Physicists from Swansea University have made a significant advancement in antihydrogen research at CERN, increasing the antihydrogen trapping rate by a factor of ten. This breakthrough, achieved through the international Antihydrogen Laser Physics Apparatus (ALPHA) collaboration, was published on November 18, 2025, in the esteemed journal Nature Communications. The development could potentially answer a foundational question in physics: Why is there a vast imbalance between matter and antimatter in the universe?
The research builds on the Big Bang theory, which posits that equal amounts of matter and antimatter were produced at the universe’s inception. Yet, the observable universe is dominated by matter. Antihydrogen, the “mirror version” of hydrogen composed of an antiproton and a positron, provides a unique opportunity for scientists to study the behavior of antimatter and determine whether it adheres to the same physical laws as matter.
Producing and trapping antihydrogen has historically been a complex process. Previous techniques required up to 24 hours to trap merely 2,000 atoms, severely limiting experimental capabilities at ALPHA. The Swansea-led team has transformed this approach. By utilizing laser-cooled beryllium ions, they successfully cooled positrons to temperatures below 10 Kelvin, significantly colder than the previous limit of approximately 15 Kelvin.
This innovative cooling process has led to the remarkable achievement of trapping over 15,000 antihydrogen atoms in less than seven hours. This accomplishment paves the way for a new era in antihydrogen research, allowing for a broader range of experiments and more precise tests of fundamental physics. Researchers now have the opportunity to investigate how antimatter responds to gravity and whether it follows the same symmetries as matter.
Professor Niels Madsen, from the School of Biosciences, Geography and Physics and lead author of the study, 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.
The project also involved significant contributions from students. Maria Gonçalves, a leading Ph.D. student on the project, reflected on the hard work that led to this result. “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, praised the collective effort that made this milestone possible. “This fantastic achievement was accomplished by the dedication and collaborative efforts of many Swansea graduate students, summer students, and researchers over the past decade. 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,” he explained.
This breakthrough not only enhances the understanding of antihydrogen but also opens new avenues for future research in fundamental physics, potentially reshaping our comprehension of the universe. As scientists continue to explore these new findings, the implications of this work could have far-reaching effects in the field of particle physics and beyond. For more information, the study is available in Nature Communications under the title, “Be+ assisted, simultaneous confinement of more than 15,000 antihydrogen atoms.”
