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.
@article{arxiv.1405.6117,
title = {Room-Temperature Quantum Memory for Polarization States},
author = {Connor Kupchak and Thomas Mittiga and Bertus Jordaan and Mehdi Namazi and Christian Nölleke and Eden Figueroa},
journal= {arXiv preprint arXiv:1405.6117},
year = {2014}
}