Secure Quantum Teleportation Can Be Achieved Using Einstein's "Spooky" Steering

Monday, 14 December 2015 - 1:04PM
Physics
Monday, 14 December 2015 - 1:04PM
Secure Quantum Teleportation Can Be Achieved Using Einstein's "Spooky" Steering
It's unclear whether scientists will ever be able to achieve teleportation in the "beam me up, Scotty" sense, in which physical matter is dematerialized and rematerialized in a different location instantaneously. But quantum teleportation, or the instantaneous transport of quantum information, has been achieved, and it may be a viable form of communication in the near future. In a new study published in Physical Review Letters, a group of researchers has discovered a mechanism predicted by Einstein, called "quantum steering," that may make quantum teleportation completely secure.

Quantum teleportation involves the transport of quantum information, such as the exact state of a photon or electron, without moving the actual particle. In order to achieve this, an entangled state must be shared between the source and destination locations, often referred to as "Alice" and "Bob," creating a "quantum channel" between the two sites.
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"Teleportation works like a sophisticated fax machine, where a quantum state is transported from one location to another," said co-author Margaret Reid, from Swinburne University of Technology, in a statement. "Let's say 'Alice' begins the process by performing operations on the quantum state – something that encodes the state of a system – at her station. Based on the outcomes of her operations, she communicates (by telephone or public Internet) to 'Bob' at a distant location, who is then able to create a replica of the quantum state."
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Scientists first achieved quantum teleportation last year, and have been improving the process ever since, but they still haven't managed to send a message that didn't come out garbled and incoherent on the other side.

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"The problem is that unless special requirements are satisfied, quantum mechanics demands that the state at Bob's end will be 'fuzzed up'," said Reid.
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These "special requirements" involve a special kind of quantum entanglement called Einstein-Podolsky-Rosen steering, a theory based on Einstein and Schrodinger's "quantum steering," which states that a measurement has an immediate impact on another quantum state. Using this theory, the quality of the transported state could potentially be "perfect," allowing for messages to come through clearly and securely.

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"The beauty is that quantum mechanics guarantees that a perfect state can only be transported to one receiver," said Reid. "Any second 'eavesdropper' will get a fuzzy version."
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Via Science Alert.
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