High Fidelity Universal Gate Set for 9Be+ Ion Qubits
John P. Gaebler, Ting Rei Tan, Yong Wan, Yiheng Lin, Ryan S. Bowler, Adam C. Keith, Scott C. Glancy, Kevin J. Coakley, Emanuel H. Knill, Dietrich G. Leibfried, David J. Wineland
We report high-fidelity laser-beam-induced quantum logic gates on qubits comprised of hyperfine states in 9Be+ ions, achieved in part through a combination of improved laser beam quality and control and improved state preparation. We demonstrate single-qubit gates with error per gate of 3.7(3) x 10-5. By creating a Bell state with a deterministic two-qubit gate, we deduce a gate infidelity of 8(4) x 10-4. We characterize the errors in our implementation and discuss methods to further reduce errors towards values that are compatible to fault-tolerant processing with realistic overhead.