{"paper":{"title":"Test of the universality of free fall with atoms in different spin orientations","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","headline":"","cross_cats":["physics.atm-clus"],"primary_cat":"physics.atom-ph","authors_text":"Cheng-Gang Shao, Feng Xiong, Jun Luo, Ke Zhang, Min-Kang Zhou, Wen-Jie Xu, Xiao-Bing Deng, Xiao-Chun Duan, Yao-Yao Xu, Zhong-Kun Hu","submitted_at":"2016-02-20T07:48:16Z","abstract_excerpt":"We report a test of the universality of free fall (UFF) by comparing the gravity acceleration of the $^{87}$Rb atoms in $m_F=+1$ versus that in $m_F=-1$, where the corresponding spin orientations are opposite. A Mach-Zehnder-type atom interferometer is exploited to sequentially measure the free fall acceleration of the atoms in these two magnetic sublevels, and the resultant E$\\rm{\\ddot{o}}$tv$\\rm{\\ddot{o}}$s ratio is ${\\eta _S} =(0.2\\pm1.2)\\times 10^{-7}$. This also gives an upper limit of $1.1\\times 10^{-21}$ GeV/m for possible gradient field of the spacetime torsion. The interferometer usin"},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"1602.06377","kind":"arxiv","version":1},"verdict":{"id":null,"model_set":{},"created_at":null,"strongest_claim":"","one_line_summary":"","pipeline_version":null,"weakest_assumption":"","pith_extraction_headline":""},"references":{"count":0,"sample":[],"resolved_work":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57","internal_anchors":0},"formal_canon":{"evidence_count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"author_claims":{"count":0,"strong_count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"builder_version":"pith-number-builder-2026-05-17-v1"}