Scientists Take a Step Toward a Quantum Internet Using New York City's Fiber

Why It Matters

The breakthrough proves that secure quantum communication can be built on real‑world infrastructure, accelerating the rollout of quantum key distribution and future quantum‑grade networks. It positions dense urban centers like New York as early adopters of a quantum‑enhanced internet.

Key Takeaways

• Entanglement swapping achieved across three city nodes using existing fiber
• Swapping rate reached ~1.5 events per second, maintaining quantum correlations
• Central hub uses cryogenic detectors; outer nodes require only standard hardware
• Demonstration paves way for scalable quantum key distribution in metropolitan areas

Pulse Analysis

The quantum internet has long been a theoretical goal, promising security guaranteed by the laws of physics rather than computational complexity. Central to that vision is entanglement swapping, a process that stitches together short quantum links into a larger network. While laboratory experiments have shown the principle, scaling it to real‑world distances has been hampered by photon loss and environmental noise. By leveraging New York’s dense fiber backbone, the NYU‑Qunnect‑Cisco team demonstrated that entanglement swapping can operate reliably across a metropolitan area, signaling a pivotal shift from controlled labs to commercial infrastructure.

The experiment employed a hub‑and‑spoke topology: two peripheral nodes at Qunnect’s Brooklyn Navy Yard facility connected to a Manhattan data‑center hub housing cryogenic photon detectors. Qunnect’s Carina hardware generated and stabilized polarization‑entangled photons, while Cisco’s orchestration software synchronized the three sites. The system achieved roughly 1.5 successful swapping events per second, a rate sufficient to support quantum key distribution (QKD) over city‑wide distances. Crucially, only the central hub required expensive cooling, meaning additional nodes can be added with minimal cost, a design that aligns with the economics of existing telecom networks.

For industry, especially the financial sector concentrated in Manhattan, the ability to distribute encryption keys that are provably tamper‑evident could redefine data security standards. Beyond QKD, a scalable quantum network lays the groundwork for linking future quantum processors and enabling distributed quantum sensing. New York’s compact geography and high‑value data ecosystem make it an ideal proving ground, and the partnership model demonstrated here—academia, startup, and incumbent telecom—offers a replicable blueprint for other cities. As the technology matures, we can expect incremental deployments over the next decade, gradually transforming the internet’s security foundation.