Swansea University physicists have contributed to a significant advancement in antihydrogen research at CERN. The breakthrough, part of the international Antihydrogen Laser Physics Apparatus (ALPHA) collaboration, has been published in Nature Communications. The research addresses fundamental questions about the imbalance between matter and antimatter in the universe.
Antihydrogen, which consists of an antiproton and a positron, is the antimatter counterpart to hydrogen. Studying its properties allows scientists to investigate whether antimatter behaves according to the same physical laws as matter.
Traditional methods for producing and trapping antihydrogen were time-consuming, requiring 24 hours to trap approximately 2,000 atoms. The Swansea-led team introduced a new approach using laser-cooled beryllium ions, enabling them to cool positrons below 10 Kelvin—colder than previous limits of about 15 Kelvin. This improvement led to trapping 15,000 antihydrogen atoms in less than seven hours.
This development increases the efficiency of experiments at ALPHA and enables more precise studies on topics such as how antimatter interacts with gravity and whether it follows the same symmetries as matter.
Professor Niels Madsen from Swansea University's School of Biosciences, Geography and Physics, who is also Deputy Spokesperson for ALPHA and lead author of the study, said: “It’s more than a decade since I first realised 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.”
Maria Gonçalves, a PhD student involved in the project, stated: “This result was the culmination of many years of hard work. The first successful attempt instantly improved the previous method by a factor of two, giving us 36 antihydrogen atoms—my new favourite 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.”
Dr Kurt Thompson, another key researcher on the project, commented: “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.”
The full study is available for further reading.