A groundbreaking theoretical method for producing axions inside fusion reactors has been proposed by a University of Cincinnati physicist and an international team of collaborators. This scientific advancement addresses a challenge that even the fictional physicists Sheldon Cooper and Leonard Hofstadter from CBS’s “The Big Bang Theory” could not solve.
UC physics professor Jure Zupan, along with co-authors from the Fermi National Laboratory, MIT, and Technion-Israel Institute of Technology, have detailed their findings in a study published in the Journal of High Energy Physics. Their work suggests a potential solution to a problem that has intrigued both real-world scientists and television audiences alike.
Why Axions Matter to Dark Matter Research
Axions are theoretical subatomic particles that have the potential to unlock the mysteries of dark matter. Dark matter is a crucial component in understanding the universe’s formation and evolution since the Big Bang nearly 14 billion years ago. Although it has never been directly observed, physicists estimate that dark matter constitutes the majority of the universe’s mass, with ordinary matter—such as stars, planets, and humans—making up only a small fraction.
Dark matter is so named because it neither absorbs nor reflects light, making it invisible to current detection methods. Its presence is inferred through gravitational effects, such as the unusual motions of galaxies and stars. One prevailing theory is that dark matter is composed of extremely light particles known as axions.
Fusion Reactors as a Source of New Particles
The study by Zupan and his colleagues explores a fusion reactor design utilizing deuterium and tritium fuel within a lithium-lined vessel. This reactor type is currently under development through an international collaboration in southern France. Such reactors are expected to generate vast numbers of neutrons alongside energy, and these neutrons could potentially lead to the creation of particles associated with the dark sector.
“Neutrons interact with material in the walls. The resulting nuclear reactions can then create new particles,” Zupan explained. Another potential production method involves neutrons colliding with other particles and slowing down, releasing energy through a process known as bremsstrahlung, or “braking radiation.”
Through these mechanisms, the reactor could theoretically produce axions or axion-like particles, a feat that eluded the fictional physicists on television.
The Big Bang Theory Easter Egg Explained
“The Big Bang Theory,” which aired from 2007 to 2019, won seven Emmys and remains a popular show on streaming platforms, according to Nielsen. “The general idea from our paper was discussed in ‘The Big Bang Theory’ years ago, but Sheldon and Leonard couldn’t make it work,” Zupan noted.
In one episode, a whiteboard displays an equation and diagram that Zupan says represent how axions are produced in the sun. In a later episode, another equation appears on a different board, with a sad face drawn underneath in a different marker color, symbolizing failure. Zupan explained that the equation compares the chances of detecting axions from a fusion reactor with those from the sun, with the latter being more likely due to the sun’s immense power output.
“The sun is a huge object producing a lot of power. The chance of having new particles produced from the sun that would stream to Earth is larger than having them produced in fusion reactors using the same processes as in the Sun. However, one can still produce them in reactors using a different set of processes,” he said.
The show never explicitly mentions axions or explains the whiteboards, leaving these as inside jokes for scientists. This is fitting for a series known for integrating complex scientific concepts into its plots, alongside appearances by Nobel Prize winners and “Star Trek” alumni.
“That’s why it’s fantastic to watch as a scientist,” Zupan said. “There are many layers to the jokes.”
Implications and Future Research
The proposed method for producing axions in fusion reactors represents a significant step forward in dark matter research. If successful, it could provide new insights into the nature of dark matter and its role in the universe. However, much work remains to be done to translate this theoretical framework into practical experiments.
Future research will likely focus on refining the proposed methods and exploring the feasibility of detecting axions produced in fusion reactors. As fusion technology continues to advance, the possibility of using these reactors as a tool for fundamental physics research becomes increasingly promising.
For now, the scientific community remains cautiously optimistic, with many eagerly awaiting further developments in this exciting field of study.
