Yan Mi, DeSalvo B J, Ramachandhran B, Pu H, Killian T C
Department of Physics and Astronomy, Rice University, Houston, Texas 77251, USA.
Phys Rev Lett. 2013 Mar 22;110(12):123201. doi: 10.1103/PhysRevLett.110.123201. Epub 2013 Mar 20.
We demonstrate control of the collapse and expansion of an (88)Sr Bose-Einstein condensate using an optical Feshbach resonance near the (1)S(0)-(3)P(1) intercombination transition at 689 nm. Significant changes in dynamics are caused by modifications of scattering length by up to ± 10a(bg), where the background scattering length of (88)Sr is a(bg) = -2a(0) (1a(0) = 0.053 nm). Changes in scattering length are monitored through changes in the size of the condensate after a time-of-flight measurement. Because the background scattering length is close to zero, blue detuning of the optical Feshbach resonance laser with respect to a photoassociative resonance leads to increased interaction energy and a faster condensate expansion, whereas red detuning triggers a collapse of the condensate. The results are modeled with the time-dependent nonlinear Gross-Pitaevskii equation.
我们展示了利用在689纳米处(1)S(0)-(3)P(1)组合跃迁附近的光学费什巴赫共振来控制(88)Sr玻色-爱因斯坦凝聚体的坍缩和膨胀。动力学的显著变化是由散射长度改变高达±10a(bg)引起的，其中(88)Sr的背景散射长度为a(bg)= -2a(0)（1a(0)=0.053纳米）。在飞行时间测量后，通过凝聚体尺寸的变化来监测散射长度的变化。由于背景散射长度接近零，光学费什巴赫共振激光相对于光缔合共振的蓝失谐会导致相互作用能增加和凝聚体膨胀加快，而红失谐则会引发凝聚体的坍缩。结果用含时非线性格罗斯-皮塔耶夫斯基方程进行了模拟。
