  A neutral-atom system serves as a promising platform for realizing gate-based
quantum computing because of its capability to trap and control several atomic
qubits in different geometries and the ability to perform strong, long-range
interactions between qubits; however, the two-qubit entangling gate fidelity
lags behind competing platforms such as superconducting systems and trapped
ions. The aim of our work is to design a fast, robust, high-fidelity
controlled-Z (CZ) gate, based on the Rydberg-blockade mechanism, for neutral
atoms. We propose a gate procedure that relies on simultaneous and
transitionless quantum driving of a pair of atoms using broadband lasers. By
simulating a system of two interacting Caesium atoms, including spontaneous
emission from excited levels and parameter fluctuations, we yield a
Rydberg-blockade CZ gate with fidelity 0.9985 over an operation time of
$0.12~\mu$s. Our gate procedure delivers CZ gates that are superior than the
state-of-the-art experimental CZ gate and the simulated CZ gates based on
adiabatic driving of atoms. Our results show that our gate procedure carries
significant potential for achieving scalable quantum computing using neutral
atoms.
