Lossless State Detection of Single Neutral Atoms

TL;DR

This paper presents a method for lossless, high-fidelity state detection of single neutral atoms using cavity-enhanced fluorescence, enabling repeated, non-destructive measurements with robustness against frequency shifts.

Contribution

The authors demonstrate a novel, lossless state detection technique for neutral atoms that does not require strong coupling and is applicable to various quantum systems.

Findings

Achieved 99.4% fidelity in 85 microseconds

Enabled hundreds of non-destructive measurements per atom

Robust against atomic frequency shifts

Abstract

We introduce lossless state detection of trapped neutral atoms based on cavity-enhanced fluorescence. In an experiment with a single 87-Rb atom, a hyperfine-state-detection fidelity of 99.4% is achieved in 85 microseconds. The quantum bit is interrogated many hundreds of times without loss of the atom while a result is obtained in every readout attempt. The fidelity proves robust against atomic frequency shifts induced by the trapping potential. Our scheme does not require strong coupling between the atom and cavity and can be generalized to other systems with an optically accessible quantum bit.