text: 103,7,1345161894189928448,1489278174,Claire Edmunds,"Starting off 2021 right with a new paper on arXiv from @ARC_EQUS and @Sydney_Science! Exciting new work reducing the measurement error in Yb 171 ions using electron shelving 1/5 #quantum #trappedions <LINK> Yb ions are awesome for #quantumcomputing as they store info for a long time and aren't too badly affected by magnetic field noise (both @honeywell @IonQ_Inc use Yb!) But measurement error tends to be larger as the qubit states can mix during detection(""off-resonant scattering"") By shelving the |1&gt; qubit state to a metastable D5/2 level before detection, we achieve single-qubit detection errors of 1.8e-3 on an APD (6x lower than our best efforts previously!) and 7.7e-3 on an EMCCD camera (4x lower) 3/5 We record a detection error as low as 6e-6 and 6.3e-4 on the APD and EMCCD if we shelve to the long-lived F7/2 state (a procedure that is currently shelving-rate limited) An amazing team effort with @MJBiercuk, Ting Rei Tan, Alistair Milne and Ashwin Singh, led by @CHQuant! 4/5 <LINK> This project goes hand in hand with a precision characterisation on the 411nm transition in Yb that we use for the electron shelving, up on arXiv a few days ago <LINK> <LINK> ping @Berkeley_ions @Ion_busters @IonQ_Inc @iqoqi @SandiaLabs",https://arxiv.org/abs/2012.14606,"Qubits encoded in hyperfine states of trapped ions are ideal for quantum computation given their long lifetimes and low sensitivity to magnetic fields, yet they suffer from off-resonant scattering during detection often limiting their measurement fidelity. In ${}^{171}$Yb$^{+}$ this is exacerbated by a low fluorescence yield, which leads to a need for complex and expensive hardware - a problematic bottleneck especially when scaling up the number of qubits. We demonstrate a detection routine based on electron shelving to address this issue in ${}^{171}$Yb$^{+}$ and achieve a 5.6$\times$ reduction in single-ion detection error on an avalanche photodiode to $1.8(2)\times10^{-3}$ in a 100 $\mu$s detection period, and a 4.3$\times$ error reduction on an electron multiplying CCD camera, with $7.7(2)\times10^{-3}$ error in 400 $\mu$s. We further improve the characterization of a repump transition at 760 nm to enable a more rapid reset of the auxiliary $^2$F$_{7/2}$ states populated after shelving. Finally, we examine the detection fidelity limit using the long-lived $^2$F$_{7/2}$ state, achieving a further 300$\times$ and 12$\times$ reduction in error to $6(7)\times10^{-6}$ and $6.3(3)\times10^{-4}$ in 1 ms on the respective detectors. While shelving-rate limited in our setup, we suggest various techniques to realize this detection method at speeds compatible with quantum information processing, providing a pathway to ultra-high fidelity detection in ${}^{171}$Yb$^{+}$. ","Scalable hyperfine qubit state detection via electron shelving in the