Creation of 2000-atom Greenberger-Horne-Zeilinger states by entanglement amplification

Yajuan Zhao, Rui Zhang, Wenlan Chen, Xiang-Bin Wang, Jiazhong Hu

Published 2019-11-04Version 1

We propose a novel entanglement-creation scheme in a multi-atom ensemble, named entanglement amplification, which converts unentangled states into entangled states and amplifies less-entangled ones to maximally-entangled Greenberger-Horne-Zeilinger (GHZ) states. By shifting the energy of a particular Dicke state, we break the Hilbert space of the ensemble into two isolated subspaces to tear the coherent spin state into two components. Afterward, we can utilize the isolated spaces to further enhance the entanglement by coherently separating the two components. By one-particle Rabi drivings on atoms in a high-finesse optical cavity illuminated by a single-frequency light, 2000-atom GHZ states can be created with a fidelity above 80% in an experimentally achievable system, making resources of ensembles at Heisenberg-limit practically available for quantum metrology.