  Compared with the idea of universal quantum computation, a direct synthesis
of a multiqubit logic gate can greatly improve the efficiency of quantum
information processing tasks. Here we propose an efficient scheme to implement
a three-qubit controlled-not (Toffoli) gate of neutral atoms based on
unconventional Rydberg pumping. By adjusting the strengths of Rabi frequencies
of driving fields, the Toffoli gate can be achieved within one step, which is
also insensitive to the fluctuation of the Rydberg-Rydberg interaction.
Considering different atom alignments, we can obtain a high-fidelity Toffoli
gate at the same operation time $\sim 7~\mu s$. In addition, our scheme can be
further extended to the four-qubit case without altering the operating time.
