One-step achievement of robust multipartite Greenberger-Horne-Zeilinger state and controlled-phase gate via Rydberg interaction

We present a proposal for generation of a robust tripartite Greenberger-Horne-Zeilinger state among three individual neutral Rydberg atoms. By modulating the relation between two-photon detuning and Rydberg interaction strength U-ij (r), an effective Raman coupling is obtained between the hyperfine ground states vertical bar F = 2, M = 2 > of three Rb-87 atoms and the Rydberg states vertical bar rrr > via the third-order perturbation theory. This method is also capable of implementing a three-qubit controlled-phase gate with each qubit encoded into the hyperfine ground states vertical bar F = 1, M = 1 > and vertical bar F = 2, M = 2 >. As an extension, we generalize our scheme to the case of the multipartite GHZ state and quantum gate in virtue of high-order perturbation theory. (C) 2014 Optical Society of America