IBM links two quantum processors with a new cooling system

IBM has successfully linked two cryogenic cells, demonstrating a new modular architecture designed to connect quantum processors and overcome the limitations of single-chip scaling. The company reports this demonstration provides early validation for its approach to building fault-tolerant quantum computers, a crucial step toward systems capable of tackling more complex algorithms. This new architecture, which utilizes both quantum and classical links to move information between chips, forms a foundational component of IBM Quantum Starling, the company’s first fault-tolerant quantum computer, expected by 2029.

IBM’s Cryogenic Cells Enable Inter-Processor Quantum Connections

This achievement moves beyond single-chip limitations by enabling information transfer between processors via both quantum and classical links, a crucial step toward extending computational power. Each cryogenic “cell” utilizes established dilution refrigerator technology but departs from cylindrical designs, instead adopting a box-shaped format constructed from solid aluminum panels. The modular design allows cells to sit side-by-side with shorter interconnect paths, reducing signal degradation and overhead compared to traditional systems.

This architecture addresses not only physical connection but also the practicalities of maintenance and future upgrades. Each cell contains its own vacuum chamber, cooling hardware, and thermal shielding, simplifying component replacement without disrupting the entire system. According to IBM documentation, “Even when linked together, the design of the shield layers keeps the thermal interaction between adjacent cells to a minimum.”

The prototypes, currently operating in Poughkeepsie, New York, provide approximately 0.53 square meters of available wiring area and 2.75 cubic meters of vacuum chamber volume. IBM states that this architecture is specifically tailored to its long-term goals for connected multi-chip quantum systems, aligning with advancements in readout wiring, processor designs, and cryoelectronics, and future versions of single cells are expected to support at least 2,000 qubits each.

Two-Cell Prototype Validates Modular Architecture for IBM Quantum

IBM verified the viability of a new approach to quantum computer cooling by successfully demonstrating the coupling of two cryogenic cells in Poughkeepsie, New York. This demonstration moves beyond the limitations of single-chip scaling, a challenge stemming from spatial constraints, heat generation, and qubit crosstalk, by establishing a modular architecture for future quantum systems.

Unlike traditional cylindrical cryostats, these box-shaped cells allow for tighter positioning, minimizing interconnect path lengths and reducing signal degradation as quantum information travels between processors. Even when linked, the design minimizes thermal interaction between cells, maintaining consistent cool-down times and temperature stability.

L-Couplers and Cryostat Size Support 2029 Fault Tolerance Goals

Beyond simply increasing cooling capacity, this new system is designed to facilitate the complex interconnections necessary for multi-chip quantum processing. Researchers have successfully coupled two cryogenic cells, demonstrating a crucial element of this future scalability. This modular design diverges from traditional cryostat construction by utilizing box-shaped “cells” constructed from aluminum, each providing approximately 0.53 square meters of wiring area and 2.75 cubic meters of vacuum chamber volume.

The architecture also supports the integration of l-couplers, long-range quantum interconnects first demonstrated in 2024, which enable communication between quantum processing units on a one-meter scale. These l-couplers are not merely an addition, but a planned component for researchers to explore before Starling’s arrival, allowing validation of key capabilities in quantum hardware.

With future versions of single cells expected to be capable of supporting at least 2,000 qubits each, the modular approach addresses the limitations of single-chip scaling and introduces infrastructure capable of supporting larger quantum systems. By providing a platform for testing these interconnects and larger processors, IBM aims to build a bridge between current single-chip deployments and the interconnected systems envisioned on its quantum roadmap.