Experimental quantum teleportation of propagating microwaves

Recent breakthroughs in quantum computation with superconducting circuits trigger a demand for quantum communication channels between spatially separated superconducting processors operating at microwave frequencies. An international team of researchers (Germany, Austria) demonstrated the unconditional quantum teleportation of propagating coherent microwave states by exploiting two-mode squeezing and analog feedforward over a macroscopic distance of d = 0.42 m. They achieved a teleportation fidelity of F = 0.689 ± 0.004, exceeding the asymptotic no-cloning threshold. Thus, the quantum nature of the teleported states is preserved, opening the avenue toward unconditional security in microwave quantum communication. As their principal teleportation resource, the team used a pair of entangled photons; to affect the teleportation, they initiated a measurement involving one photon of the pair and a third photon. As a consequence of this interaction, the state of polarization of the third photon was transferred perfectly to the second photon of the entangled pair. In principle, this process should work even if the teleportation takes place over an arbitrarily large distance…read more. TECHNICAL ARTICLE    Open Access 1 ,  2