Quantum information processors promise fast algorithms for problems inaccessible to classical computers. But since qubits are noisy and error-prone, they will depend on fault-tolerant quantum error correction (FTQEC) to compute reliably. Quantum error correction can protect against general noise if - and only if - the error in each physical qubit operation is smaller than a certain threshold. The threshold for general errors is quantified by their diamond norm. Until now, qubits have been assessed primarily by randomized benchmarking, which reports a different error rate that is not sensitive to all errors, and cannot be compared directly to diamond norm thresholds. Here we use gate set tomography to completely characterize operations on a trapped-Yb+-ion qubit and demonstrate with greater than 95% confidence that they satisfy a rigorous threshold for FTQEC (diamond norm ≤6.7 × 10-4).
The Frequency Translation to Demonstrate a Hybrid Quantum Architecture project focused on developing nonlinear optics to couple two different ion species and make their emitted UV photons indistinguishable. Successful demonstration of photonic coupling of different ion species lays the foundation for coupling drastically different types of qubits, such as ions and quantum dots. Frequency conversion of single photons emitted from single ions remains a "hot" topic with many groups pursing this effort; however due to challenges in producing short period periodically poled crystal it has yet to be realized. This report details the efforts of trying to frequency convert single photons emitted from trapped ions to other wavelengths. We present our theoretical studies of candidate platforms for frequency conversion: photonic crystal fibers, X(2) nonlinear crystals in optical cavities, and photonic crystal cavities. We also present experiment results in ion trapping X(2) nonlinear crystals measurements and photonic crystal fabrication
We will present results of the design, operation, and performance of surface ion micro-traps fabricated at Sandia. Recent progress in the testing of the micro-traps will be highlighted, including successful motional control of ions and the validation of simulations with experiments.