Heralded Storage of a Photonic Quantum Bit in a Single Atom

TL;DR

This paper demonstrates a robust method for storing and transferring photonic quantum bits in a single atom with high fidelity and efficiency, advancing quantum network technology.

Contribution

The authors introduce a heralded storage scheme for photonic qubits in a single atom that surpasses previous methods in efficiency and robustness against timing jitter.

Findings

Heralded transfer of polarization qubit with 39% efficiency and 86% fidelity

Reverse qubit transfer with 88% fidelity and up to 69% efficiency

Scheme is robust against photon arrival-time jitter

Abstract

Combining techniques of cavity quantum electrodynamics, quantum measurement, and quantum feedback, we have realized the heralded transfer of a polarization qubit from a photon onto a single atom with 39% efficiency and 86% fidelity. The reverse process, namely, qubit transfer from the atom onto a given photon, is demonstrated with 88% fidelity and an estimated efficiency of up to 69%. In contrast to previous work based on two-photon interference, our scheme is robust against photon arrival-time jitter and achieves much higher efficiencies. Thus, it constitutes a key step toward the implementation of a long-distance quantum network.