Fast, Robust and Laser-Free Universal Entangling Gates for Trapped-Ion Quantum Computing

A novel two-qubit entangling gate for RF-controlled trapped-ion quantumprocessors is proposed theoretically and demonstrated experimentally. The speedof this gate is an order of magnitude higher than that of previouslydemonstrated two-qubit entangling gates in static magnetic field gradients. Atthe same time, the phase-modulated field driving the gate, dynamicallydecouples the qubits from amplitude and frequency noise, increasing the qubits'coherence time by two orders of magnitude. The gate requires only a singlecontinuous RF field per qubit, making it well suited for scaling a quantumprocessor to large numbers of qubits. Implementing this entangling gate, wegenerate the Bell states |Φ^+⟩ and |Ψ^+⟩ in ≤ 313μs with fidelities up to 98^+2_-3 magnetic gradient of only 19.09 T/m. At higher magnetic field gradients, theentangling gate speed can be further improved to match that of laser-basedcounterparts.