A universe where the fundamental laws that govern everything from atoms to galaxies might not be as immutable as once believed stands at the forefront of scientific inquiry. This contemplation of the constants of nature—critical numbers that dictate the forces, masses, and energies across the universe—evolving as the universe expands, ventures beyond mere speculation. It challenges the foundational principles of physics, inviting us to explore a cosmos where the dynamic interplay of forces and matter redefines our notions of permanence and change.

In a groundbreaking study published in Physics Letters B, Professor Taekoon Lee from Kunsan National University proposes a model suggesting that these fundamental constants, specifically the coupling constants critical to field theories, evolve over time. This research posits a thought-provoking mechanism indicating that the ultraviolet cutoff—a parameter limiting the maximum energy scale in field theories—varies with the expansion of the universe, leading to a time-evolution of these constants.

Professor Lee’s model is grounded on the premise that the cutoff is influenced by the universe’s scale factor, an idea diverging from traditional views of static physical laws. It seamlessly connects the varying renormalized coupling constants, crucial for interactions within the standard model of particle physics, to the Hubble parameter, a measure of the universe’s expansion rate. This notion paints a picture of a universe where the very forces and masses that structure the cosmos subtly transform over cosmic time scales.

Reflecting on the essence of his research, Professor Lee clarified, “A general model is proposed for time-varying coupling constants in field theory assuming the ultraviolet cutoff is a varying entity in the expanding universe.” He elaborated on his hypothesis, stating, “It is assumed that the cutoff depends on the scale factor of the universe and all bare couplings remain constant.”

This study deeply delves into the implications of this model on the standard model constants. One of the most captivating findings is the predicted evolution of the nucleon mass, which is closely linked to the strong force’s coupling constant, hinting at its mirroring of the universe’s expansion. This introduces a concept of a universe where not only the vast cosmic structures but also the fundamental building blocks of matter are subjected to the relentless march of time. In discussing the broader ramifications of his findings, Professor Lee highlighted the sweeping impact of his model across the spectrum of fundamental physics, thereby emphasizing, “The evolution of the standard model constants is discussed.”

The implications of this research are profound, shedding light on the theoretical foundations of varying constants and providing a basis for reconciling these changes with empirical evidence. Observations ranging from the potential variation of the fine structure constant in quasar absorption spectra to precision measurements using optical clocks reinforce the model’s physical relevance. Moreover, the study extends its reach to the ratios of fundamental particle masses and even the gravitational constant, portraying a comprehensive view of a universe in flux.

Supported by the National Research Foundation of Korea, Professor Lee’s work represents a significant step towards unraveling the universe’s most profound aspects. It challenges the age-old notion of immutable physical laws, urging a reconsideration of a universe in constant flux. As this model undergoes further refinement and empirical testing, it holds the promise of revolutionizing our cosmic understanding, offering insights into the universe’s inception and its eventual fate. The quest to demystify the cosmos persists, with Professor Lee’s model illuminating the path towards a deeper comprehension of the universe’s ever-evolving nature.


Taekoon Lee, “A model for time-evolution of coupling constants,” Physics Letters B, 2024.

DOI: https://doi.org/10.1016/j.physletb.2023.138424.