Atom-Based Test of the Equivalence Principle
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We describe a test of the equivalence principle with quantum probe particles based on atom interferometry. For the measurement, a light pulse atom interferometer based on the diffraction of atoms from effective absorption gratings of light has been developed. A differential measurement of the Earth’s gravitational acceleration g for the two rubidium isotopes 85Rb and 87Rb has been performed, yielding a difference Δg/g=(1.2±1.7)×10−7. In addition, the dependence of the free fall on the relative orientation of the electron to the nuclear spin was studied by using atoms in two different hyperfine states. The determined difference in the gravitational acceleration is Δg/g=(0.4±1.2)×10−7. Within their experimental accuracy, both measurements are consistent with a free atomic fall that is independent from internal composition and spin orientation.
KeywordsQuantum mechanics Gravity Equivalence principle Atom interferometer
- See, e.g., P. Berman, Atom Interferometry (Academic Press, San Diego, 1997). Google Scholar
- C. Lämmerzahl, in Proceedings of the International School of Cosmology and Gravitation, Course XV, ed. by P.G. Bergmann et al. (World Scientific, Singapore, 1998) and references therein Google Scholar
- K. Nordtvedt, gr-qc/0212044 (2002)
- See, e.g. the contributions by B. Schutz T. Damour, Space Sci. Rev. (2009, this issue) Google Scholar