Quantum teleportation becomes reality on active internet cables

SCITECH DAILY 

Researchers at Northwestern University have achieved a significant milestone by successfully demonstrating quantum teleportation using a fiber optic cable that also carries regular Internet traffic.

This innovation simplifies the potential integration of quantum and classical communications, offering a path toward shared infrastructure. The experiment proved that quantum information could be transmitted alongside conventional data without interference, promising more efficient and secure communication technologies.

Northwestern University engineers have achieved a groundbreaking milestone by successfully demonstrating quantum teleportation over a fiber optic cable already transmitting regular Internet traffic.

This breakthrough suggests that quantum communication could be integrated with existing Internet infrastructure, eliminating the need for dedicated networks and simplifying the technology required for quantum computing and sensing applications.

The team’s findings will be published today (December 20) in the journal Optica.

“This is incredibly exciting because nobody thought it was possible,” said Northwestern’s 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.”

An expert in quantum communication, Kumar is a professor of electrical and computer engineering at Northwestern’s McCormick School of Engineering, where he directs the Center for Photonic Communication and Computing.

Only limited by the speed of light, quantum teleportation could make communications nearly instantaneous. The process works by harnessing quantum entanglement, a technique in which two particles are linked, regardless of the distance between them. Instead of particles physically traveling to deliver information, entangled particles exchange information over great distances — without physically carrying it.

“In optical communications, all signals are converted to light,” Kumar explained. “While conventional signals for classical communications typically comprise millions of particles of light, quantum information uses single photons.”

Before Kumar’s new study, conventional wisdom suggested that individual photons would drown in cables filled with the millions of light particles carrying classical communications. It would be like a flimsy bicycle trying to navigate through a crowded tunnel of speeding heavy-duty trucks.

Kumar and his team, however, found a way to help the delicate photons steer clear of the busy traffic. After conducting in-depth studies of how light scatters within fiber optic cables, the researchers found a less crowded wavelength of light to place their photons. Then, they added special filters to reduce noise from regular Internet traffic.

“We carefully studied how light is scattered and placed our photons at a judicial point where that scattering mechanism is minimized,” Kumar said. “We found we could perform quantum communication without interference from the classical channels that are simultaneously present.”

To test the new method, Kumar and his team set up a 30-kilometer-long fiber optic cable with a photon at either end. Then, they simultaneously sent quantum information and regular Internet traffic through it. Finally, they measured the quality of the quantum information at the receiving end while executing the teleportation protocol by making quantum measurements at the mid-point. The researchers found the quantum information was successfully transmitted — even with busy Internet traffic whizzing by…