High-Fidelity Simultaneous Detection of Trapped Ion Qubit Register.

Qubit state detection is an important part of quantum computation. As number of qubits in a quantum register increases, it is necessary to maintain high fidelity detection to accurately measure the multi-qubit state. Here we present experimental demonstration of high-fidelity detection of a multi-qubit trapped ion register with single qubit detection fidelity of 0.99995(+3/-8) and 4-qubit state detection fidelity of 0.9991(+5/-15) using a novel single-photon-sensitive camera with fast data collection, excellent temporal and spatial resolution, and low instrumental crosstalk.