On July 8, 2025, researchers at Aalto University in Finland announced a breakthrough in quantum computing, reporting a transmon qubit coherence time that surpassed all previous scientific records. Their measurement reached the millisecond range—well beyond the prior record of approximately 0.6 milliseconds—marking a major leap in computing power and sparking efforts by other scientists to replicate the achievement.

Extending coherence times allows quantum computers to function more reliably for longer durations, enabling them to handle more complex operations despite the presence of noise. This reduces the need for extensive quantum error correction and brings researchers closer to realizing fault-tolerant quantum computing.

Figure 1. High-Coherence Transmon Qubit Integrated on a Quantum Processor

“We’ve measured an echo coherence time for a transmon qubit reaching up to a millisecond, with a median of half a millisecond,” said Mikko Tuokkola, the PhD student who carried out and analyzed the measurements. The median value is especially notable, as it exceeds previously recorded benchmarks. Figure 1 shows High-Coherence Transmon Qubit Integrated on a Quantum Processor.

The findings were recently published in the prestigious peer-reviewed journal Nature Communications. The researchers provided a detailed account of their methodology to ensure that other research teams worldwide can replicate the results.

Finland Strengthens Its Leadership in Quantum Research

At Aalto University, Mikko Tuokkala carried out his research under the supervision of postdoctoral researcher Dr. Yoshiki Sunada, who designed the chip and built the experimental measurement setup. “We’ve consistently fabricated high-quality transmon qubits, and doing so in a cleanroom accessible to academic researchers highlights Finland’s strong leadership in quantum science and technology,” said Sunada, who is now based at Stanford University in the U.S.

This breakthrough was achieved by the Quantum Computing and Devices (QCD) research group at Aalto University, part of the Department of Applied Physics, the Academy of Finland Centre of Excellence in Quantum Technology (QTF), and the Finnish Quantum Flagship (FQF).

The transmon qubit was fabricated by the QCD group using high-quality superconducting film provided by the Technical Research Centre of Finland (VTT) [1]. The result underscores the exceptional capabilities of Micronova cleanrooms at OtaNano—Finland’s national infrastructure for micro-, nano-, and quantum technologies.

Scaling up quantum computers requires progress in multiple areas, including noise reduction, increasing qubit counts, and extending qubit coherence times—the focus of QCD’s recent findings. To accelerate further breakthroughs, the group has announced openings for a senior staff member and two postdoctoral researchers.

References:

1. https://scitechdaily.com/physicists-break-quantum-barrier-with-record-breaking-qubit-coherence/

Cite this article:

Janani R (2025), Physicists Set New Record for Qubit Coherence, Pushing Quantum Limits, AnaTechMaz, pp.332