AUTHOR=Zhou Lin , Yan Si-Tong , Ji Yu-Hang , He Chuan , Jiang Jun-Jie , Hou Zhuo , Xu Run-Dong , Wang Qi , Li Zhi-Xin , Gao Dong-Feng , Liu Min , Ni Wei-Tou , Wang Jin , Zhan Ming-Sheng 

TITLE=Toward a high-precision mass–energy test of the equivalence principle with atom interferometers

JOURNAL=Frontiers in Physics

VOLUME=10

YEAR=2022

URL=https://www.frontiersin.org/journals/physics/articles/10.3389/fphy.2022.1039119

DOI=10.3389/fphy.2022.1039119

ISSN=2296-424X

ABSTRACT=<p>The equivalence principle (EP) is a basic assumption of the general relativity. The quantum test of the equivalence principle with atoms is an important way to examine the applicable scope of the current physical framework so as to discover new physics. Recently, we extended the traditional pure mass or energy tests of the equivalence principle to the joint test of mass–energy by atom interferometry (<italic>Zhou et al.,Phys.Rev.A 104,022822</italic>). The violation parameter of mass is constrained to <italic>η</italic><sub>0</sub> = (−0.8 ± 1.4) × 10<sup>–10</sup> and that of internal energy to <italic>η</italic><sub><italic>E</italic></sub> = (0.0 ± 0.4) × 10<sup>–10</sup> per reduced energy ratio. Here, we first briefly outline the joint test idea and experimental results, and then, we analyze and discuss how to improve the test accuracy. Finally, we report the latest experimental progress toward a high-precision mass–energy test of the equivalence principle. We realize atom interference fringes of 2<italic>T</italic> = 2.6 s in the 10-m long-baseline atom interferometer. This free evolution time <italic>T</italic>, to the best of our knowledge, is the longest duration realized in the laboratory, and the corresponding resolution of gravity measurement is 4.5 × 10<sup>−11</sup> g per shot.</p>