Researchers unveil first superconducting quantum heat engine, a step toward scalable quantum computers

Scientists at Aalto University have built the world’s first superconducting quantum heat engine, a nanofabricated device that turns ultra-low-temperature heat into measurable work. Using a transmon qubit linked to a resonator and a quantum-circuit refrigerator, the team executed an Otto cycle within a cryostat close to absolute zero, confirming that heat passing through the qubit yields positive work. The engine’s single refrigerator serves as both heating and cooling source, streamlining operation.

Led by Academy Professor Mikko Möttönen and reported in Nature Communications, the work showcases how quantum thermodynamics can be harnessed for technology. Researchers aim to develop fully autonomous engines that could read out qubits without external microwave lines, potentially cutting the massive cable infrastructure required for future machines with hundreds of thousands of physical qubits. Funding came from the Research Council of Finland and the Finnish Cultural Foundation, with experiments conducted on the OtaNano platform.