Breathing solitons induced by collision in dipolar Bose–Einstein condensates

We numerically study the breathing dynamics induced by collision between bright solitons in one-dimensional Bose–Einstein condensates with strong dipole–dipole interaction. This breathing phenomenon is closely related to the after-collision short-lived attraction of solitons induced by the dipolar effect. The initial phase difference of solitons leads to the asymmetric dynamics after collision, which is manifested in their different breathing amplitude, breathing frequency, and atom number. We clarify that the asymmetry of breathing frequency is directly induced by the asymmetric atom number, rather than initial phase difference. Moreover, a collision between breathing solitons can produce new after-two-collision breathing solitons, whose breathing amplitude can be adjusted and reaches the maximum (or minimum) when the peak–peak (or dip–dip) collision happens. (paper)