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A Melon-Sized Fridge Chills Quantum Chips in Two Hours ✛

Original: "An ultracompact dilution refrigerator for fast quantum device characterization"
· Clment Geffroy, Dorian Nicolas, Eric Eyraud, Shelender Kumar, Supriya Mandal, Julien Jarreau, Laura Kowalski, Laurent Del-Rey, Didier Dufeu, Nicolas Roch, Wolfgang Wernsdorfer, Quentin Ficheux, Matias Urdampilleta
arXiv:2608.18699v1 · 2026-08-19 · CC BY 4.0 · 1 min
Quantum Physics Mesoscale
A 3 kg cryostat brings qubits to their operating temperature of 70 mK and lets you measure their fidelity up to 99%.

Superconducting qubits are tiny electrical circuits that only work in extreme cold, around 70 thousandths of a kelvin. A typical fridge for such temperatures is the size of a wardrobe and takes nearly a day to cool down. Engineers have built a device that weighs 3 kg and is 10 cm in diameter — about the size of a small melon. It cools a chip to the required temperature in 2 hours.

The secret lies in three cooling stages: one quickly removes the bulk of the heat, a second drops the temperature to 4 kelvins, and a third brings it down to 70 millikelvins. Together, they take 2.1 hours instead of the usual day.

They tested a chip with two qubits on this fridge. They were able to measure their energy parameters, lifetimes, and operation fidelity — up to 99.03%. This shows that fast cooling doesn't hinder quantum computation. Now new prototypes can be tested more quickly, speeding up the development of quantum devices.

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The cryostat weighs just 3 kg, about the same as a small melon, and its 100 mm diameter allows it to fit into the bore of a high-field magnet.

The idea of modular cryogenic systems connected by quantum channels echoes the concept of a distributed quantum computer in Neal Stephenson's novel 'Anathem'.

H = 4 E_C \hat{n}^2 + \frac{1}{2} E_L (\hat{\varphi} + \varphi_{\text{ext}})^2 - E_J \cos(\hat{\varphi})
The qubit energy consists of charging, inductive, and Josephson contributions
\frac{1}{T_{1,\text{diel}}} = \frac{\hbar \omega_{01}^2}{4 E_C Q_{\text{cap}}(\omega_{01})} \coth\left(\frac{\hbar \omega_{01}}{2 k_B T_{\text{bath}}^{\text{eff}}}\right) |\langle 0 | \varphi | 1 \rangle|^2
Relates T1 to the transition frequency, capacitor quality factor, and bath temperature
Scientists
Klaus von KlitzingLev LandauAlexander HolevoAsher PeresBenjamin SchumacherCharles Bennett
Concepts
cryogenic microwave measurement cryostat supercooling liquid helium temperature cooling millikelvin liquid helium ibm quantum processor quantum computing technology superconducting qubit cryogenic temperature refrigerator superconducting wire rubidium power consumption microwave signal laser cooling absolute zero ultracold atoms microchip