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Resolving the gravitational redshift across a millimetre-scale atomic sample
- Tobias Bothwell ORCID:orcid.org/0000-0002-9532-12901,
- Colin J. Kennedy1 nAff2,
- Alexander Aeppli1,
- Dhruv Kedar ORCID:orcid.org/0000-0003-1117-86161,
- John M. Robinson1,
- Eric Oelker ORCID:orcid.org/0000-0002-3916-15951 nAff3,
- Alexander Staron1 &
- …
- Jun Ye ORCID:orcid.org/0000-0003-0076-21121
Naturevolume 602, pages420–424 (2022)Cite this article
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Abstract
Einstein’s theory of general relativity states that clocks at different gravitational potentials tick at different rates relative to lab coordinates—an effect known as the gravitational redshift1. As fundamental probes of space and time, atomic clocks have long served to test this prediction at distance scales from 30 centimetres to thousands of kilometres2,3,4. Ultimately, clocks will enable the study of the union of general relativity and quantum mechanics once they become sensitive to the finite wavefunction of quantum objects oscillating in curved space-time. Towards this regime, we measure a linear frequency gradient consistent with the gravitational redshift within a single millimetre-scale sample of ultracold strontium. Our result is enabled by improving the fractional frequency measurement uncertainty by more than a factor of 10, now reaching 7.6 × 10−21. This heralds a new regime of clock operation necessitating intra-sample corrections for gravitational perturbations.
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The experimental data are available from the corresponding authors upon reasonable request.
Code availability
The code used for the analysis is available from the corresponding authors upon reasonable request.
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Acknowledgements
We acknowledge funding support from the Defense Advanced Research Projects Agency, National Science Foundation QLCI OMA-2016244, the DOE Quantum System Accelerator, the National Institute of Standards and Technology, National Science Foundation Phys-1734006 and the Air Force Office for Scientific Research. We are grateful for theory insight from A. Chu, P. He and A. M. Rey. We acknowledge J. Zaris, J. Uhrich, J. Meyer, R. Hutson, C. Sanner, W. Milner, L. Sonderhouse, L. Yan, M. Miklos, Y. M. Tso and S. Kolkowitz for stimulating discussions and technical contributions. We thank J. Thompson, C. Regal, J. Hall and S. Haroche for careful reading of the manuscript.
Author information
Colin J. Kennedy
Present address: Quantinuum, Broomfield, CO, USA
Eric Oelker
Present address: Physics Department, University of Glasgow, Glasgow, UK
Authors and Affiliations
JILA, National Institute of Standards and Technology and University of Colorado, Department of Physics, University of Colorado, Boulder, CO, USA
Tobias Bothwell, Colin J. Kennedy, Alexander Aeppli, Dhruv Kedar, John M. Robinson, Eric Oelker, Alexander Staron & Jun Ye
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- Colin J. Kennedy
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All authors contributed to carrying out the experiments, interpreting the results and writing the manuscript.
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Correspondence toTobias Bothwell orJun Ye.
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Bothwell, T., Kennedy, C.J., Aeppli, A.et al. Resolving the gravitational redshift across a millimetre-scale atomic sample.Nature602, 420–424 (2022). https://doi.org/10.1038/s41586-021-04349-7
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