Gaussian soft control-based quantum fan-out gate in ground-state manifolds of neutral atoms

We propose a reliable scheme for one-step synthesizing of a quantum fan-out gate in a system of neutral atoms. By introducing the off-resonant driving fields with Gaussian temporal modulation, the dynamics of the system is strictly restricted to the ground-state subspace on the basis of unconventional Rydberg pumping, which exhibits more robustness than the constant driving method against the fluctuation of system parameters, such as operating time and environment noise. As a direct application of this quantum fan-out gate, we discuss in detail the preparation of multipartite Greenberger–Horne–Zeilinger (GHZ) state for neutral atoms. The result shows that a high fidelity better than 99% can be obtained within the state-of-the-art experiments.