‘Teleport’ images across the network securely using only light

High-dimensional quantum transport enabled by nonlinear detection. In our concept, information is encoded in a coherent source and overlaps a photon from an entangled pair in a nonlinear crystal for up -conversion by sum frequency generation, the latter acting as nonlinear. spatial mode detector. A bright source is required to achieve the efficiency required for nonlinear detection. Information and photons flow in opposite directions: one of Bob’s linked photons is sent to Alice and contains no information, while a measure of the other simultaneously with the transformed photon establishes the transport of information across the quantum link. Alice does not need to know this information for the process to work, while nonlinearity allows the state to be arbitrary and of unknown dimension and basis. Credit: Communication in Nature (2023). DOI: 10.1038/s41467-023-43949-x

Communication in Nature published research by an international team from Wits and ICFO- The Institute of Photonic Sciences, which shows the teleportation-like transport of “patterns” of light this is the first method that can transport images in a network without sending the image is an important step. towards the realization of a quantum network for high-dimensional entangled states.

Quantum communication over long distances is important for information security and is demonstrated by two-dimensional states (qubits) at great distances between satellites. This seems sufficient if we compare it to its classical counterpart, ie, sending bits that can be encoded in 1s (signal) and 0s (no signal), at the same time.

However, quantum optics allows us to add the alphabet and safely describe more complex systems in one shot, such as a unique fingerprint or a face.

“Traditionally, two communicating parties physically send information from one to the other, even in the quantum realm,” said Prof. Andrew Forbes, the lead PI from Wits University.

“Now, it’s possible to teleport information so it doesn’t physically travel across the nexus of ‘Star Trek’ technology made real.” Unfortunately, teleportation has so far only been demonstrated with three-dimensional states (imagine a three-pixel image), thus requiring more entangled photons to reach higher dimensions.

In this research, the team performed the first experimental demonstration of quantum transport in high-dimensional states with only two entangled photons as a quantum resource, resulting in information that appears to be “teleported.” ” from the sender to the receiver. To make the breakthrough, the team used a nonlinear optical detector that avoids the need for additional photons to be applied to any “pattern” that needs to be transmitted.

They report a new state-of-the-art of 15 dimensions, whose design can be scaled to even higher dimensions, paving the way for quantum connections. network with high information capacity.

Practical applications in a banking setting

Consider a customer who wants to send sensitive information in a fingerprint to the bank, perhaps. In traditional quantum communication, information must be physically sent from the customer to the bank, always with the risk of interception (even if it is secure). In the newly proposed quantum transport scheme, the bank sends a photon (one of an entangled pair) without information to the customer, who overlaps it with the nonlinear detector with the information to be sent.

As a result, the information appears in the bank exactly as if it was teleported there. No information is physically sent between the two parties, so the interception is fruitless, while the quantum link connecting the parties is established by the exchange of quantum entangled photons.

“This protocol has all the hallmarks of teleportation except for one important component: it requires a bright laser beam to make the nonlinear detector efficient so that the sender knows what to send, but does not need to know an,” explained Forbes. .

“In this sense, it is not strictly teleportation, but it can be done in the future if the nonlinear detector can be made more efficient.” Even as it stands now, it opens a new path for connecting quantum networks, bringing nonlinear quantum optics as a resource.

“We hope that this experiment that shows the feasibility of the process encourages further development in the nonlinear optics community by pushing the limits to a full quantum implementation,” said Dr. Adam Valls from ICFO (Barcelona), one of the project leaders who worked on the experiment during his postdoctoral fellowship at Wits.

“We have to be careful now, because this configuration doesn’t prevent a rogue sender from keeping better copies of the information to teleport, which means we could end up with more clones of Mr. Spock in the world of Star Trek if that’s what Scotty says. want.”

“From a practical point of view, the configuration we have shown now can be used to build a high-dimensional secure channel for quantum communication between two parties, as long as the protocol does not need to be fed- on a photon, as is the case for quantum repeaters.”

The recognition of Ph.D. RESEARCH REVEALS

Valls added, “Performing such proof-of-concept experiments with the technology available today has been an interesting journey, and we have Dr. Bereneice Sephton from Wits to thank for her determination and comprehensive expertise which is necessary to tame such an experimental animal. a true laboratory effort for which he should be commended.”

Forbes echoed the sentiment, “This was a heroic experiment, and Dr. Bereneice Sephton should be recognized because she was the one who made the system work and conducted the important experiments.”

The team plans to continue working in this direction, with the next step focusing on quantum transport in an optical fiber network.

More information:
Bereneice Sephton et al, Quantum transport of high-dimensional spatial information with nonlinear detectors, Communication in Nature (2023). DOI: 10.1038/s41467-023-43949-x

Provided by Wits University

Citation: ‘Teleporting’ images across networks safely using only light (2023, December 18) retrieved on December 22, 2023 from https://phys.org/news/2023-12-teleporting-images- network.html

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