Quantum Storage of Photonic Entanglement in a Crystal

Abstract

Entanglement is the fundamental characteristic of quantum physics. Large experimental efforts are devoted to harness entanglement between various physical systems. In particular, entanglement between light and material systems is interesting due to their prospective roles as "flying" and stationary qubits in future quantum information technologies, such as quantum repeaters and quantum networks. Here we report the first demonstration of entanglement between a photon at telecommunication wavelength and a single collective atomic excitation stored in a crystal. One photon from an energy-time entangled pair is mapped onto a crystal and then released into a well-defined spatial mode after a predetermined storage time. The other photon is at telecommunication wavelength and is sent directly through a 50 m fiber link to an analyzer. Successful transfer of entanglement to the crystal and back is proven by a violation of the Clauser-Horne-Shimony-Holt (CHSH) inequality by almost three standard deviations (S=2.64+/-0.23). These results represent an important step towards quantum communication technologies based on solid-state devices. In particular, our resources pave the way for building efficient multiplexed quantum repeaters for long-distance quantum networks.

5 pages, 3 figures + supplementary information; fixed typo in ref. [36]

References in corpus (7)

• The Quantum Internet
• Quantum teleportation between light and matter
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• Multimode Memories in Atomic Ensembles
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Cited by in corpus (7)

• A Single-Atom Quantum Memory
• A Quantum Pulse Gate based on Spectrally Engineered Sum Frequency Generation
• Highly multimode memory in a crystal
• Remote Entanglement between a Single Atom and a Bose-Einstein Condensate
• Approaches for a quantum memory at telecommunication wavelengths
• High speed spatially multimode atomic memory
• Sub-nanosecond Electro-optic Modulation of Triggered Single Photons from a Quantum Dot