Experimental quantum teleportation of propagating microwaves

The field of experimental quantum communication promises ways of efficient and unconditional secure information exchange in quantum states. The possibility of transferring quantum information forms a cornerstone of the emerging field of quantum communication and quantum computation. Recent breakthroughs in quantum computation with superconducting circuits trigger a demand for quantum communication channels between superconducting processors separated in space at microwave length frequencies. To pursue this goal, Kirill G. Fedorov, and a team of scientists in Germany, Finland and Japan demonstrated unconditional quantum teleportation to propagate coherent microwave states by exploring two-mode squeezing and analog feedforward across a distance of 0.42 m. The researchers achieved a teleportation fidelity of F= 0.689±0.004, which exceeded the asymptotic no-cloning threshold, preventing the use of classical error correction methods on quantum states. The quantum state of the teleported state was preserved to open the avenue towards unconditional security in microwave quantum communication.