In-orbit test of the weak equivalence principle with atom interferometry
- Dan-Fang Zhang
- Jing-Ting Li
- Wen-Zhang Wang
- Wei-Hao Xu
- Jia-Yi Wei
- Xiao Li
- Yi-Bo Wang
- Dong-Feng Gao
- Jia-Qi Zhong
- Biao Tang
- Lin Zhou
- Run-Bing Li
- Huan-Yao Sun
- Qun-Feng Chen
- Lei Qin
- Mei-Zhen An
- Zong-Feng Li
- Shu-Quan Wang
- Xiao-Xiao Guo
- Yao Tian
- Xi-He Yu
- Hong-En Zhong
- Xi Chen
- Jin Wang
- Ming-Sheng Zhan
2026-08-28
The weak equivalence principle (WEP) is a central pillar of general relativity. Its precise test with quantum systems in space offers a unique window onto new physics. Here, we report an in-orbit quantum test of the WEP. A dual-species ( 85 Rb/ 87 Rb) atom interferometer is realized aboard the China Space Station. Methods of platform motion suppression, fluorescence detection switching, and two-photon detuning switching are developed to eliminate phase noise and improve measurement accuracy. A test uncertainty of 2.8 × 10 −8 is obtained from 280 days of WEP test data, and a test result of (−2.7 ± 4.7) × 10 −7 is achieved after error estimation. This improves prior atom-interferometric WEP tests in microgravity by three orders of magnitude. This work paves the way for space-borne quantum inertial sensors and their application to future fundamental physics in space.