Atomic Structure

Fei Li, Zhijian He, Wenwu Li

Abstract We study the spatial structure of a Bose–Einstein condensate (BEC) with a space-dependent s-wave scattering length in a combined trap. There exists a space-dependent nonlinear atomic current in the system. The atomic current has an important influence on the spatial structure of the BEC. Research findings reveal that a large chemical potential can effectively suppress the chaotic spatial structure in the BEC system. Due to the large chemical potential, a strong atomic current is necessary to make the system lose its periodic spatial structure and lead the system into a chaotic spatial structure. But when the atomic current intensity exceeds a critical value, the chaotic spatial structure of the BEC will be completely eliminated and the system will always be kept in a series of single-periodic states as the atomic current becomes stronger. For a very weak atomic current, the spatial structure of the BEC is very sensitive to the intensity of the atomic current and a very small change of the intensity can dramatically change the spatial structure of the BEC. The effects of the combined trap parameters on the spatial structure of BECs are also discussed.

Sune R. Svanberg

Bin Wang, Yan Chen

We investigate the band structure and the dynamics of Bose-Einstein condensates in a triple-well trap, which are located in a high-finesse optical cavity. For the noninteracting atoms, the band structure of the eigenenergies are obtained using the numerical methods under the mean-field approximation. It is demonstrated that the energy band structure is strongly dependent on the value of reduced cavity detuning. Under some conditions, the atomic band structure develops loop structures and swallowtail structure, which mean the atom-cavity system exhibits bistability. We attribute the appearance of new states to the nonlinearity of the cavity-field-induced tilt. For the interacting atoms, the structure of the eigenenergy band appears more complicated for the interaction between atoms.

Hassan Raza

NORMAN R. CAMPBELL

Lin Zhang, Guojian Yang

The atomic density and atomic polarization spatial structures in pump-probe driven atomic ensembles are directly demonstrated by numerical simulations under the low atomic saturation regime. The different roles of these structures in atomic emission are distinguished by focusing on the evolution of the collective coherence parameters of the atoms.