Quantum computing can revolutionize the paradigm in many industries, such as healthcare, energy safe-keepers, emerging technologies, and logistic systems. This technology’s main apparatus is qubits. However, to build a practical quantum computer, the need to cool these qubits to near absolute zero is an obstacle that needs to be overcome.
Researchers at Chalmers University of Technology, Sweden, and the University of Maryland, USA, have made a major breakthrough. They have developed a new type of refrigerator to autonomously cool superconducting qubits to record low temperatures.
For quantum computers to perform smoothly, qubits must be maintained at ultra-cold temperatures near absolute zero (-273.15°C or 0 Kelvin). Qubits can enter their low-energy state at such low temperatures, which is essential for quantum calculations.
Existing cooling systems, known as dilution refrigerators, can only cool qubits to around 50 millikelvins, just above absolute zero. Further cooling is a significant challenge because it is impossible to reach absolute zero according to the laws of thermodynamics.
The quantum refrigerator that cools superconducting qubits down to a historical 22 millikelvin to solve this challenge. This device has been extensively explained to enhance the overall performance of the quantum computer significantly.
The quantum refrigerator will operate based on interactions between a superconducting qubit and a thermal environment. In such a system, one qubit absorbs energy from the environment to run the refrigerator, which transfers energy to the second, the cold qubit, which loses the heat to a cold climate. Thus, the refrigeration process would be autonomous after its initiation since it does not require any external control at all.
“The refrigerator is powered by heat from the environment and utilizes quantum interactions to cool the target qubit,” explained Aamir Ali, lead author and research specialist at Chalmers University. “This approach increases the qubit’s probability of being in its ground state before computation to an impressive 99.97%, far surpassing previous techniques, which achieved probabilities between 99.8% and 99.92%.”
While this improvement may seem small, it compounds over multiple computations, substantially boosting quantum computers’ efficiency.
“The development of this autonomous quantum refrigerator marks a critical step toward making quantum computing more reliable and scalable. “Our work is the first demonstration of an autonomous quantum thermal machine performing a practically useful task,” said Simone Gasparinetti, Associate Professor at Chalmers University and lead author of the study. “We originally intended this experiment as a proof of concept, so we were pleasantly surprised by how well it performed.”
This breakthrough improves the cooling process and reduces errors, bringing us closer to the day when quantum computers can be used in real-world applications. It also paves the way for more powerful and efficient technologies.
As quantum computing advances, the new refrigerator could become a key component in the quest for more reliable, error-free quantum computation, with far-reaching implications for industries worldwide.
Journal Reference:
- Aamir, M.A., Jamet Suria, P., Marín Guzmán, J.A. et al. A thermally driven quantum refrigerator autonomously resets a superconducting qubit. Nat. Phys. (2025). DOI: 10.1038/s41567-024-02708-5
