JILA, National Institute of Standards and Technology and University of Colorado, and Department of Physics, University of Colorado, Boulder, Colorado 80309-0440, USA.
Phys Rev Lett. 2012 Dec 7;109(23):230403. doi: 10.1103/PhysRevLett.109.230403. Epub 2012 Dec 4.
We report the measurement of the anisotropic ac polarizability of ultracold polar (40)K(87)Rb molecules in the ground and first rotationally excited states. Theoretical analysis of the polarizability agrees well with experimental findings. Although the polarizability can vary by more than 30%, a "magic" angle between the laser polarization and the quantization axis is found where the polarizability of the |N=0,m(N)=0> and the |N=1,m(N)=0> states match. At this angle, rotational decoherence due to the mismatch in trapping potentials is eliminated, and we observe a sharp increase in the coherence time. This paves the way for precise spectroscopic measurements and coherent manipulations of rotational states as a tool in the creation and probing of novel quantum many-body states of polar molecules.
我们报告了对超冷极性 (40)K(87)Rb 分子在基态和第一转动激发态的各向异性交流极化率的测量。极化率的理论分析与实验结果吻合良好。尽管极化率可能变化超过 30%，但我们发现激光偏振和量子化轴之间存在一个“魔法”角度，在此角度下 |N=0,m(N)=0> 和 |N=1,m(N)=0> 态的极化率相匹配。在这个角度下，由于陷阱势的不匹配导致的转动退相干被消除，我们观察到相干时间的急剧增加。这为精确的光谱测量和转动态的相干操纵铺平了道路，作为创建和探测极性分子新的量子多体态的工具。
