What just happened? An engineering team at Northwestern University has achieved a breakthrough in quantum teleportation, demonstrating the feasibility of transmitting quantum information alongside classic internet traffic. As research advances, we could enter a new era in communication technology, where quantum and traditional networks can coexist to offer unprecedented levels of security and speed.
Engineers at Northwestern University have demonstrated quantum teleportation over a fiber optic cable already carrying Internet traffic. This feat, published in the journal Optica, opens up new possibilities for combining quantum communication with existing Internet infrastructure. It also has major implications for the field of advanced sensing technologies and quantum computing applications.
Quantum teleportation, a process that harnesses the power of quantum entanglement, enables an ultra-fast and secure method of information sharing between distant network users. Unlike traditional communication methods, quantum teleportation does not require the physical transmission of particles. Instead, it relies on entangled particles exchanging information over great distances.
Nobody thought it would be possible to achieve this, according to Professor Prem Kumar, who led the study. "Our work shows a path towards next-generation quantum and classical networks sharing a unified fiber optic infrastructure. Basically, it opens the door to pushing quantum communications to the next level."
"By performing a destructive measurement on two photons – one carrying a quantum state and one entangled with another photon – the quantum state is transferred onto the remaining photon, which can be very far away," said Jordan Thomas, a Ph.D. candidate in Kumar's laboratory and the paper's first author. "The photon itself does not have to be sent over long distances, but its state still ends up encoded onto the distant photon."
Prior to this study, many researchers were skeptical about the feasibility of quantum teleportation in cables carrying classic communications. The concern was that the entangled photons would be overwhelmed by the millions of other light particles present in the fiber optic cables.
However, Kumar and his team were able to devise a solution. Through extensive studies of light scattering within fiber optic cables, the researchers identified a less crowded wavelength of light to place their photons. They also implemented special filters to reduce noise from regular Internet traffic. Kumar explained that he and his team conducted a meticulous analysis of light scattering patterns and strategically positioned their photons at a critical point where the scattering effect was minimized.
To validate their method, the team set up a 30-kilometer-long (18.6 miles) fiber optic cable with a photon at each end. They simultaneously transmitted quantum information and high-speed Internet traffic through the cable. The quality of the quantum information was measured at the receiving end while executing the teleportation protocol by making quantum measurements at the mid-point. The results showed that the quantum information was successfully transmitted, even in the presence of busy internet traffic.
Looking ahead, Kumar and his team have plans to extend their experiments over longer distances. They aim to demonstrate entanglement swapping using two pairs of entangled photons, which would mark another crucial milestone in the development of distributed quantum applications. Additionally, the researchers are exploring the possibility of conducting experiments over real-world in-ground optical cables, moving beyond laboratory settings.
"Quantum teleportation has the ability to provide quantum connectivity securely between geographically distant nodes," Kumar said. "But many people have long assumed that nobody would build specialized infrastructure to send particles of light. If we choose the wavelengths properly, we won't have to build new infrastructure. Classical communications and quantum communications can coexist."
Engineers achieve quantum teleportation over active internet cables
