Dark Solitons in Bose-Einstein Condensates: Theory

淳一 家田

Tang Zheng-Hua, Yan Jia-Ren, Linghong Liu

The dissipative dynamic stability is investigated of dark solitons in elongated Bose–Einstein condensates that can be described by the Gross–Pitaevskii equation including an additional term. Based on the direct perturbation theory for the nonlinear Schrodinger equation, the dependence of the soliton velocity on time is explicitly given, and the shape of dark solitons remaining unchanged under the dissipative condition is confirmed theoretically for the first time. It is found that the dynamically stable dark solitons turn out to be thermodynamically unstable.

P. G. Kevrekidis

F. Kh. Abdullaev, Josselin C. Garnier

Kai Bongs, Sven Burger, D. Hellweg +7 more

Experimental and numerical studies of the velocity field of dark solitons in Bose–Einstein condensates are presented. The formation process after phase imprinting as well as the propagation of the emerging soliton are investigated using spatially resolved Bragg spectroscopy of soliton states in Bose–Einstein condensates of 87 Rb. A comparison of experimental data to results from numerical simulations of the Gross–Pitaevskii equation clearly identifies the flux underlying a dark soliton propagating in a Bose–Einstein condensate. The results allow further optimization of the phase imprinting method for creating collective excitations of Bose–Einstein condensates.

Georgios Theocharis, P. G. Kevrekidis, Hector E. Nistazakis +2 more