Thursday 25 September 2025
A new study published in Physical Review C sheds light on a long-standing problem in astrophysics: the lithium problem. For decades, scientists have struggled to reconcile the observed abundance of lithium in the universe with theoretical predictions.
The lithium problem arises from the mismatch between the amount of lithium predicted by Big Bang nucleosynthesis (BBN) and the actual amount detected in metal-poor stars. BBN is a process that occurred in the first few minutes after the Big Bang, during which light elements were formed from protons, neutrons, and electrons.
The discrepancy has been attributed to various factors, including uncertainties in nuclear reaction rates, changes in the cosmic radiation field, and even the presence of exotic particles not accounted for in the Standard Model of particle physics. However, none of these explanations have been able to fully resolve the issue.
Researchers at Tohoku University have now proposed a new solution: the effect of magnetic fields on nuclear reactions. Their study shows that fluctuations in magnetic fields could enhance the tunneling rate of low-energy nuclear reactions across the Coulomb barrier, thereby increasing the production of lithium-7 (7Li).
The team used ab initio calculations to investigate the impact of magnetic fields on the proton and neutron density distributions of light nuclei, including 2H, 3H, 3He, and 6Li. They found that the asymptotic exponential damping of probability densities at long distances is modified by the presence of a magnetic field.
The researchers showed that the linear component of the exponent with respect to the magnetic field dominates the leading contribution, while second derivatives and confining forces play a subleading role. This means that even small fluctuations in magnetic fields could have a significant effect on nuclear reactions.
The implications of this study are far-reaching. If primordial magnetic fields were strong enough during BBN, they could have increased the production of 7Li, resolving the lithium problem. Alternatively, unwanted magnetic fields generated in experimental setups could be responsible for the discrepancy between theoretical predictions and observed abundances.
While this new explanation is intriguing, it’s not without its challenges. The strength and structure of primordial magnetic fields are still uncertain, and more research is needed to determine whether they could have played a significant role in shaping the universe as we know it today.
The study highlights the importance of considering the interplay between nuclear reactions and electromagnetic forces in understanding the early universe.
Cite this article: “Magnetic Fields May Hold Key to Resolving Lithium Problem”, The Science Archive, 2025.
Astrophysics, Lithium Problem, Big Bang Nucleosynthesis, Nuclear Reactions, Magnetic Fields, Standard Model, Particle Physics, Ab Initio Calculations, Probability Densities, Primordial Magnetic Fields
Reference: Nodoka Yamanaka, “Light nuclei under magnetic field and the lithium problem” (2025).
