Quantum teleportation
As quantum teleportation the first time in 1997 conducted by Anton Zeilinger experiment with photons is called that transmits quantum states using an immediate (or instantaneous ) state change together entangled quantum systems.
The idea of quantum teleportation is by Asher Peres, William Wootters, Gilles Brassard, Charles H. Bennett, Richard Josza and Claude Crepeau in a paper published in Physical Review Letters in 1993. Quantum teleportation was first demonstrated about the same time with Anton Zeilinger experimentally by Sandu Popescu and others by quantum optical experiments.
To complete teleportation, so transmission of a quantum state additionally information between transmitter and receiver on a classic way has ( therefore with a maximum speed of light) to be replaced.
Experiments in 2004
In 2004 it succeeded in two working groups ( University of Innsbruck and NIST in Boulder, Colorado) for the first time, more precisely perform quantum teleportation with atoms with ions.
Also in 2004, succeeded in Vienna researchers led by Rupert Ursin and Anton Zeilinger for the first time outside the lab, a quantum state of a photon to teleport. You bridged a distance of 600 m below the Danube. For an optical fiber was transferred into a sewer under the Danube to ( the polarization ) to transmit the quantum state of about teleporting photon from the Danube Island (Alice, Alice and Bob) on the southern side of the Danube (Bob ) to another photon. At Alice the source of entangled photons was set up and transmit one of the entangled photons of the pair via a fiber optic cable to Bob. The other photon of the pair superimposed to Alice with the teleporting photon and made a Bell state measurement - while the original to be transmitted polarization state of Alice's photon was destroyed. The results of Alice's Bell state measurement that can distinguish two of the possible four Bell states from each other, were transmitted through a classical information channel to Bob, who then - if necessary - a corresponding unitary transformation ( a rotation of the polarization direction) applied them to be entangled photon to the transfer of the quantum state (ie, the original polarization direction of Alice's photon) conclude on this.
Progress made since the
In July 2009, researchers from the universities of Auckland ( New Zealand), Griffith University in Queensland (Australia) and Doha ( Qatar) proposed a method of how you can get a light beam or a complete quantum field, including the fluctuations over time teleport. This " strong" teleportation (including fluctuations) is considered to be a prerequisite for some quantum information applications and could lead to the teleportation of quantum images.
In May 2010, the science journal Nature reported on the successful quantum teleportation over a distance of 16 km in the field carried out by a Chinese team led by Xian -Min Jin. This has been achieved an average accuracy of 89 percent, which is significantly above classically expected limit of 2/3.
In May 2012, researchers at the Chinese University of Science and Technology claims to have overcome with the help of a laser, a distance of 97 kilometers, thus setting a new record.
In September 2012, the scientific journal Nature published a report on a quantum teleportation over a distance of 143 km from La Palma to Tenerife.
Practical significance
The practical importance of quantum teleportation is not about the fact that one could transport information or even articles so faster than light. In contrast, the quantum teleportation is therefore of practical importance, because it allows to transmit quantum states without altering simultaneously by a measurement process (compare: Quantum mechanical measurement). For a quantum computer so technically promising possibilities open for transmission, storage and processing of qubits.
The quantum teleportation does not allow to copy a quantum state. The teleported state after transmission on the sender side no longer be reconstructed, according to the no- cloning theorem.