Trap Effects

Nan Yu, HANS G. DEHMELT

Micromotion is the driven motion of trapped ions in rf traps. In practical traps, the micromotion is often greatly enhanced due to “dirty effects” such as stray dc fields from surface patch effects and/or rf phase differences between the endcaps of a quadrupole trap. Large micromotions can have adverse effects on precision measurements and quantum experiments that the trapped ions are best suited for. We present here a new approach to reduce and eliminate the enhanced micromotion. The approach uses a novel Paul-Straubel-Kingdon trap in which ions are loaded indirectly to avoid contamination of the trap surfaces.

Momčilo M. Gavrilov

Ying-Cheng Chen, Wenbin Lin, Hsuin-Chia Hsue +2 more

We have experimentally studied the effect of the trapping laser linewidth on the number of trapped atoms in a magneto-optical trap (MOT). Our data show that a significant number of the atoms can still be trapped in the MOT, even when the trapping laser linewidth is larger than the natural linewidth of the excited state of the driving transition.

Lawrence Cranberg

Abhik Kumar Saha, Kingshuk Adhikary, Subhanka Mal +2 more

Abstract We theoretically study the effects of trap-confinement and interatomic interactions on Josephson oscillations (JO) and macroscopic quantum self-trapping (MQST) for a Bose–Einstein condensate confined in a trap which has a symmetric double-well potential along z -axis and 2D harmonic potentials along x - and y -axis. We consider three types of model interaction potentials: contact, long-range dipolar and finite-range potentials. Our results show that by changing the aspect ratio between the axial and radial trap sizes, one can induce a transition from JO to MQST for contact interactions with a small scattering length. For long-range dipolar interatomic interactions, we analyze transition from Rabi to Josephson regime and Josephson to MQST regime by changing the aspect ratio of the trap for a particular dipolar orientation. For a finite-range interaction, we study the effects of relatively large scattering length and effective range on JO and MQST. We show that JO and MQST are possible even if scattering length is relatively large, particularly near a narrow Feshbach resonance due to the finite-range effects.