Finnish scientists have set a new international benchmark in quantum computing by achieving a one-millisecond coherence time for a transmon qubit.
The result, announced by Aalto University on Tuesday, was published in Nature Communications. It marks the longest coherence ever measured for this type of superconducting qubit.
The experiment was conducted by the Quantum Computing and Devices (QCD) research group at Aalto University’s Department of Applied Physics.
The group forms part of the Academy of Finland Centre of Excellence in Quantum Technology and the Finnish Quantum Flagship.
The researchers recorded a maximum echo coherence time of one millisecond and a median of 0.5 milliseconds. The previous record stood at approximately 0.6 milliseconds.
Qubit coherence time determines how long a quantum bit can retain its quantum state before losing information. Longer coherence times enable more operations to be performed with fewer errors.
“Achieving millisecond-level coherence means fewer resources are needed for error correction and more operations can be carried out on noisy quantum systems,” said Mikko Möttönen, professor of quantum technology and head of the QCD group.
The transmon qubit was fabricated by the QCD team using superconducting film supplied by the Technical Research Centre of Finland.
Quantum systems are highly sensitive to environmental noise, and achieving long coherence in such systems has been a major challenge globally. This milestone moves quantum computing closer to practical, fault-tolerant systems.
The Aalto team’s fabrication process and experimental techniques were developed in-house. The announcement also included a call for new research staff to continue advancing the project.
“This result confirms Finland’s role in pushing the boundaries of what is achievable in quantum technology,” Möttönen added.
HT
