Swansea Physicists Achieve Breakthrough in Antihydrogen Trapping

Physicists from Swansea University have achieved a significant breakthrough in antihydrogen research at CERN, enhancing the trapping rate of antihydrogen by a factor of ten. This advancement, part of the international Antihydrogen Laser Physics Apparatus (ALPHA) collaboration, has been detailed in a recent publication in Nature Communications and could provide insights into the longstanding mystery of why the universe is predominantly composed of matter.

According to the Big Bang theory, equal amounts of matter and antimatter were produced at the universe’s inception. Yet, our observable universe is almost entirely made of matter. The newly developed technique allows researchers to trap antihydrogen, the “mirror version” of hydrogen consisting of an antiproton and a positron, making it possible to study its properties and behavior.

Historically, producing and trapping antihydrogen has been a complex process, with previous methods requiring up to 24 hours to trap merely 2,000 atoms. The Swansea-led team has revolutionized this process. By employing laser-cooled beryllium ions, they successfully cooled positrons to below 10 Kelvin (approximately -263°C), significantly reducing the temperature from the previous threshold of around 15 Kelvin. This improvement has resulted in the record trapping of 15,000 antihydrogen atoms in less than seven hours.

Expanding Research Horizons

This breakthrough signals a new era for the ALPHA collaboration, broadening the scope of experiments and enabling more precise investigations into fundamental physics. Researchers can now conduct tests on how antimatter interacts with gravity and whether it adheres to the same symmetries as matter.

Professor Niels Madsen, lead author of the study and Deputy Spokesperson for ALPHA, expressed his excitement: “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.”

The project has also inspired the next generation of researchers. Maria Gonçalves, a leading Ph.D. student involved in the study, remarked, “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 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.”

Dr. Kurt Thompson, a prominent researcher on the team, highlighted the collaborative effort that made this achievement 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.”

This significant advancement not only enhances our understanding of antihydrogen but also opens up new pathways in the field of physics, allowing scientists to explore fundamental questions about the universe and its composition.

Further details on this research 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 on November 18, 2025.