A thermionic cooler for chips has been developed it

A thermionic cooler for chips has been developed – it will help in the development of quantum computers of the future

A research team at the Finnish technical research center VTT has developed a device that enables fully electronic cooling, potentially reducing cooling costs for quantum computers by a factor of ten. Already during the experiments, the technology developed made it possible to reduce the temperature by 40%. This research could greatly simplify the development of energy-efficient and productive quantum computers.

    Image source: Quantware

Image source: Quantware

Many quantum computers use transmones, superconducting qubits, to do useful computing work. This technology is chosen by many companies involved in quantum advancement, such as IBM, Google, Amazon and others. These superconducting qubits require temperatures close to absolute zero to function. The need to mix different helium isotopes to achieve ideal operating temperatures adds complexity.

One of the fundamental limitations of any high-level computing is the ability to dissipate the resulting heat. Heat is one of the most challenging technical problems in modern computer systems. However, quantum computers have even higher cooling requirements than traditional electronics: they are more sensitive to external interference and less resistant to various types of interference. Therefore, new methods are needed to enable simpler and more efficient cooling. To date, most cooling systems have been based on extracting a coolant (e.g. water or air) from a heat source.

VTT scientists have developed a thermionic device that dissipates heat in the form of released electrons. The transfer of energy when electric current passes through the contact point (connection point) of two different conductors has been known since 1834 as the Peltier effect. The researchers believe that their approach to exploiting this effect can cool electronic components to temperatures between 1.5 K and 0.1 K.

Layers of material are placed on top of each other and connected by tunnel connections through which an electric current flows, resulting in sequential heat dissipation from layer to layer. The lowest temperature is achieved on the top layer – the chip used for computing.

    Image source: VTT

Image source: VTT

One of the problems with thermionic coolers is that other particles besides electrons interact with each other, and often the cooling achieved by removing electrons is lost due to the “return” of heat by other particles as they interact with cooled material. This process is called “backscattering”. The advantage of the new thermionic device is said to be that returning particles can be prevented from interacting with a previously cooled surface and thereby heating it.

The developers claim that their development will make it possible to create relatively inexpensive and compact cooling devices that are superior to classic liquid heat removal systems. “Our technology can help the industry reduce the overall size of a quantum computing system.”the researchers are sure.

This technology is still in the development phase, but it is already clear that the successful development of both quantum and classical computing systems requires fundamental breakthroughs in cooling. While the future of the new thermionic device is unclear, it at least removes some hurdles and offers smaller, more efficient cooling solutions.


About the author

Dylan Harris

Dylan Harris is fascinated by tests and reviews of computer hardware.

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