The burgeoning of quantum technologies could reshape the enterprise landscape, giving regulated industries unparalleled computing capabilities to solve more complex problems and new ways to help protect highly sensitive data. Yet the industry’s next obstacle is less about building a single larger processor capable of delivering those benefits than connecting many smaller systems reliably enough to work together.
Networking could allow these separate systems to contribute to a larger computing environment rather than remain isolated machines. However, that depends on reconciling their differences so quantum information can move between systems without being compromised.
That will require switching technology, says Ramana Kompella, Head of Cisco Research. “If you truly want to scale it to interconnect more than hundred nodes, thousand nodes or a million nodes even, you need the switching technology,” Kompella told UC Today. The challenge is not simply creating more connections, but ensuring disparate systems can exchange quantum information reliably.
The Quantum Conundrum
Classical networks became globally useful because routers could move traffic between billions of endpoints regardless of the underlying devices. Quantum networks are still closer to the internet’s early point-to-point phase: specialist nodes can be linked, but turning those connections into a flexible network spanning many systems is a harder task.
The difficulty is that quantum information cannot be treated like conventional network traffic. It must retain the fragile quantum state that carries the information as it moves between systems, even where those systems use different technologies and encoding methods. If that state is degraded or destroyed in transit, the systems cannot reliably distribute the entanglement needed for quantum networking.
That limitation matters because the quantum industry is not converging on one type of machine. Kompella points to superconducting, trapped-ion, neutral-atom and photonic systems, each of which may be suited to different tasks:
“We don’t believe in the future where there’s only one technology.”
For organizations, the implication is that the network cannot be an afterthought: without an interoperable layer, quantum systems risk remaining isolated specialist resources.
For quantum technologies to become genuinely usable beyond specialist research environments, the industry will need common ways to connect, manage and measure different systems. The US National Institute of Standards and Technology identifies quantum interfaces that preserve quantum properties during conversion as necessary for connecting quantum computers, while its network testbeds are examining issues including control planes, synchronization, device performance and the coexistence of classical and quantum traffic. The message for businesses is that useful quantum infrastructure will depend on a broader networking ecosystem.
What Can Businesses Do About It?
One answer is a switching layer built specifically for quantum information. In a conventional network, switches direct traffic to its destination. In a quantum network, they would need to route photons between systems while preserving the quantum state encoded within them. Commercial optical switches can already direct photons, but as Kompella states, that alone is not enough:
