Dipartimento di Fisica e Astronomia and LENS, Università di Firenze-INFN Sezione di Firenze, Via Sansone 1, Sesto Fiorentino 50019, Italy.
European Space Agency, Keplerlaan 1-P.O. Box 299, Noordwijk ZH 2200 AG, The Netherlands.
Nat Commun. 2017 Jun 1;8:15529. doi: 10.1038/ncomms15529.
The Einstein equivalence principle (EEP) has a central role in the understanding of gravity and space-time. In its weak form, or weak equivalence principle (WEP), it directly implies equivalence between inertial and gravitational mass. Verifying this principle in a regime where the relevant properties of the test body must be described by quantum theory has profound implications. Here we report on a novel WEP test for atoms: a Bragg atom interferometer in a gravity gradiometer configuration compares the free fall of rubidium atoms prepared in two hyperfine states and in their coherent superposition. The use of the superposition state allows testing genuine quantum aspects of EEP with no classical analogue, which have remained completely unexplored so far. In addition, we measure the Eötvös ratio of atoms in two hyperfine levels with relative uncertainty in the low 10, improving previous results by almost two orders of magnitude.
爱因斯坦等效原理（EEP）在理解引力和时空方面起着核心作用。在其弱形式，或弱等效原理（WEP）中，它直接暗示惯性质量和引力质量之间的等价性。在需要用量子理论来描述测试体的相关性质的情况下验证这一原理，具有深远的意义。在这里，我们报告了一种新的原子等效原理检验：在重力梯度仪配置中使用布拉格原子干涉仪，比较在两种超精细状态下制备的铷原子的自由落体，以及它们的相干叠加。超叠加态的使用允许对迄今为止尚未得到充分探索的 EEP 的真正量子方面进行测试，没有经典类比。此外，我们还以低于 10 的相对不确定度测量了两个超精细能级中原子的埃托夫比值，这比以前的结果提高了近两个数量级。
