Storing polarization entangled qubits at a telecom wavelength in a cold rubidium atomic ensemble via a quantum interface
Résumé
Quantum communication aims at generating and distributing entangled pairs of photonic qubits (or flying qubits) at a telecom wavelength between distant sites, in order to implement quantum information protocols, such as quantum key distribution, quantum teleportation and quantum processing. For many quantum protocols, and especially for quantum repeaters, which make quantum communication over long distances much more efficient, storing of entangled states is necessary and represents a crucial step towards the realization of a real quantum network. A current outstanding challenge is thus to implement quantum memories for entangled qubits, carried by telecom photons, that combine high efficiency, long storage time and near-perfect fidelity between the input and output states. With this project, our goal is to merge the techniques of telecom wavelengths qubit distribution with quantum storage at shorter wavelength (typically for atomic transitions). Our idea is to map, via a quantum interface, polarization entangled qubits at a telecom wave- length onto a cold atomic ensemble, serving as a quantum memory device.