Swansea Physicists Achieve Major Antihydrogen Breakthrough at CERN

Physicists from Swansea University have made a significant advancement in antihydrogen research at CERN, increasing the trapping rate of antihydrogen by a factor of ten. This groundbreaking development, part of the international Antihydrogen Laser Physics Apparatus (ALPHA) collaboration, was published in Nature Communications on November 18, 2025. The findings aim to address a fundamental question in physics: why is there such a profound imbalance between matter and antimatter in the universe?

According to the Big Bang theory, equal amounts of matter and antimatter were created at the universe’s inception. Yet, the observable universe is predominantly composed of matter. Antihydrogen, the “mirror version” of hydrogen formed from an antiproton and a positron, serves as a critical tool for scientists investigating these mysteries. By trapping and studying antihydrogen, researchers can explore how antimatter behaves and whether it adheres to the same physical laws as matter.

The process of producing and trapping antihydrogen has been historically complex. Previous methods required up to 24 hours to trap merely 2,000 atoms, which severely limited experimental opportunities. The Swansea-led team has revolutionized this process. By utilizing laser-cooled beryllium ions, they successfully cooled positrons to below 10 Kelvin (approximately -263°C), notably lower than the previous threshold of around 15 Kelvin. This innovation led to a record achievement of trapping 15,000 atoms in less than seven hours.

New Era for Antihydrogen Research

This advancement marks a new era for the ALPHA collaboration, broadening the spectrum of possible experiments and enabling more precise investigations into fundamental physics. Key areas of focus include studying how antimatter responds to gravity and whether it follows the same symmetries as matter.

Professor Niels Madsen, the lead author of the study and Deputy Spokesperson for ALPHA, expressed his excitement about the breakthrough. “It’s more than a decade since I first realized that this was the way forward, so it’s incredibly gratifying to see the spectacular outcome that will lead to many new exciting measurements on antihydrogen,” he stated.

Ph.D. student Maria Gonçalves, a prominent contributor to the project, reflected on the culmination of years of effort. “The first successful attempt instantly improved the previous method by a factor of two, giving us 36 antihydrogen atoms—my new favorite number! It was a very exciting project to be a part of, and I’m looking forward to seeing what pioneering measurements this technique has made possible,” she noted.

Dr. Kurt Thompson, another key researcher on the project, highlighted the collaborative nature of the achievement. “This fantastic accomplishment was the result of the dedication and collaborative efforts of many Swansea graduate students, summer students, and researchers over the past decade,” he said. “It represents a major paradigm shift in the capabilities of antihydrogen research. Experiments that used to take months can now be performed in a single day.”

This breakthrough not only enhances the capabilities of antihydrogen research but also opens new avenues for understanding the universe’s fundamental properties. As physicists continue to unravel the mysteries of antimatter, the implications of this research could have far-reaching consequences for our understanding of the cosmos.

More information on this study can be found in the article by R. Akbari et al., titled “Be⁺ assisted, simultaneous confinement of more than 15,000 antihydrogen atoms,” published in Nature Communications (2025).