTB waves and discovers many differences with these usual features of solitons. The FTB soliton has not a effected by other external wave, we call it on robust wave. The Gross–Pitaevskii (GP) equation is an important and useful model in Bose–Einstein condensation (BEC). The PT-symmetric higher-order Gross–Pitaevskii (HOGP) equation has several kinds of potentials including Gaussian, harmonic and radial potentials, and it is a generalization GP equation. Then, some physically relevant solutions are derived, a kind of flat-top soliton solution is considered for the HOGP equation with Gaussian-harmonic-radial PT-symmetric potential. Especially, some novel flat-top bright (FTB) solitons are found, these FTB solitons can exist stably with Gaussian-harmonic-radial PT-symmetric potentials in a broad range. We investigate the interaction dynamics of between the FTB soliton and FTB soliton, the FTB soliton and bright soliton through addressing numerically. Intriguingly, the FTB solitons can admit some novel features and are different from these usual features of solitons, which have not a effected by other external wave. These results are useful for the possibility of some relative experiments and potential applications.