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Two kinds of multidimensional atom interferometers are demonstrated that are capable of measuring both the magnitude and direction of applied inertial forces. These interferometers, built from ultracold Bose-Einstein condensed rubidium atoms, use an original design that operates entirely within the Bloch bands of an optical lattice. Through time-dependent lattice position control, we realize Bloch oscillations in two dimensions and a vector atomic Michelson interferometer. Fits to the observed Bloch oscillations demonstrate the measurement of an applied acceleration of 2galong two axes, wheregis Earth’s gravitational acceleration. For the Michelson interferometer, we perform Bayesian inferencing from a 49-channel output by repeating experiments for two-axis accelerations and demonstrate vector parameter estimation. Accelerations can be measured from single experimental runs and do not require repeated shots to construct a fringe. The performance of our device is near the quantum limit for the interferometer size and quantum detection efficiency of the atoms.
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Measuring gravitational attraction with a lattice atom interferometer
Despite being the dominant force of nature on large scales, gravity remains relatively elusive to precision laboratory experiments. Atom interferometers are powerful tools for investigating, for example, Earth’s gravity, the gravitational constant, deviations from Newtonian gravity and general relativity. However, using atoms in free fall limits measurement time to a few seconds, and much less when measuring interactions with a small source mass. Recently, interferometers with atoms suspended for 70 s in an optical-lattice mode filtered by an optical cavity have been demonstrated. However, the optical lattice must balance Earth’s gravity by applying forces that are a billionfold stronger than the putative signals, so even tiny imperfections may generate complex systematic effects. Thus, lattice interferometers have yet to be used for precision tests of gravity. Here we optimize the gravitational sensitivity of a lattice interferometer and use a system of signal inversions to suppress and quantify systematic efects. We measure the attraction of a miniature source mass to be amass = 33.3 ± 5.6stat ± 2.7syst nm s−2, consistent with Newtonian gravity, ruling out ‘screened ffth force’ theories3,15,16 over their natural parameter space. The overall accuracy of 6.2 nm s−2 surpasses by more than a factor of four the best similar measurements with atoms in free fall. Improved atom cooling and tilt-noise suppression may further increase sensitivity for investigating forces at sub-millimetre ranges, compact gravimetry, measuring the gravitational Aharonov–Bohm effect and the gravitational constant, and testing whether the gravitational field has quantum properties.
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- PAR ID:
- 10525888
- Publisher / Repository:
- Nature
- Date Published:
- Journal Name:
- Nature
- Volume:
- 631
- Issue:
- 8021
- ISSN:
- 0028-0836
- Page Range / eLocation ID:
- 515 to 520
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
-
Accepted Manuscript
- Journal Article:
- https://doi.org/10.1038/s41586-024-07561-3
