We theoretically study the role of the mode structure of a multicomponent Bose–Einstein condensate (BEC) in the potential created by a nonlinear optical lattice. We describe a multisoliton complex (MSC) as a superposition of different fundamental soliton modes in the matter-wave system. Using a similarity transformation, we solve the nonlinear evolution equation of the multimode coupled matter-wave field and construct a set of analytical bright soliton solutions. A perturbation method is used to examine the linear stability of the constructed solitons. Based on these particular solutions, we numerically analyze the mode structure of a MSC. The results show that the periodicity causes a Bloch modulation in the envelopes of the density distribution. When different fundamental modes collide with each other in the nonlinear lattice, the collision-induced shifts, and the space-dependent modulation of external potentials change the density profile of the multimode soliton complex. Therefore, the mode structure, which is absent in a one-mode BEC, provides the possible multiscale modeling of the matter-wave field with extra degrees of freedom.
© 2013 Optical Society of America
Atomic and Molecular Physics
Original Manuscript: October 19, 2012
Revised Manuscript: December 20, 2012
Manuscript Accepted: January 29, 2013
Published: February 22, 2013
Jun Chen, Qiang Lin, and Yangjian Cai, "Multisoliton complexes of Bose–Einstein condensates in nonlinear optical lattices," J. Opt. Soc. Am. B 30, 691-699 (2013)