School of Physics, Northwest University, Xi'an 710127, China.
Shaanxi Key Laboratory for Theoretical Physics Frontiers, Xi'an 710127, China.
Phys Rev E. 2019 Aug;100(2-1):022212. doi: 10.1103/PhysRevE.100.022212.
We investigate nondegenerate bound-state solitons systematically in multicomponent Bose-Einstein condensates, through developing the Darboux transformation method to derive exact soliton solutions analytically. In particular, we show that bright solitons with nodes correspond to the excited bound states in effective quantum wells, in sharp contrast to the bright solitons and dark solitons reported before (which usually correspond to ground state and free state, respectively). We further demonstrate that bound-state solitons with nodes are induced by incoherent superposition of solitons in different components. Moreover, we reveal that the interactions between these bound-state solitons are usually inelastic, caused by the incoherent interactions between solitons in different components and the coherent interactions between solitons in the same component. Additionally, the detailed spectral stability analysis demonstrates the stability of nondegenerate bound-state solitons. The bound-state solitons can be used to study many different physical problems, such as beating dynamics, spin-orbit coupling effects, quantum fluctuations, and even quantum entanglement states.
我们通过发展达布变换方法来系统地研究多分量玻色-爱因斯坦凝聚中的非简并束缚态孤子，从而解析地得到孤子精确解。特别地，我们表明，具有节点的亮孤子对应于有效量子阱中的激发束缚态，与之前报道的亮孤子和暗孤子形成鲜明对比（它们通常分别对应于基态和自由态）。我们进一步证明，具有节点的束缚态孤子是由不同分量中孤子的非相干叠加引起的。此外，我们揭示了这些束缚态孤子之间的相互作用通常是非弹性的，这是由不同分量中孤子的非相干相互作用以及同一分量中孤子的相干相互作用引起的。此外，详细的谱稳定性分析证明了非简并束缚态孤子的稳定性。束缚态孤子可用于研究许多不同的物理问题，例如拍频动力学、自旋轨道耦合效应、量子涨落，甚至量子纠缠态。
