@article{12824,
  keywords = {General Physics and Astronomy},
  author = {Nathan Schine and Aaron Young and William Eckner and Michael Martin and Adam Kaufman},
  title = {Long-lived Bell states in an array of optical clock qubits},
  abstract = {The generation of long-lived entanglement in optical atomic clocks is one of the main goals of quantum metrology. Arrays of neutral atoms, where Rydberg-based interactions may generate entanglement between individually controlled and resolved atoms, constitute a promising quantum platform to achieve this. Here we leverage the programmable state preparation afforded by optical tweezers and the efficient strong confinement of a three-dimensional optical lattice to prepare an ensemble of strontium-atom pairs in their motional ground state. We engineer global single-qubit gates on the optical clock transition and two-qubit entangling gates via adiabatic Rydberg dressing, enabling the generation of Bell states with a state-preparation-and-measurement-corrected fidelity of 92.8(2.0)% (87.1(1.6)% without state-preparation-and-measurement correction). For use in quantum metrology, it is furthermore critical that the resulting entanglement be long lived; we find that the coherence of the Bell state has a lifetime of 4.2(6) s via parity correlations and simultaneous comparisons between entangled and unentangled ensembles. Such long-lived Bell states can be useful for enhancing metrological stability and bandwidth. In the future, atomic rearrangement will enable the implementation of many-qubit gates and cluster state generation, as well as explorations of the transverse field Ising model.},
  year = {2022},
  journal = {Nature Physics},
  volume = {18},
  pages = {1067},
  month = {2022-08},
  publisher = {Springer Science and Business Media LLC},
  issn = {1745-2473, 1745-2481},
  doi = {10.1038/s41567-022-01678-w},
}