Coming Soon: Quantum Cryptography at 3D

Coming Soon: Quantum Cryptography at 3D

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Quantum entanglement is one of the weird properties of quantum mechanics. Two particles, once joined, behave in a mirror-opposite way even when separated by great distances. Researchers at the University of Vienna and the Universitat Autonoma de Barcelona added a new twist to the strange phenomena, by entangling three photons and adding a 3D corkscrew motion. This should allow multiple recipients to receive information encoded in one transmission.

Entangling photons in a particular spin state and encoding them with information is a technique of quantum cryptography. This ensures that data is transmitted to its destination without interference, interception, or any change whatsoever, However, the amount of data this technique allows to transmit is quite limited.

In the usual two-dimensional entanglement, a photon exists in all spin states at once. When passed through a polarising filter, the photon can be set in one of four spin states – vertical, horizontal, left, right. The entangled particle mirrors the spin state perfectly. If one spins right, the other left.

In this research, the team managed to add another state to two of the three entangled photons – a corkscrew motion in opposite directions. “This type of asymmetric quantum entanglement has been predicted before on paper, but we are the first to actually create it in the lab,” said lead researcher Dr Mehul Malik from the University of Vienna.

What this allows is to encode different layers of information with one entangled structure, so multiple recipients can receive the information, while securely separated from one another.

It will be a few years before this research bears practical fruits. But once application is streamlined and widespread, it should allow for far more secure communications.

“The experiment opens the door for a future quantum Internet with more than two partners and it allows them to communicate more than one bit per photon,” said Anton Zeilinger, a quantum physicist at the the University of Vienna.