Speaker
Description
Mid-circuit measurement and readout (MCMR) are essential requirements for fault-tolerant trapped-ion quantum computers, as they enable syndrome measurement and feedback in quantum error correction protocols. Implementing these operations on auxiliary qubits in single-species trapped ion crystals remains challenging, as photon absorption due to resonance-fluorescence detection can introduce significant decoherence in nearby data qubits. In this work, we investigate a simplified MCMR architecture with trapped barium ions that utilises tightly focused, far off-resonant lasers combined with a global beam that couples to the $6S_{1/2} \rightarrow 5D_{3/2}$ transition at 2051 nm in Ba$^+$. We propose to mitigate decoherence in data qubits by implementing background-free detection of the auxiliary qubits with the 2051 nm laser, after which the auxiliary qubits can be cooled via mid-sequence sideband cooling with the same laser. To support stable operation, we perform frequency stabilisation of the 2051 nm laser via locking to an optical frequency comb. Ultimately, this work supports the implementation of MCMR and mid-sequence cooling in single-species quantum processors.
| Academic level | PhD student |
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