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Generating GHZ states with squeezing and post-selection



Byron Alexander, Hermann Uys, John Bollinger


Many quantum state preparation methods rely on a combination of dissipative quantum state initialization, followed by unitary evolution to a desired target state. Here we demonstrate the usefulness of quantum measurement as an additional tool for quantum state preparation. Starting from a pure separable multipartite state, a control sequence, which includes rotation, spin squeezing, quantum measurement and post-selection, generates a highly entangled multipartite state, which we refer to as Projected Squeezed states (or PS states). Through an optimization method, we then identify parameters required to maximize the overlap fidelity of the PS states with the maximally entangled Greenberger-Horne-Zeilinger states (or GHZ states). The method leads to an appreciable decrease in state preparation time of GHZ states when compared to preparation through unitary evolution only.
Physical Review A


GHZ states, post selection, quantum measurement, quantum sensing, quantum state preparation, spin squeezing, unitary evolution


Alexander, B. , Uys, H. and Bollinger, J. (2020), Generating GHZ states with squeezing and post-selection, Physical Review A, [online], (Accessed June 14, 2024)


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Created June 1, 2020, Updated October 12, 2021