Fast high-fidelity single-qubit gates for flip-flop qubits in silicon

Understand

The flip-flop qubit, encoded in the states with antiparallel donor-bound electron and donor nuclear spins in silicon, showcases long coherence times, good controllability, and, in contrast to other donor-spin-based schemes, long-distance coupling.

• Electron spin control near the interface, however, is likely to shorten the relaxation time by many orders of magnitude, reducing the overall qubit quality factor.
• Here, we theoretically study the multilevel system that is formed by the interacting electron and nuclear spins and derive analytical effective two-level Hamiltonians with and without periodic driving.
• We then propose an optimal control scheme that produces fast and robust single-qubit gates in the presence of low-frequency noise without relying on parametrically restrictive sweet spots.