Entangled optical clocks via Rydberg blockade

We present an analysis of a protocol for creating fully entangled GHZ-type states of 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 [1]. We specifically analyze the realization of this scheme based on neutral Yb atoms.\\[4pt] [1] Komar et al, Nature Physics 10, 582-587 (2014)