We propose a new microwave gate which uses the intrinsic J-coupling of ions in a static magnetic gradient. The gate is virtually insensitive to common amplitude noise of the microwave fields and enables high fidelities despite qubit frequency fluctuations, while the J-coupling interaction’s inherent robustness to motional decoherence is retained. Errors far below the fault-tolerant threshold can be achieved at high initial temperatures, negating the requirement of sideband cooling below the Doppler temperature.
Manuscript : Robust Entanglement by Continuous Dynamical Decoupling of the J-Coupling Interaction
