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@article{ef-21-2,
  title = {Resolving the gravitational redshift across a millimetre-scale atomic sample},
  author = {Bothwell, Tobias and Kennedy, Colin J. and Aeppli, Alexander and Kedar, Dhruv and Robinson, John M. and Oelker, Eric and Staron, Alexander and Ye, Jun},
  journal = {Nature},
  year = {2022},
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@article{ef-21-3,
  title = {Frequency ratio measurements at 18-digit accuracy using an optical clock network},
  author = {Boulder Atomic Clock Optical Network (BACON) Collaboration*,  and Beloy, Kyle and Bodine, Martha I. and Bothwell, Tobias and Brewer, Samuel M. and Bromley, Sarah L. and Chen, Jwo-Sy and Deschênes, Jean-Daniel and Diddams, Scott A. and Fasano, Robert J. and Fortier, Tara M. and Hassan, Youssef S. and Hume, David B. and Kedar, Dhruv and Kennedy, Colin J. and Khader, Isaac and Koepke, Amanda and Leibrandt, David R. and Leopardi, Holly and Ludlow, Andrew D. and McGrew, William F. and Milner, William R. and Newbury, Nathan R. and Nicolodi, Daniele and Oelker, Eric and Parker, Thomas E. and Robinson, John M. and Romisch, Stefania and Schäffer, Stefan A. and Sherman, Jeffrey A. and Sinclair, Laura C. and Sonderhouse, Lindsay and Swann, William C. and Yao, Jian and Ye, Jun and Zhang, Xiaogang},
  journal = {Nature},
  year = {2021},
  doi = {10.1038/s41586-021-03253-4},
  url = {https://doi.org/10.1038/s41586-021-03253-4}
}