Quantum Computing’s Cooling Challenge: A Budding Components Industry Offers a Solution
Table of Contents
A new ecosystem of specialized component suppliers is emerging to address the extreme cooling and space constraints hindering the progress of quantum computers, potentially unlocking significant gains in processing power. for years, quantum computing companies have been forced to develop solutions to these challenges in-house. However, as the field matures, off-the-shelf components are becoming increasingly available, mirroring the evolution of the classical computing industry.
The Cryogenic Bottleneck
Both superconducting and silicon spin qubits – two leading quantum computing technologies – demand incredibly low temperatures, around 20 millikelvin (-273.13 °C), to prevent thermal noise from disrupting calculations. Maintaining these temperatures requires specialized dilution refrigerators, but these devices have limited space and, crucially, limited cooling power. Cooling power diminishes exponentially as temperatures approach absolute zero, creating a significant hurdle for scaling up quantum systems.
conventional control electronics generate too much heat to be housed within these refrigerators. Currently, quantum computers rely on external racks of hardware connected to qubits via bulky cabling. This approach is inefficient, consuming valuable space and introducing additional latency. Researchers at Google have demonstrated controlling around 100 qubits within two years.
Amplifying Progress, Reducing Heat
Another critical component, and a major source of heat, is the signal amplifier. The weak output signals from qubits require substantial amplification before they can be processed. However, traditional amplifiers can consume up to 50% of a dilution refrigerator’s cooling budget.
Qubic Technologies, a Canadian startup, is pioneering a novel superconducting amplifier that could reduce heat dissipation by a factor of 10,000. Dilution fridges operate in stages, with the coldest stages utilizing superconducting amplifiers based on Josephson junctions to minimize heat generation. However,these amplifiers don’t provide sufficient signal boost to exit the fridge,necessitating additional,heat-producing semiconductor amplifiers at warmer stages. “At some point, you reach a breaking point where you don’t have enough cooling power accessible to remove the heat from the amplifiers,” explains Jérôme Bourassa, CEO of Qubic Technologies.
Qubic’s design utilizes waveguides made from a proprietary niobium alloy, achieving comparable signal amplification to conventional methods while drastically reducing heat. While current designs exhibit some noise, the goal is to deploy these amplifiers as a drop-in replacement for existing semiconductor amplifiers, hitting the market in 2026.
Rethinking Quantum Cabling
Even the cabling connecting qubits to control systems presents a challenge. Current coaxial cables are bulky, conduct heat, and require numerous connections, each a potential point of failure.
Delft Circuits, a Dutch startup, has developed a superconducting flex cable that addresses these issues. Resembling flexible printed circuit boards, these cables feature eight adjacent wires – silver for stages above 4K and a niobium-titanium superconductor for colder stages – substantially reducing heat transfer and the number of connections required. The design integrates signal filters directly into the cable,reducing the connector count to just two. Delft Circuits envisions a future “quantum motherboard” – a 2D sheet integrating various components at cryogenic temperatures, leveraging a chiplet architecture.
The Path to Scalable Quantum Computing
These innovations collectively address the critical need to conserve both space and cooling capacity. As Bourassa of Qubic Technologies notes, “Having the capacity to remove the heat, having the capacity to make your systems more compact is definitely the pathway towards something that is viable in the future, both in terms of power but also economically.” The emergence of a specialized quantum components industry signals a crucial step toward realizing the full potential of quantum computing, mirroring the ancient development of classical computing where specialized sectors emerged to accelerate progress.
