Testing the Universality of Free Fall by Comparing the Atoms in Different 

Hyperfine States with Bragg Diffraction

Ke Zhang, Min-Kang Zhou, Yuan Cheng, Le-Le Chen, Qin Luo, Wen-Jie Xu, Lu-Shuai Cao, Xiao-Chun Duan, Zhong-Kun Hu

We perform a precision atom interferometry experiment to test the universality of free fall. Our experiment employs the Bragg atom interferometer with ⁸⁷Rb atoms either in hyperfine state |F = 1, m_F = 0> or |F = 2, m_F = 0>, and the wave packets in these two states are diffracted by one pair of Bragg beams alternatively, which is helpful for suppressing common-mode systematic errors. We obtain an Eötvös ratio η₁₋₂ = (0.9 ± 2.7) ×10⁻¹⁰, and set a new record on the precision with improvement of nearly 5 times. This measurement also provides constraint on the difference of the diagonal terms of the mass-energy operator.

期刊名：Chinese Physics Letters

期/卷：Volume 37

页码：043701

发表时间：2020.03.24

DOI: 10.1088/0256-307X/37/4/043701