Sub-ms, nondestructive, time-resolved quantum-state readout of a single, trapped neutral atom

TL;DR

This paper presents a rapid, nondestructive method for reading the quantum state of a single neutral atom with high fidelity, suitable for quantum computing and simulation applications.

Contribution

The authors demonstrate a sub-millisecond, nondestructive quantum-state readout technique for a single trapped neutral atom that is insensitive to magnetic sub-level populations.

Findings

Achieved 97.6% readout fidelity in 160 μs

Retained atom in over 97% of trials after readout

Method is insensitive to magnetic sub-level distribution

Abstract

We achieve fast, nondestructive quantum-state readout via fluorescence detection of a single $^{87}$Rb atom in the 5$S_{1/2}$ ($F=2$) ground state held in an optical dipole trap. The atom is driven by linearly-polarized readout laser beams, making the scheme insensitive to the distribution of atomic population in the magnetic sub-levels. We demonstrate a readout fidelity of $97.6\pm0.2\%$ in a readout time of $160\pm20$ $\mu$s with the atom retained in $>97\%$ of the trials, representing an advancement over other magnetic-state-insensitive techniques. We demonstrate that the $F=2$ state is partially protected from optical pumping by the distribution of the dipole matrix elements for the various transitions and the AC-Stark shifts from the optical trap. Our results are likely to find application in neutral-atom quantum computing and simulation.