1. Niels Bohr Institute, Copenhagen University, Blegdamsvej 17, Copenhagen Ø, Denmark
2. Max Planck Institute for Quantum Optics, Hans-Kopfermann-Str. 1, Garching, D-85748, Germany
3. Department of Physics and Astronomy, University of Aarhus, Aarhus, 8000, Denmark

Correspondence to: Eugene S. Polzik¹ Correspondence and requests for materials should be addressed to E.S.P. (Email: polzik@nbi.dk).

Abstract

Quantum teleportation¹ is an important ingredient in distributed quantum networks², and can also serve as an elementary operation in quantum computers³. Teleportation was first demonstrated as a transfer of a quantum state of light onto another light beam^{4, 5, 6}; later developments used optical relays⁷ and demonstrated entanglement swapping for continuous variables⁸. The teleportation of a quantum state between two single material particles (trapped ions) has now also been achieved^{9, 10}. Here we demonstrate teleportation between objects of a different nature—light and matter, which respectively represent 'flying' and 'stationary' media. A quantum state encoded in a light pulse is teleported onto a macroscopic object (an atomic ensemble containing 10¹² caesium atoms). Deterministic teleportation is achieved for sets of coherent states with mean photon number (n) up to a few hundred. The fidelities are 0.58 0.02 for n = 20 and 0.60 0.02 for n = 5—higher than any classical state transfer can possibly achieve¹¹. Besides being of fundamental interest, teleportation using a macroscopic atomic ensemble is relevant for the practical implementation of a quantum repeater². An important factor for the implementation of quantum networks is the teleportation distance between transmitter and receiver; this is 0.5 metres in the present experiment. As our experiment uses propagating light to achieve the entanglement of light and atoms required for teleportation, the present approach should be scalable to longer distances.

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