Matter-Wave Solitons in a Multi-Component Bose-Einstein Condensate(Quantum Field Theories: Fundamental Problems and Applications)

Emmanuel Kengne, Wu‐Ming Liu

淳一 家田

Zhong-Zhou Lan

Abstract Spinor Bose–Einstein condensates (BECs) are formed when atoms in the multi-component BECs possess single hyperfine spin states but retain internal spin degrees of freedom. This study concentrates on a (1+1)-dimensional three-couple Gross–Pitaevskii system to depict the macroscopic spinor BEC waves within the mean-field approximation. Regarding the distribution of the atoms corresponding to the three vertical spin projections, a known binary Darboux transformation is utilized to derive the N matter-wave soliton solutions and triple-pole matter-wave soliton solutions on the zero background, where N is a positive integer. For those multiple matter-wave solitons, the asymptotic analysis is performed to obtain the algebraic expressions of the soliton components in the N matter-wave solitons and triple-pole matter-wave solitons. The asymptotic results indicate that the matter-wave solitons in the spinor BECs possess the property of maintaining their energy content and coherence during the propagation and interactions. Particularly, in the N matter-wave solitons, each soliton component contributes to the phase shifts of the other soliton components; and in the triple-pole matter-wave solitons, stable attractive forces exist between the different matter-wave soliton components. Those multiple matter-wave solitons are graphically illustrated through three-dimensional plots, density plot and contour plot, which are consistent with the asymptotic analysis results. The present analysis may provide the explanations for the complex natural mechanisms of the matter waves in the spinor BECs, and may have potential applications in designs of atom lasers, atom interferometry and coherent atom transport.

Paulsamy Muruganandam, M. Lakshmanan

This chapter focuses on exploring localized excitations in the variable coefficient nonlinear Schrodinger (NLS) equation and its generalizations. The motivation comes from the fact that the NLS equation and its variants appear in several branches/topics of physics, including nonlinear optics and Bose-Einstein condensates (BECs). The chapter reviews critically the variety of matter wave solitons and their interactions in single- and multi-component Bose-Einstein condensates. It provides a brief overview of the mean Gross- Pitaevskii (GP) equation, derivation of the one-dimensional GP equation, and mapping of the 1D GP equation to the standard NLS equation. The chapter discusses matter wave single and multi bright and dark solitons of Bose– Einstein condensates with varying trap potentials and atomic interactions. It shows various solitons solutions of multi-component BECs described by the two coupled GP equations. In this case, the coupled GP equation has been mapped onto a two coupled NLS equation.

Chen Xue-hang

As a coherent matter wave,the Bose-Einstein condensate(BEC) provides a playground for the investigation of the macroscopic quantum phenomenon.The nonlinear optical lattice,which is consisted of two counter-propagating laser beams,is a powerful and widely used tool for the controlling of the dynamics of the coherent matter wave.In view of the potential applications of BEC,two or more independently grown condensates provide extra controllable degrees of freedom and can be used in many areas,such as quantum metrology and quantum computation.In this paper,a multi-mode description is introduced to characterize the multi-component coherent matter wave.To determine the evolution property of the multi-mode matter wave in a nonlinear optical lattice,we solve the multi-mode coupled nonlinear equations.A set of analytical bright soliton solutions are constructed with a similarity transformation.

P. G. Kevrekidis