By October 2006, a research team from the HFNL, USTC had successfully achieved for the first time the quantum teleportation of a two-qubit composite system as well as the manipulation of a six-photon entangled state.
The research group led by Prof．PAN Jianwei developed a unique six-photon interferometer in the experiment, which transferred the combined polarization state of two photons with the remaining four photons serving as a polarized "teleporter." Once reported as the cover story of Nature Physics, their work was highly appraised by its reviewer as being "bring large-scale quantum communication and computation a step closer."
By transferring the state of a quantttm system from one location to another, quantum teleportation is essential to quantum communication and plays a key role in many quantum computation protocols. Although experimental advances had been made before in the teleportation of single qubits, large scale applications require the transfer of composite systems containing two or more qubits.
Experimental quantum teleportation of a two-qubit composite system
Nature Physics 2, 678 - 682 (2006) doi:10.1038/nphys417
Quantum teleportation, a way to transfer the state of a quantum system from one location to another, is central to quantum communication and plays an important role in a number of quantum computation protocols. Previous experimental demonstrations have been implemented with single photonic or ionic qubits. However, teleportation of single qubits is insufficient for a large-scale realization of quantum communication and computation. Here, we present the experimental realization of quantum teleportation of a two-qubit composite system. In the experiment, we develop and exploit a six-photon interferometer to teleport an arbitrary polarization state of two photons. The observed teleportation fidelities for different initial states are all well beyond the state estimation limit of 0.40 for a two-qubit system. Not only does our six-photon interferometer provide an important step towards teleportation of a complex system, it will also enable future experimental investigations on a number of fundamental quantum communication and computation protocols.
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