Researchers M. Gomes, A. C. Lehum, and A. J. da Silva from the Federal University of Ceará in Brazil have revisited the concept of how electric charge behaves in a specific theoretical framework that combines quantum electrodynamics (QED) with a particular model of gravity. Their work, published in the journal Physical Review D, focuses on understanding how electric charge changes, or “runs,” in this combined theoretical setting.
In their study, the researchers compared two different methods for calculating how electric charge changes. The first method is the conventional approach, which uses a mathematical tool called minimal subtraction to remove infinities that appear in calculations. The second method is a more physically intuitive approach that looks at how certain quantities depend on a large energy scale, after accounting for effects from low-energy scales.
The team specifically looked at the photon vacuum polarization, a phenomenon where a photon briefly fluctuates into a particle-antiparticle pair and back into a photon, at one loop, which is a specific level of approximation in quantum field theory. They found that in this context, there is a clear distinction between effects coming from very high energies (ultraviolet, or UV) and those coming from very low energies (infrared, or IR). The UV effects are independent of the gauge chosen and determine the rate at which the electric charge changes, while the IR effects are more complex and can depend on the gauge.
Interestingly, when they included the effects of quadratic gravity—a specific model of gravity—they found that the photon self-energy, which is a measure of how the photon interacts with itself, was finite and did not contribute to the UV running of the electric charge. This means that quadratic gravity does not alter the way the electric charge changes at this level of approximation. The researchers concluded that their analysis provides a clear method for extracting a gauge and process-independent running of electric charge in the presence of gravitational interactions.
This research is significant for the energy industry as it deepens our understanding of fundamental physical theories that underpin many energy technologies. While the study is theoretical, it contributes to the broader scientific knowledge base that could eventually lead to advancements in energy generation, transmission, and storage technologies. For instance, a better understanding of how electric charge behaves in different theoretical frameworks could inform the development of more efficient and sustainable energy solutions.
This article is based on research available at arXiv.