Variational Approach to Study PT-Symmetric Solitons in a Bose-Einstein Condensate with Non-locality of Interactions

摘要

Considering the non-locality of interactions in a Bose-Einstein condensate,the existence and stability of solitons subject to a PT-symmetric potential are discussed.In the framework of the variational approach,we investigate how the non-locality of interactions affects the self-localization and stability of a condensate with attractive two-body interactions.The results reveal that the non-locality of interactions dramatically influences the shape,width,and chemical potential of the condensate.Analytically variational computation also predicts that there exists a critical negative non-local interaction strength (pc.＜ 0) with each fixed two-body interaction (g0 ＜ 0),and there exists no bright soliton solution for p0 ＜ pc.Furthermore,we study the effect of the non-locality interactions on the stability of the solitons using the Vakhitov-Kolokolov stability criterion.It is shown that for a positive non-local interaction (p0 ＞ 0),there always exist stable bright solitons in some appropriate parameter regimes.