All Hail Lego-Man: The New Quantum Computer Cryo-Insulator

Lego’s are more than toys?  Researchers at the University of Lancaster are studying the use of the Lego material for quantum computer cooling system insulation.  This isn’t the first time Lego’s have made it to quantum computing news (See Using Legos to Model Bigger Quantum Computers; Its About Control).  Because Quantum is Coming.  Qubit.

LEGO® Block Structures as a Sub-Kelvin Thermal Insulator


We report measurements of the thermal conductance of a structure made from commercial Acrylonitrile Butadiene Styrene (ABS) modules, known as LEGO® blocks, in the temperature range from 70 mK to 1.8 K. A power law for the sample’s thermal conductivity κ = (8.7 ± 0.3) × 10−5 T1.75±0.02 WK−1 m−1 was determined. We conclude that this ABS/void compound material provides better thermal isolation than well-known bulk insulator materials in the explored temperature range, whilst maintaining solid support. LEGO blocks represent a cheap and superlative alternative to materials such as Macor or Vespel. In our setup, <400 nW of power can heat an experimental area of 5 cm2 to over 1 K, without any significant change to the base temperature of the dilution refrigerator. This work suggests that custom-built modular materials with even better thermal performance could be readily and cheaply produced by 3D printing.


Low thermal conductivity materials are necessary for thermally isolating cryogenic components. Radiation shield spacers and support rods in dilution refrigerators are good examples of this. These components are useful for all cryogenics but especially for the current progression of quantum computing, which relies on isolated low temperatures for operation and coherence. Certain plastic materials, such as Vespel, have reasonably low thermal conductivities1, but large volumes can be costly. In this work, we show that a modular Acrylonitrile Butadiene Styrene (ABS) solid/void structure assembled from commercially available LEGO® blocks exhibit effective thermal conductivity even lower than industry-standard bulk materials, whilst offering good mechanical properties. The individual blocks readily allow affordable and repeatable large volume customization. Thermal conduction along the structure is difficult to predict from the properties of pure ABS material, since the internal thermal paths are complicated and include the solid-solid contact thermal resistance between the blocks. The results presented are characteristic of a modular ABS/void composite material constructed from typical LEGO elements.

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Source:  Nature.  D. E. Zmeev,  LEGO® Block Structures as a Sub-Kelvin Thermal Insulator…

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