Real-time capable CCD-based individual trapped-ion qubit measurement

We report on the individual detection of ⁹Be⁺ qubit states undergoing coherent excitation using an EMCCD camera. The ions are trapped in a cryogenic surface-electrode ion trap with integrated microwave conductors [1] for near-field quantum control. This kind of trap promises good scalability to a higher number of qubits [2]. Together with the individual real-time detection this is a key requirement for many-body quantum simulation and also error-correction protocols in quantum information processing [3]. We discuss known error sources during state preparation and measurement in the order of 0.5% and comment on the sources and the amount of crosstalk in our detection system. We briefly present the used imaging system and compare the qubit state detection performance of the EMCCD camera with a PMT.

[1] Dubielzig et. al.,  Rev. Sci. Instr. 92, 043201 (2021)

[2] Kielpinski et. al., Nature 417, 709 (2002)

[3] Nielsen and Chuang, Quantum Computation and Quantum Information, Cambridge (2000)