University of Illinois builds scalable modular superconducting quantum processors

Researchers from the University of Illinois Urbana-Champaign have developed a modular quantum computing architecture that connects superconducting quantum processors like building blocks.

This method aims to make quantum computers larger and more reliable by connecting smaller, high-quality devices with efficient superconducting cables.

The team demonstrated approximately 99% fidelity in SWAP gate operations between separate quantum modules, a performance that rivals permanently bonded systems, enabling flexible reconfiguration and error detection before full assembly.

Published in Nature Electronics, this work represents a significant step in building scalable, fault-tolerant quantum computers.

What is the breakthrough in modular quantum computing?

The key innovation is modularity: researchers build smaller, interconnected processor modules rather than a monolithic quantum computer. This modular approach allows easier scalability, hardware upgrades, and error management.

Wolfgang Pfaff, senior author and assistant professor of physics, explained that their design enables connecting and manipulating qubits across modules with high quality and flexibility.

Did you know?
The team achieved approximately 99% fidelity in SWAP gate operations between separate quantum devices connected by superconducting coaxial cables.

How do superconducting quantum processors connect like building blocks?

The processors are linked using superconducting coaxial cables that act like quantum data highways. Custom connectors position cables with sub-millimeter precision to enable effective gates between qubits and cables.

This design allows for the connection, disconnection, and reconfiguration of devices, enabling high-speed, low-loss quantum gate operations essential for multi-module quantum systems.

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What challenges remain in scaling modular quantum systems?

While we have successfully linked two modules with excellent fidelity, the next key challenge is scaling to more devices while maintaining error correction and coherence.

The current hardware impacts qubit coherence, and overcoming these losses is critical to building practical large-scale quantum computers.

Why is this breakthrough important for future quantum applications?

Modular quantum computing provides a path toward the millions of qubits needed for applications in drug discovery, cryptography, and materials science.

By enabling scalable, fault-tolerant, and reconfigurable systems, this research brings quantum computing closer to solving problems beyond classical capabilities and accelerates the development of practical quantum technology.