A team of researchers from the Massachusetts Institute of Technology and Northwestern University is developing a system for achieving long-distance, high-fidelity teleportation and long-duration quantum storage. This paper will report recent progress that has been made in architectural studies, entanglement sources, and quantum memory.
A recent proposal for realizing long-distance, high-fidelity qubit teleportation is reviewed. This quantum communication architecture relies on an ultrabright source of polarization-entangled photons plus a pair of trapped-atom quantum memories, and it is compatible with long-distance transmission over standard telecommunication fiber. Models are developed for assessing the effects of amplitude, phase, and frequency errors in the entanglement source, as well as fiber loss and imperfect polarization restoration, on the throughput and fidelity of the system.
The ability to distribute quantum resources over long distances is a key \nelement for the development of several practical applications in the field of \nquantum information. In this way, major efforts have been made in the \npast decade to extend the maximum distances for the observation of entanglement \nor for the realization of quantum cryptography. Using optical fibers \nas the quantum channel, entanglement has already been achieved between \nphotons separated by 50 km of fiber, and quantum cryptography is now a \ncommercial technology that allows quantum key distributon over distances \nup to around 100 km. Progress has also been made towards entanglement \ndistribution in free space, with the achieved distances of about 10 km \non ground atmosphere being a substantial step toward the development \nof satellite-based quantum communication.