玻色-费米气体量子简并光学偶极阱的设计

实现了将预冷却(温度约为1～2μK)的87 Rb和40 K原子装载到远红失谐的光学偶极力阱中,继而利用逐步降低光强的方法对其进行蒸发冷却,获得了87 Rb原子的玻色-爱因斯坦凝聚(BEC),并用协同冷却的方法得到了40 K原子的量子简并(DFG)。实验上通过光纤传输远红失谐激光束降低了光束指向性的抖动,又利用光强反馈伺服系统抑制远红失谐激光的强度抖动,提高了获得玻色-爱因斯坦凝聚和简并费米气体的重复性和稳定性。实验上得到玻色-爱因斯坦凝聚的原子数达8.48×105个,简并费米气体的原子数量约为3.34×106个。     

基于信息熵的空战目标威胁评估

空战目标威胁评估是协同多目标攻击空战决策的关键技术之一.针对传统空战目标威胁评估方法在确定权重系数方面的缺陷和不足,提出了运用信息熵方法来解决空战目标威胁评估问题.给出了信息熵方法确定威胁指标权重的具体步骤,建立了基于信息熵的空战目标威胁评估模型,并进行了仿真研究,仿真结果表明该方法是合理和有效的.     

Feshbach resonances in an ultracold mixture of 87Rb and 40K

We report the experimental preparations of the absolute ground states of ⁸⁷Rb and ⁴⁰K atoms (| F=1, m_F=1,〉+ |F=9/2, m_F=-9/2,〉) by means of the radio-frequency and microwave adiabatic rapid passages, and the observation of magnetic Feshbach resonances in an ultracold mixture of bosonic ⁸⁷Rb and fermionic ⁴⁰K atoms between 0 T and 6.0 × 10^-2 T, including 7 homonuclear and 4 heteronuclear Feshbach resonances. The resonances are identified by the abrupt trap loss of atoms induced by the strong inelastic three-body collisions. These Feshbach resonances should enable the experimental control of interspecies interactions.     

Evaporative cooling of 87Rb atoms into Bose-Einstein condensate in an optical dipole trap

We create a Bose-Einstein condensate(BEC) of 87Rb atoms by runaway evaporative cooling in an optical trap.Two crossed infrared laser beams with a wavelength of 1064 nm are used to form an optical dipole trap.After precooling the atom samples in a quadrupole-Ioffe configuration(QUIC) trap under 1.5 μK by radio-frequency(RF) evaporative cooling,the samples are transferred into the center of the glass cell,then loaded into the optical dipole trap with 800 ms.The pure condensate with up to 1.5×105 atoms is obtained over 1.17 s by lowering the power of the trap beams.