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arXiv:1503.00433 · Physical Review Letters

Test of the Universality of Free Fall with Atoms in Different Spin Orientations

Xiao‐Chun Duan, Xiao-Bing Deng, Min-Kang Zhou, Ke Zhang, Wenjie Xu, Feng Xiong, Yaoyao Xu, Cheng-Gang Shao, Jun Luo, Zhong-Kun Hu

Published Jul 6, 2016• 137 citations
arXivHTMLPDF

Abstract

We report a test of the universality of free fall by comparing the gravity acceleration of the ^{87}Rb atoms in m_{F}=+1 versus those in m_{F}=-1, of which the corresponding spin orientations are opposite. A Mach-Zehnder-type atom interferometer is exploited to alternately measure the free fall acceleration of the atoms in these two magnetic sublevels, and the resultant Eötvös ratio is η_{S}=(0.2±1.2)×10^{-7}. This also gives an upper limit of 5.4×10^{-6} m^{-2} for a possible gradient field of the spacetime torsion. The interferometer using atoms in m_{F}=±1 is highly sensitive to the magnetic field inhomogeneity. A double differential measurement method is developed to alleviate the inhomogeneity influence, of which the effectiveness is validated by a magnetic field modulating experiment.

DOI
10.1103/physrevlett.117.023001

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