Electric Rydberg atom interferometry for gravity measurements with positronium

The standard model predicts symmetry between the acceleration due to gravity, g, for matter and antimatter. However, rigorous experimental tests of this are limited. Experiments to measure g for purely leptonic positronium atoms can complement efforts involving antihydrogen at CERN [1]. In its ground state positronium has an annihilation lifetime of 142 ns, making precise measurement of g unfeasible. However, in high Rydberg states annihilation is suppressed, and the excited atoms can have lifetimes >10 μs [2]. To exploit these extended lifetimes for interferometric measurements of g we have developed an electric analogue of magnetic Stern-Gerlach interferometry [3] that can be implemented for atoms in Rydberg states [4]. This involves preparing the atoms in superpositions of Rydberg states with different static electric dipole moments, and exerting state-dependent forces on them using inhomogeneous electric fields. Here we describe the design of this full-loop interferometer and how it can be operated to measure g in experiments with helium and, in the longer term, positronium.



[1] Anderson, E.K., Baker, C.J., Bertsche, W. et al., Nature 621, 716–722 (2023)

[2] A. Deller, B. S. Cooper, S. D. Hogan and D. B. Cassidy, Phys. Rev. A 93, 062513 (2016)

[3] Y. Margalit, O. Dobkowski, Z. Zhou, O. Amit, Y. Japha, S. Moukouri, D. Rohrlich, A. Mazumdar, S. Bose, C. Henkel, R. Folman, Sci. Adv 7, 22 (2021)

[4] J. E. Palmer and S. D. Hogan, Phys. Rev. Lett 122, 250404 (2019); J. D. R. Tommey and S. D. Hogan, Phys. Rev. A 104, 033305 (2021)