Yorktown Heights, New York — 19 August 2026. IBM announced it has successfully joined and cooled down two cryogenic modules into a single shared environment, a milestone in the engineering required to link hundreds of quantum chips into a larger, more powerful quantum computer. The modules were cooled to below 15 millikelvin — more than 180 times colder than deep space — marking a step forward in the systems engineering needed for fault-tolerant quantum computation.
The announcement advances IBM's quantum roadmap toward delivering IBM Quantum Starling in 2029, which the company expects to be the world's first large-scale fault-tolerant quantum computer. Starling is designed to integrate advances across error correction, processor design, decoding, and systems engineering.
The Modular Cryogenic Challenge
Quantum computers require their processors to be maintained at temperatures near absolute zero to preserve quantum coherence. Until now, commercial quantum systems have typically housed a single processor within one cryogenic enclosure — a dilution refrigerator that cools the quantum chip to millikelvin temperatures.
Scaling beyond a single processor presents a fundamental engineering challenge: how to physically connect multiple quantum chips while maintaining the ultra-cold environment they require. Any thermal leak between modules can destroy quantum states, and the wiring and interconnects needed to share quantum information between chips must operate within the same cryogenic envelope.
IBM's new architecture addresses this by creating a shared, modular cryogenic environment. The first two operational modules stand more than 8 feet tall and 8 feet wide combined. Initial tests, documented on Zenodo, demonstrated that the two modules can jointly cool down to 4 Kelvin (the temperature of liquid helium) in under 5 days, reaching a final temperature below 15 millikelvin shortly after.
L-Coupler Technology and Chip-to-Chip Communication
The key innovation enabling modular quantum systems is IBM's "L-coupler" technology. L-couplers connect separate quantum chips together to share information, communicate, and operate as part of a larger quantum computer. IBM's box-shaped cryogenic module design allows modules to connect in a tight row and use the expanded wiring space to directly link quantum processors through these couplers.
This approach contrasts with alternative scaling strategies that rely on photonic interconnects or cryogenic links between separate refrigerators. By placing multiple chips within a single shared cryogenic environment, IBM aims to reduce the latency and complexity of inter-chip quantum communication.
By 2027, IBM's roadmap plans to use L-couplers to link multiple processors into a larger quantum computer with at least 1,000 programmable qubits — qubits that can be directly used to perform computations. Later this year, IBM will install IBM Quantum Nighthawk processors into the cryogenic modules to expand operational performance testing. At the time Starling is delivered, IBM plans for each cryogenic module to house thousands of qubits.
The Path to Fault Tolerance
Fault-tolerant quantum computing requires more than raw qubit counts. It depends on quantum error correction — encoding logical qubits across many physical qubits so that errors in individual qubits can be detected and corrected without destroying the quantum computation.
IBM's plans for Starling were introduced in 2024 with a new error correction code, published in Nature, that dramatically reduces the physical resources required for fault tolerance. Since then, the company has reported progress on core hardware components and breakthroughs in efficient error-correction decoding.
The modular cryogenic architecture addresses another critical hurdle: the ability to independently test, improve, and rapidly iterate on individual system components. Three essential components of IBM Quantum System Two's environment are built into the new architecture, but in a way that allows each part to be upgraded without redesigning the entire system.
"Bringing fault-tolerant quantum computers to industries depends on several fundamental advances," said Jay Gambetta, Director of IBM Research and IBM Fellow. "The successful connection and operation of these cryogenic modules signals a leap forward in that direction and will accelerate our progress alongside continued innovation in quantum hardware, software, and algorithms."
Why Modular Scaling Matters
The significance of IBM's modular cryogenic milestone extends beyond the specific hardware achievement. It addresses one of the central challenges in quantum computing: the gap between laboratory demonstrations of small quantum systems and the construction of practical machines capable of solving real-world problems.
Current quantum processors operate in the noisy intermediate-scale quantum (NISQ) regime, where qubits are too few and too error-prone for fault-tolerant computation. Scaling to the thousands or millions of physical qubits needed for useful fault-tolerant quantum computing requires solving not just quantum physics problems but also classical engineering challenges — cryogenics, wiring, control electronics, and thermal management — at unprecedented scales.
The Competitive Landscape
IBM is not alone in pursuing fault-tolerant quantum computing. Google's Willow processor, announced in December 2024, demonstrated quantum error correction below the surface code threshold — a critical theoretical milestone showing that errors can be suppressed as the system scales. Other approaches, including trapped-ion systems from companies like Quantinuum and neutral-atom arrays from QuEra, offer different trade-offs between qubit coherence times, gate speeds, and scalability.
IBM's differentiation lies in its superconducting qubit platform and its systematic roadmap approach — announcing specific milestones (new processors, error correction codes, and now modular cryogenics) on a timeline aimed at delivering a fault-tolerant system by 2029. Whether this timeline holds remains to be seen, but the modular cryogenic milestone demonstrates that the company is addressing the full stack of engineering challenges, not just the quantum processor itself.
Sources
- IBM Newsroom, "IBM Connects Its First Modular Cryogenic Systems in Milestone Toward Fault-Tolerant Quantum Computing," 19 August 2026
- IBM Quantum Blog, modular cryogenics post
- Zenodo, initial test data record
- Nature, IBM error correction code paper (2024)
- IBM Quantum roadmap, 2026
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Institutional Research Desk · Foresight Institute of Research and Translation
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