Effect of external magnetic field on the shift of resonant frequency in photoassociation of ultracold Cs atoms*

Project supported by the National Key Research and Development Program of China (Grant No. 2017YFA0304203), the Chang Jiang Scholars and Innovative Research Team in the University of the Ministry of Education of China (Grant No. IRT13076), the National Natural Science Foundation of China (Grant Nos. 61722507, 61675121, 61705123, and 11434007), the Fund for Shanxi 1331 Project Key Subjects Construction, China, and the Applied Basic Research Project of Shanxi Province, China (Grant No. 201701D221002).
Li Pengwei1, Li Yuqing1, 2, †, Feng Guosheng1, Wu Jizhou1, 2, Ma Jie1, 2, Xiao Liantuan1, 2, Jia Suotang1, 2
       

(a) Illustration of single channel square-well potential with the tunable depth. The horizontal line in the outer region represents the potential energy U = 0. An external magnetic field can alter the scattering length of colliding atoms in the outer region and then induces the variation of the atomic wavefunction, whose continuity at the boundary point R0 requires the tunable-depth square well potential indicated by the dashed lines. As a result, the magnetic field can change the density of the atomic pairs in the short internuclear distance where PA occurs. (b) The slope of the frequency shift derived from Fig. 3 as a function of magnetic field. The black diamond is experimental data and the red solid line is the theoretical result.