Ultra-low-noise room-temperature quantum memory for polarization qubits

TL;DR

This paper demonstrates a room-temperature quantum memory with ultra-low noise and high fidelity for polarization qubits, surpassing classical limits and showing promise for practical quantum information processing.

Contribution

It introduces a simple, room-temperature quantum memory achieving fidelities over 90%, surpassing classical strategies, with novel techniques to approach near-unity fidelity.

Findings

Fidelities >90% for single-photon polarization qubits

Surpassed classical memory efficiency thresholds

Demonstrated potential for practical room-temperature quantum devices

Abstract

Here we show an ultra-low noise regime of operation in a simple quantum memory in warm Rb atomic vapor. By modelling the quantum dynamics of four-level room temperature atoms, we achieve fidelities >90% for single-photon level polarization qubits, clearly surpassing any classical strategy exploiting the non-unitary memory efficiency. This is the first time such important threshold has been crossed with a room temperature device. Additionally we also show novel experimental techniques capable of producing fidelities close to unity. Our results demonstrate the potential of simple, resource-moderate experimental room temperature quantum devices.