Room-Temperature Quantum Memory for Polarization States

TL;DR

This paper demonstrates a room-temperature quantum memory capable of storing polarization qubits with high fidelity and low background noise, advancing atomic vapor systems towards practical quantum information processing.

Contribution

It introduces a room-temperature quantum memory using a vapor cell that surpasses classical fidelity limits for polarization qubits.

Findings

Achieved fidelity surpassing classical limits for weak laser pulses.

Maintained a signal-to-background ratio higher than 1.

Proved vapor cells can operate with low background noise for quantum memory.

Abstract

An optical quantum memory is a stationary device that is capable of storing and recreating photonic qubits with a higher fidelity than any classical device. Thus far, these two requirements have been fulfilled in systems based on cold atoms and cryogenically cooled crystals. Here, we report a room-temperature quantum memory capable of storing arbitrary polarization qubits with a signal-to-background ratio higher than 1 and an average fidelity clearly surpassing the classical limit for weak laser pulses containing 1.6 photons on average. Our results prove that a common vapor cell can reach the low background noise levels necessary for quantum memory operation, and propels atomic-vapor systems to a level of quantum functionality akin to other quantum information processing architectures.