Aalto University Sets New Benchmark in Quantum Computing Coherence

On July 8, 2025, physicists at Aalto University in Finland achieved a groundbreaking milestone in quantum computing by demonstrating a transmon qubit with a record-breaking coherence time of one millisecond. This accomplishment not only nearly doubles the previous maximum echo coherence time of approximately 0.6 milliseconds but also signifies a substantial leap forward in the stability and power of quantum computations. This development promises to facilitate more complex quantum logic operations and lessens the burden of error correction, a critical challenge in the field of quantum computing.

The lead researcher, Mikko Tuokkola, a PhD student at Aalto University, expressed optimism regarding the implications of this advancement. "We have just measured an echo coherence time for a transmon qubit that landed at a millisecond at maximum with a median of half a millisecond," he stated. This median reading is particularly noteworthy, as it also surpasses current recorded values, indicating a significant improvement in the performance of quantum bits (qubits).

Dr. Yoshiki Sunada, a postdoctoral researcher at Aalto University and supervisor of Tuokkola, contributed to the fabrication of the qubit chip and the development of the measurement setup. He remarked, "We have been able to reproducibly fabricate high-quality transmon qubits. The fact that this can be achieved in a cleanroom which is accessible for academic research is a testament to Finland's leading position in quantum science and technology."

The work is part of the Quantum Computing and Devices (QCD) research group at Aalto University, which operates under the auspices of the Academy of Finland Centre of Excellence in Quantum Technology (QTF) and the Finnish Quantum Flagship (FQF). Their findings were published in the prestigious peer-reviewed journal, Nature Communications, on July 24, 2025.

The significance of this achievement extends beyond just the technical aspects of qubit coherence. Longer coherence times allow quantum computers to perform error-free operations over extended periods, enabling more calculations to be executed on noisy quantum systems. This reduction in the necessity for resources dedicated to error correction is a significant step toward the future of noiseless quantum computing.

Professor Mikko Möttönen, head of the QCD group, emphasized the broad implications of their findings. He stated, "This landmark achievement has strengthened Finland's standing as a global leader in the field, moving the needle forward on what can be made possible with the quantum computers of the future." He also noted that achieving advancements in noise reduction, increasing the number of qubits, and improving coherence times are critical for the scaling up of future quantum computers.

This achievement reflects the high standards of research and development within Finland's national research infrastructure for micro-, nano-, and quantum technologies, particularly at the Micronova cleanrooms at OtaNano. The QCD group's success in achieving this coherence milestone not only showcases Finland's capabilities in quantum technology but also provides a foundation for further advancements in the field.

As the QCD group prepares to accelerate future breakthroughs, they have opened new positions for senior staff and postdoctoral researchers, signaling an ongoing commitment to innovation in quantum computing. This progress highlights a pivotal moment in the evolution of quantum technologies, potentially charting the course for enhanced computational capabilities in the coming years.