Quantum Communication: Beyond Classical Limits
Quantum communication has long been recognized for its potential in enhancing information security, especially over long distances. Achievements in this field, such as the demonstrated transmission of two-dimensional states (qubits) between satellites, already surpass the capabilities of classical bit-based communication.

However, the recent study by Prof. Andrew Forbes from Wits University and his team pushes these boundaries further. Forbes explains, "Traditionally, two communicating parties physically send the information from one to the other, even in the quantum realm. Now, it is possible to teleport information so that it never physically travels across the connection - a 'Star Trek' technology made real."

The Leap to High-Dimensional States
The key innovation lies in the team's ability to teleport information using high-dimensional states with just two entangled photons. Prior attempts at quantum teleportation were limited to three-dimensional states, akin to a three-pixel image, necessitating additional entangled photons for more complex transmissions. The team's successful demonstration of a 15-dimensional state transport, using a nonlinear optical detector, represents a new state-of-the-art in the field. This advancement not only makes higher-dimensional quantum transport feasible but also scalable.

Practical Applications: Enhancing Banking Security
A particularly intriguing application of this technology is illustrated in the banking sector. Imagine a scenario where a customer needs to send sensitive information, like a fingerprint, to a bank. In traditional quantum communication, this information would be physically transmitted, carrying an inherent risk of interception. The newly proposed quantum transport scheme changes this dynamic.

In this scheme, a bank sends a single photon (one of an entangled pair) with no information to the customer. The customer then overlaps it on a nonlinear detector with the information to be sent. Consequently, the information appears at the bank as if it had been teleported, with no physical transmission between the parties, rendering interception futile.

Challenges and Future Prospects
Despite its resemblance to teleportation, this protocol isn't strict teleportation, as it relies on a bright laser beam for the nonlinear detector's efficiency. Forbes notes, "It requires a bright laser beam to make the nonlinear detector efficient, so that the sender could know what is to be sent, but doesn't need to know." However, even with this limitation, the research opens new pathways for connecting quantum networks and highlights nonlinear quantum optics as a valuable resource.

Dr. Adam Valles from ICFO, who played a pivotal role in the experiment, reflects on the potential implications and future directions: "This experiment showing the feasibility of the process motivates further advances in the nonlinear optics community towards a full quantum implementation." However, he also cautions about the current configuration's limitation in preventing a cheating sender from keeping better copies of the teleported information.

Research Report:Quantum transport of high-dimensional spatial information with a nonlinear detector

Related Links
University of the Witwatersrand
Space Technology News - Applications and Research