Curated by RSF Research Staff
Earth-to-Satellite Quantum Teleportation Achieved
Last year Chinese researchers launched a satellite, named Micius---after an ancient Chinese philosopher of the 4th century B.C.E.---that contains a highly sensitive photon receiver that can detect single photons transmitted from Earth. If detection of single photons from up to 1400 kilometers away was not impressive enough, Micius has the capability to measure quantum states of the photons so that entanglement can be accomplished over record-breaking distances. Now the Chinese research team has used the Earth-to-satellite transfer of entangled photons to perform an information transmission technique known as quantum teleportation.
Although the name seems to imply a kind of instantaneous transmission of something from point A to point B, quantum teleportation doesn’t teleport large physical objects in the way that is commonly depicted in sci-fi, in this sense it’s not really teleportation at all. Unlike physical teleportation of matter through empty space—à la Star Trek—quantum teleportation is a way to transfer information by reconstructing an unknown quantum state without physically transporting the object itself.
Essentially, a quantum state (which must remain unobserved, and hence unknown) encoded on a photon, atom, or ion (quantum information), is transferred to one of a quantum entangled pair, where the original information can then be remotely reconstructed via the other partner of the entangled pair that has traveled some distance via a classical channel, ostensibly at any arbitrary distance. In practice, the main use of this technology will probably be to send quantum encrypted signals that can only be accessed by the receiver. In this way, quantum teleportation is a potential method to send ultra-secure encrypted information via quantum entanglement.
While the information that is teleported is in theory practically immune to interception by a third party, which would destroy the quantum state, the information must still be transmitted via classical channels – so it is not an instantaneous or superluminal transmission. Following the successful transmission of quantum entangled particle-pairs from ground to satellite, a natural next step would be to use the technique for the quantum teleportation of information, which eventually can be used to establish large-scale quantum networks and distributed quantum computation. The present feat of Earth-to-satellite teleportation may be the first step in a global-scale “quantum internet”.
In the report of a previous record quantum teleportation over 143 kilometers, researchers describe the potential of quantum teleportation --
The quantum internet is predicted to be the next-generation information processing platform, promising secure communication and an exponential speed-up in distributed computation. The distribution of single qubits over large distances via quantum teleportation is a key ingredient for realizing such a global platform. By using quantum teleportation, unknown quantum states can be transferred over arbitrary distances to a party whose location is unknown. Since the first experimental demonstrations of quantum teleportation of independent external qubits, an internal qubit and squeezed states, researchers have progressively extended the communication distance. – Zeilinger et al. 2012.