Rabi-Robustness Multiqubit Geometric Gate with Rydberg Atoms

Due to the limitation of quantum resources, direct synthesis of a multiqubit logic gate can significantly improve the efficiency of practical quantum information processing. In this article, an enhanced-robustness gate scheme is proposed to implement three-qubit controlled gates, i.e., $C_{2}U$ and ${\mathrm{CU}}_2$, by using resonant dipole–dipole exchange interaction-induced adiabatic evolutions along with the dark state dynamics and super-robust pulse sequences in Rydberg atoms. Such a gate scheme can execute arbitrary single-qubit operations on the target qubit with pure geometric phase and is especially suitable for the case where the decoherence is not very obvious. Taking $C_2\mathrm{NOT}$ and ${\mathrm{CNOT}}_2$ as typical examples, various experimental imperfections are studied, including the Doppler effect, spontaneous emission of the intermediate state, laser phase noise, and fluctuations of interaction and external fields. Therefore, with the increasing demand for multiqubit gates, the proposal provides a more promising alternative for future fault-tolerant and scalable quantum computation.