We propose a protocol for creating a fully entangled GHZ-type state of neutral atoms in spatially separated optical atomic clocks. In our scheme, local operations make use of the strong dipole-dipole interaction between Rydberg excitations, which give rise to fast and reliable quantum operations involving all atoms in the ensemble. The necessary entanglement between distant ensembles is mediated by single-photon quantum channels and collectively enhanced light-matter couplings. These techniques can be used to create the recently proposed quantum clock network based on neutral atom optical clocks. We specifically analyze a possible realization of this scheme using neutral Yb ensembles.
@article{arxiv.1603.06258,
title = {Quantum network of neutral atom clocks},
author = {P. Kómár and T. Topcu and E. M. Kessler and A. Derevianko and V. Vuletić and J. Ye and M. D. Lukin},
journal= {arXiv preprint arXiv:1603.06258},
year = {2016}
}