Non-destructive mid-circuit measurements on a neutral atom quantum processor

Quantum bits are sensitive to the external environment and have a limited coherence time. Quantum error correction can mitigate this degradation by combining mid-circuit measurements of ancilla qubits with corrective operations that are conditioned on the results of measurement outcomes. However, conventional state measurement protocols for neutral atom qubits in an optical lattice are not compatible with mid-circuit measurement since they are global and destructive.



We present mid-circuit measurement in array of single species neutral atoms based on shelving data qubits in a hyperfine level that is dark to the readout light. After shelving the data qubits we use hyperfine state-selective fluorescence to measure an ancilla qubit. We implement this approach on a 2D array of Cs atoms and characterize the readout fidelity of an ancilla qubit and the error that the readout induces on the data qubits. We will present progress towards implementation of quantum algorithms which leverage mid-circuit measurement and feedforward in place of multi-qubit entangling gates. We present methods for recooling and resetting ancilla qubits and prospects for full error correction.