Information losses in continuous-variable quantum teleportation
Holger Friedrich Hofmann, Toshiki Ide, Takayoshi Kobayashi, Akira Furusawa · Physical Review A · 2001
It is shown that the information losses due to the limited fidelity of continuous variable quantum teleportation are equivalent to the losses induced by a beam splitter of appropriate reflectivity. Quantum teleportation allows the transmission of an unknown quantum state by combining the nonlocal quantum coherence of entangled states with the transmission of classical information obtained in a joint measurement of the unknown input state and one part of the entangled pair [1]. Ideally, the classical information transmitted contains no information about the input state and the output state is exactly identical with the input state. However, this ideal form of quantum teleportation requires maximal entanglement. In continuous variable quantum teleportation [2–4], only non-maximal entanglement is available. As a consequence, the output state is not perfectly identical to the input state while the statistics of the joint measurement depend on the properties of the input state [5]. The classical information channel then carries information on the input state which may be extracted, e.g. in order to eavesdrop on a quantum communication channel [6]. The relationship between the