@article{12097,
  author = {Martha Bodine and Jean-Daniel Deschênes and Isaac Khader and William Swann and Holly Leopardi and Kyle Beloy and Tobias Bothwell and Samuel Brewer and Sarah Bromley and Jwo-Sy Chen and Scott Diddams and Robert Fasano and Tara Fortier and David Hume and Dhruv Kedar and Colin Kennedy and Amanda Koepke and David Leibrandt and Andrew Ludlow and William McGrew and William Milner and Daniele Nicolodi and Eric Oelker and Thomas Parker and John Robinson and Jeffrey Sherman and Jian Yao and Jun Ye and Xiaogang Zhang and Nathan Newbury and Laura Sinclair},
  title = {Optical Atomic Clock Comparison through Turbulent Air},
  abstract = {We use frequency comb-based optical two-way time-frequency transfer (O-TWTFT) to measure the optical frequency ratio of state-of-the-art ytterbium and strontium optical atomic clocks separated by a 1.5 km open-air path. Our free-space measurement is compared to a simultaneous measurement acquired via a noise-cancelled fiber link. Despite non-stationary, ps-level time-of-flight variations in the free-space link, ratio measurements obtained from the two links, averaged over 30.5 hours across six days, agree to 6×10−19, showing that O-TWTFT can support free-space atomic clock comparisons below the 10−18 level.},
  year = {2020},
  journal = {Physical Review Research},
  volume = {2},
  chapter = {033395},
  pages = {033395},
  month = {2020-09},
  url = {https://journals.aps.org/prresearch/abstract/10.1103/PhysRevResearch.2.033395},
  doi = {10.1103/PhysRevResearch.2.033395},
}