Reference News Network — April 17
On April 11, the website of the UK’s New Scientist published an article titled “New York City Is Building a Quantum Internet That Hackers Can’t Breach,” by Carmela Padavic-Callaghan. An excerpt follows:
Beneath the bustling streets of New York City, researchers are sending entangled photons through standard fiber-optic loops—a crucial first step toward building a quantum internet that is fundamentally unhackable.
In an office in Brooklyn overlooking a historic shipyard, I was told that on my way here, I might have walked directly above some of these entangled photons.
Since the previous evening, researchers from the U.S.-based company Qunnect had been transmitting particles of light—photons—through a 34-kilometer underground fiber loop beneath New York City. Their method preserves the delicate quantum property of entanglement, paving the way to eventually repurpose this existing fiber infrastructure as the backbone of a quantum internet.
In a quantum internet, devices communicate by exchanging quantum particles such as photons, which can encode vast amounts of complex information simultaneously. This encoding process is fundamentally different from how electronic signals transmit data between our computers and smartphones, as it leverages uniquely quantum properties that classical objects do not possess. The greatest promise of quantum networks lies in their ability to transmit information more securely than any existing network—making online communications virtually impossible to intercept or decode.
The cornerstone of this security is quantum entanglement. When two particles are entangled, any attempt to tamper with one instantly alters the state of the other—a change that immediately alerts users to a potential breach.
To build this test network, Qunnect’s researchers developed a device called an “entanglement source” capable of generating entangled photons. It uses precisely tuned lasers directed at rubidium atoms, which then emit pairs of entangled photons. About the size of a shoebox and operable at room temperature, the device can be seamlessly integrated into existing fiber-optic networks.
Mehdi Namazi, Qunnect’s Chief Science Officer, said the device produces entangled photon pairs at an unprecedented rate and fidelity—100 times faster than previous atom-based systems.
By the time I saw Qunnect’s entanglement source, the experiment had already been running for over 12 hours. For every pair of entangled photons generated, researchers kept one photon in the lab while sending the other into the fiber loop. Tens of thousands of photons circled the loop every second.
Other quantum networks already exist. One in Hefei, China, connects multiple quantum devices. Smaller-scale quantum networks have also been established in Bristol (UK), Chattanooga, Tennessee, and Chicago, Illinois (USA). Plans are also underway to build a quantum network in Rotterdam, Europe’s largest seaport.
However, these networks cannot easily integrate with existing telecom infrastructure. Instead of using rubidium atoms, they rely on crystals that emit entangled photons when struck by lasers. While this approach yields more photons—and thus higher data capacity—the resulting photons operate at wavelengths incompatible with today’s standard fiber-optic networks.
Noel Godard, CEO of Qunnect, said the team’s long-term goal is to keep this setup permanently active while continuously adding new components—such as quantum memory devices for storing information—without disrupting New York’s existing fiber infrastructure. “After all,” she noted, “the world isn’t going to lay entirely new fiber networks just to support a quantum internet.”
Researchers are now working to add a second fiber loop and another entanglement source to their setup. This expansion will bring them closer to realizing a true quantum internet—one with multiple quantum telecom hubs, each equipped with its own entanglement source, giving users more options for distributing entangled photons.
Godard acknowledged it’s hard to predict all future applications for these photons, but Qunnect aims to offer its technology to financial institutions and research organizations—particularly those requiring ultra-secure communications or operating quantum computers.
