Soft-controlled quantum gate with enhanced robustness and undegraded dynamics in Rydberg atoms

Rydberg atoms have exhibited excellent potentials to become a competent platform of implementing quantum computation, which demands to execute various quantum gates fast and faithfully. We propose a dynamic mechanism of two interacting Rydberg atoms for implementing a high-fidelity SWAP gate on ground-state manifolds, where the amplitude modulation and soft quantum control of lasers driving ground-Rydberg state transitions are elaborately matched with the interaction strength between atoms so as to engineer the desired transformation of atomic states. Compared with the recent Rydberg-atom SWAP gate scheme, the present one possesses the undegraded first-order dynamics and shows an interference-induced suppression of the doubly-excited Rydberg state, so it costs shorter gate time and exhibits greater robustness against atomic decay and deviations in the interatomic separation (interaction strengths). The present mechanism of implementing a SWAP gate on interacting Rydberg atoms could facilitate high-fidelity demonstrations of atomic ground state transformation and further exploitation of peculiar dynamics.