Site-selective cavity readout and classical error correction of a 5-bit atomic register

TL;DR

This paper demonstrates site-selective cavity readout and classical error correction in a 10-site atomic array, achieving high fidelity and extended logical memory through adaptive strategies and repeated error correction rounds.

Contribution

It introduces a method for site-selective hyperfine-state cavity readout using Stark shifts and implements classical error correction to significantly improve atomic register reliability.

Findings

Achieved state discrimination fidelity of 0.994 for single atoms

Demonstrated adaptive search strategies for faster array readout

Extended logical memory fivefold beyond single-bit lifetime

Abstract

Optical cavities can provide fast and non-destructive readout of individual atomic qubits; however, scaling up to many qubits remains a challenge. Using locally addressed excited-state Stark shifts to tune atoms out of resonance, we realize site-selective hyperfine-state cavity readout across a 10-site array. The state discrimination fidelity is 0.994(1) for one atom and 0.989(2) averaged over the entire array at a survival probability of 0.975(1). To further speed up array readout, we demonstrate adaptive search strategies utilizing global/subset checks. Finally, we demonstrate repeated rounds of classical error correction, showing exponential suppression of logical error and extending logical memory fivefold beyond the single-bit idling lifetime.